Court Opinion

ID: 9297603
Source: CourtListenerOpinion
Date Created: 2022-11-30 21:01:20.045188+00
Date Added: 2024-06-11T17:13:28.886955
License: Public Domain

USCA11 Case: 18-13967     Date Filed: 11/30/2022   Page: 1 of 39

                                           [DO NOT PUBLISH]
                            In the
         United States Court of Appeals
                 For the Eleventh Circuit

                   ____________________

                         No. 18-13967
                   ____________________

UNITED STATES OF AMERICA,
                                              Plaintiff-Appellee,
versus
ANDRES MENCIA,

                                           Defendant-Appellant.

                   ____________________

          Appeal from the United States District Court
              for the Southern District of Florida
            D.C. Docket No. 0:17-cr-60301-WPD-1
                   ____________________
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2                          Opinion of the Court                      18-13967

    ON REMAND FROM THE SUPREME COURT OF THE
                     UNITED STATES
Before GRANT and BRASHER, Circuit Judges.1
PER CURIAM:
        This appeal returns to us on remand from the Supreme
Court of the United States. After we affirmed Andres Mencia’s con-
viction for conspiracy to violate the Controlled Substances Act, 21
U.S.C. § 841(a), by dispensing controlled substances without a le-
gitimate medical purpose, in violation of 21 U.S.C. § 846, United
States v. Mencia, 861 F. App’x 736, 739 (11th Cir. 2021), the Su-
preme Court issued its decision in Ruan v. United States, 597 U.S.
----, 142 S. Ct. 2370, 2374 (2022). The Court granted Mencia’s peti-
tion for certiorari, vacated our judgment, and remanded his appeal
for further consideration in light of Ruan. See United States v. Men-
cia, 142 S. Ct. 2897 (2022).
       Mencia, a formerly licensed physician, owned and operated
a geriatric specialty clinic where many patients, often younger and
addicted to drugs, would pay cash in exchange for narcotic pre-
scriptions. Mencia argues that (1) there was insufficient evidence to
support his conviction, (2) the district court abused its discretion in
making certain evidentiary rulings, (3) the Controlled Substances
Act is unconstitutionally vague as applied to physicians, and (4) the
instructions provided to the jury constitute reversible error under

1 Judge Martin retired from active service to this Court and did not participate
in this decision, which is rendered by quorum. 28 U.S.C. § 46(d).
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18-13967                    Opinion of the Court                             3

the Supreme Court’s holding in Ruan. 2 We disagree. The govern-
ment presented overwhelming evidence of Mencia’s guilt, the dis-
trict court did not abuse its discretion, this Court has already held
that the Act is not unconstitutional as applied to physicians, and the
jury instructions do not constitute reversible error, even in light of
Ruan. Accordingly, we affirm.
                         I.      BACKGROUND

                       A.      Factual Background

       Andres Mencia, a formerly licensed physician, owned and
practiced at Adult & Geriatric Institute of Florida, Inc., in Oakland
Park, Florida. Although AGI was not a pain clinic and Mencia was
not a pain specialist, a significant amount of his business came from
prescribing opioids and other controlled substances to certain pa-
tients who paid in cash. Mencia called those individuals “Code-G”
patients, with the “G” standing for “gypsy,” because they did not
have insurance. Even though other patients also paid in cash, Code-
G patients never paid at the checkout counter. Instead, Mencia as-
signed certain medical assistants to collect their payments. Mencia
often prescribed these Code-G patients a combination of Percocet,
Xanax, and Soma, which one of the government’s experts, Dr. San-
ford Silverman, described as the “holy trinity”––a trio consisting of

2 Mencia’s first three arguments were addressed in our now vacated opinion.
For the sake of completeness, we address these three arguments again in ad-
dition to the fourth argument, which was not raised in Mencia’s initial appeal.
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4                     Opinion of the Court                18-13967

an opioid, benzodiazepine, and a muscle relaxant that drug-seeking
patients often request.
       Between January 1, 2014, and May 31, 2018, Mencia wrote
45,000 controlled substance prescriptions. Around one-third of
those prescriptions were for patients who paid in cash. Those pa-
tients who were covered by Medicare or commercial insurance of-
ten received more prescriptions than just the “holy trinity”; they
would also receive Dilaudid, Oxycontin, or amphetamines. And
Mencia consistently prescribed the highest possible dose strength
of controlled substances, including oxycodone and Xanax.
       One patient, JH, returned monthly for controlled substance
prescriptions after Mencia initially diagnosed him with back pain
without an examination. JH’s girlfriend and grandmother each
called the front desk at AGI to inform them that JH was an opioid
addict, but Mencia continued to prescribe him oxycodone and
Soma. In fact, Mencia continually increased JH’s doses and even
gave him refills when JH claimed that his prescriptions had been
stolen. JH eventually fatally overdosed on oxycodone and Xanax.
       Oscar Luis Ventura-Rodriguez, one of Mencia’s medical as-
sistants, testified that when he first started at AGI, Mencia would
spend some time with Code-G patients and then Ventura-Rodri-
guez would write them prescriptions, which Mencia would sign.
The majority of those prescriptions were for Percocet. But Mencia
never physically examined those patients, and the consultations
usually only lasted around ten minutes.
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18-13967               Opinion of the Court                        5

       Over time, the number of Code-G patients increased, and
Mencia stopped entering the room at all when returning patients
came in. Instead, medical assistants would look up what prescrip-
tions the patients had previously been given, fill the prescriptions
out the same way as before, then take them to Mencia to sign. The
patients would receive those controlled substance prescriptions
without an examination and without any physician reviewing
whether the medications were medically necessary.
       The price that AGI charged Code-G patients also increased
over time. And Mencia instructed his assistants to get those patients
out of the waiting room as soon as they arrived. Although Mencia
instructed his medical assistants to ask Code-G patients for MRIs,
not having one did not affect their ability to get a prescription for
controlled substances.
       Ventura-Rodriguez testified that, as the number of Code-G
patients increased, Mencia began instructing him and other assis-
tants on which medications and how many pills to prescribe before
patients ever arrived. At that point, Ventura-Rodriguez began to
suspect that many Code-G patients were not truly in pain. He
shared that suspicion with Mencia, but Mencia continued to sign
the controlled substance prescriptions. Eventually, Mencia did not
even enter the room to see new Code-G patients.
       Mencia also instructed the assistants on how to write the
charts to justify the prescriptions that he was signing for the new
Code-G patients. He instructed them to note the level of a patient’s
pain, not based on a consultation with the patient, but based on the
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6                      Opinion of the Court                 18-13967

level necessary to prescribe the drugs that Mencia had instructed
them to give. Toward the end of this operation, Mencia would pre-
sign blank prescriptions so that the medical assistants did not even
have to bring them to him to sign. The government entered into
evidence several text messages between Mencia and Ventura-Ro-
driguez that confirmed his testimony that Mencia had provided
him with pre-signed prescriptions and had allowed him to write
prescriptions before the date that another prescription was legally
permitted.
       To help with his increasing patient load, Mencia contracted
with a pain clinic in 2014 to hire Dr. Gabriel Marrero, a pain man-
agement specialist, to work one day per week at AGI. Marrero
quickly became concerned that many of AGI’s patients were not
interested in interventional pain, which was his specialty, and only
cared about acquiring controlled substances. He also noticed that
urine tests, MRIs, and x-rays were missing from patient files. He
brought his concerns to Mencia’s attention, and Mencia agreed that
these issues needed to be addressed. But Marrero continued to see
the same issues in patient files, which led him to discharge those
patients. Unbeknownst to Marrero, Mencia would often take those
patients back.
      Mencia took back one such patient after Marrero had dis-
charged him for failing a urine test. That patient testified to having
a drug addiction and to selling his prescriptions to buy more her-
oin. When he asked Mencia for larger quantities of the pills because
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18-13967               Opinion of the Court                       7

his tolerance had increased, Mencia complied for all but one medi-
cation, saying that he had to “stay under the radar.”
       The beginning of the end for Mencia came when Dr. Abby
Goldstein, a pharmacist at Publix Pharmacy, became concerned
about the large number of oxycodone prescriptions that Code-G
patients were bringing to the pharmacy. Dr. Goldstein informed
the DEA about her concerns, telling them that Mencia “might be
overprescribing certain medications,” including opioids. Dr. Gold-
stein testified that Mencia’s prescriptions stood out because
“[n]inety-five percent of them were for a large quantity immediate-
release narcotics,” particularly Percocet and oxycodone. Even
though “a lot” of physicians were listed on the prescriptions from
Mencia’s office, she only received prescriptions from Mencia. She
was also concerned because, when she called AGI for the diagnosis
codes for these prescriptions, she was told the same diagnosis for
most patients. And when she looked Mencia up on the Board of
Health license verification website, she discovered that he was not
specially certified in pain management despite the large number of
pain medications that he was prescribing. Due to her growing con-
cerns, Dr. Goldstein refused to fill approximately eighty percent of
Mencia’s prescriptions for narcotics.
       Also, as a result of Dr. Goldstein’s concerns, the government
sent confidential informants into AGI to pretend that they were in
pain and attempt to obtain controlled substance prescriptions. In
the videos captured by those informants, medical assistants can be
seen prescribing controlled substances on pre-signed prescription
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8                      Opinion of the Court                18-13967

pads without Mencia ever entering the room or seeing the patients.
The videos also show the patients paying in cash and sometimes
“tipping” the assistants. The assistants would then pocket that cash.
Ventura-Rodriguez testified, however, that he would later give
that cash to someone else.
       Mencia was originally indicted along with three members of
his office staff, Ventura-Rodriguez, Nadira Sampath-Grant, and
John Mensah, for conspiracy to commit health care fraud and wire
fraud and conspiracy to dispense controlled substances. Ventura-
Rodriguez, Sampath-Grant, and Mensah each subsequently en-
tered into plea agreements with the government and agreed to tes-
tify against Mencia. Mencia was then charged in a fifth superseding
indictment with (1) conspiracy to commit health care fraud and
wire fraud in violation of 18 U.S.C. § 1349; (2) conspiracy to dis-
pense oxycodone in violation of 21 U.S.C. § 846; (3) dispensing ox-
ycodone in violation of 21 U.S.C. § 841(a)(1); (4) seven counts of
money laundering in violation of 18 U.S.C. § 1957(a); and (5) struc-
turing to avoid reporting requirements in violation of 31 U.S.C. §
5324(a)(3) and (d)(2).
       Mencia requested expert disclosures the day after he was in-
dicted. One month later, and thirteen days before trial started, the
government disclosed six experts, including Dr. Silverman. The
government disclosed two additional experts the next day, includ-
ing Dr. Jodi Sullivan. The defense filed a motion in limine to ex-
clude the proposed expert testimony on the grounds that the
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18-13967               Opinion of the Court                        9

government’s disclosures were untimely. The district court denied
the motion.
        Dr. Silverman is a licensed physician and pain management
specialist. He has published around nineteen articles in peer re-
viewed journals and a textbook on controlled substance manage-
ment in chronic pain patients. The government presented Dr. Sil-
verman as an expert on pain management and addiction “with the
ability to opine on . . . the accepted scope of professional practice
and whether medications are issued for a legitimate medical pur-
pose.” Mencia objected on the grounds that (1) the term “scope of
professional practice” does not appear in the statute under which
Mencia was charged and (2) there had not been any testimony as
to the methodology that Dr. Silverman used to reach his opinions.
The court overruled his objection. Before testifying, Dr. Silverman
reviewed Mencia’s prescribing history through the Florida Pre-
scription Drug Monitoring Plan, several videos that were taken at
AGI by confidential government informants, and a selected num-
ber of patient notes.
       Based on his review of the evidence, Dr. Silverman opined
that the controlled substances that Mencia prescribed in the period
between 2014 and 2017 “did not have a medical legitimate need.”
When asked whether there are Florida statutes that “act as guid-
ance as to what is and is not acceptable practice,” Dr. Silverman
replied that “[t]hey’re law. They’re not guidance.” And he deter-
mined that Mencia had violated those laws by failing to record
proper medical examinations prior to prescribing controlled
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10                      Opinion of the Court                   18-13967

substances, develop a written treatment plan for assessing patients’
apparent drug-seeking behavior, or document an assessment of pa-
tients’ risk related to that behavior or monitor the behavior on an
ongoing basis. He also said that Mencia’s failure to refer patients
whom he was treating for anxiety to psychiatrists violated the law.
He was also concerned by the combination of medications that
Mencia was prescribing due to the risk of fatal overdose. And he
stated that it is both outside the scope of professional practice and
outside Florida law for a physician to re-prescribe opioids after only
a very brief check-in with the patient.
        Dr. Silverman also testified that it is illegal under Florida law
for medical assistants to fill out prescriptions or make diagnoses or
treatment plans. Their job, he stated, is to give the physician the
facts so that the physician can conduct an informed exam and come
up with a plan. And he considered it to be outside the scope of pro-
fessional practice for a medical assistant to see a patient, brief the
doctor, and then for the doctor to sign a prescription for a con-
trolled substance without seeing the patient himself.
        The defense asked Dr. Silverman whether there is criminal
liability for violating Florida statutes regarding the standard of
medical practice. First, the defense tried to ask Dr. Silverman to
locate where the statutes provide for jail time. The government
objected to that question as irrelevant, and the court sustained the
objection. The defense then asked whether a certain statute is en-
forced by the Board of Medicine. Dr. Silverman responded that “it
is my understanding that if you violate [Florida Statute §] 456.44,
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18-13967               Opinion of the Court                      11

that––it was my understanding there were criminal penalties. I
don’t know specifically what they were. But since they are law, I
believe they (sic) were some penalties.” He then explained that “the
enforcement of this I believe is through the DOH, Department of
Health,” and “I don’t know if the patient goes before the Board of
Medicine when you violate this. I believe this is a law. So, I think
this is taken out of the administrative realm of the Board of Medi-
cine. That’s my understanding.” The defense objected and moved
to strike those comments as “an incorrect statement of law.”
        The court asked the government to stipulate that there are
no criminal penalties in Section 456.44. The government stated
that it was not aware of anything in Section 456.44 stating that it
carries criminal penalties. The defense then asked again whether a
violation of Section 456.44 is brought before the Board of Medicine
and emphasized that Dr. Silverman was brought before the Board
of Medicine for a violation of that same statute for wrong-site in-
jections.
       In its pretrial disclosures, the government stated that Dr.
Sullivan, a licensed pharmacist, would testify regarding how Men-
cia’s unusual patterns of prescribing controlled substances were
consistent with a “pill mill” based on her review of Mencia’s pre-
scription data from the Florida Department of Health and Prescrip-
tion Drug Event. Dr. Sullivan reviewed the Medicare Part D and
Part B records for Mencia, a date-of-death analysis, and the Florida
Prescription Drug Monitoring Program data for Mencia and 54 of
his patients before testifying. The defense objected to Dr. Sullivan
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12                     Opinion of the Court                18-13967

being tendered as an expert again at trial on the grounds that the
government had not disclosed what methodology she used to
reach her conclusions. The defense also requested a Daubert hear-
ing. The court overruled the objection and stated that “she’s a qual-
ified expert.”
       Dr. Carol Warfield testified for the defense. She teaches pain
management at Harvard Medical School and elsewhere and has
written textbooks on the subject. She was originally hired by the
government but was dropped as a witness after opining that Men-
cia was acting as a medical doctor in the usual course of medical
practice based on the medical records and videos that they asked
her to review. She also informed the government that she “had
concerns” about the fact that he was signing blank prescriptions.
The defense asked Dr. Warfield whether pre-signing blank pre-
scriptions carries criminal penalties under Florida law, to which the
government objected. The court sustained the objection.
        During cross-examination, the government asked Dr.
Warfield about her concerns over the pre-signing of prescriptions.
The prosecutor asked: “I believe what you told me was that under
no circumstance would it be within the scope of professional prac-
tice to give a medical assistant a presigned prescription for them to
fill out at their discretion for controlled two (sic) substances. Do
you agree with that?” The defense objected and the court over-
ruled, stating that “what the lawyers say isn’t evidence. The an-
swers are evidence. If he wants to pursue this and waive his attor-
ney-client –– waive his work product, he can do that.” Dr. Warfield
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18-13967               Opinion of the Court                        13

answered that she “thought those medical assistants were practic-
ing medicine without a license, and they in no way should have
been given blank prescriptions to prescribe opiates to these pa-
tients.”
        The government referenced that testimony in closing. It
stated that the core of the case was “about a doctor acting outside
the scope of professional practice and not for a legitimate medical
purpose when he provides medical assistants with presigned pre-
scriptions.” The government then stated, “what you heard from
both experts that on this matter, there is no dispute. It is outside
the scope of professional practice and not for a legitimate purpose
to hand out presigned prescriptions for the medical assistants to fill
in if the doctor has never seen the patient.” The government then
reiterated, “[t]here’s no dispute about that.”
       Prior to jury deliberations, the district court gave several
jury instructions, two of which Mencia now challenges on appeal.
First, Mencia challenges the so called “good faith” instruction—
which Mencia requested. That instruction required the jury to
“find that the government proved beyond a reasonable doubt that
[Mencia’s] treatment and prescription of controlled substances
were not undertaken with a reasonable good faith belief that he
was acting with a legitimate medical purpose and according to the
generally recognized and accepted standard of care.” Second, Men-
cia challenges the jury instruction describing the requirements to
convict him of conspiracy to dispense oxycodone unlawfully. The
instruction stated that Mencia could only be found guilty if the
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14                      Opinion of the Court                  18-13967

Government proved beyond a reasonable doubt that (1) he and an-
other person “in some way agreed to try to accomplish a shared
and unlawful plan to distribute or dispense a con-trolled substance,
outside the scope of professional practice and not for a legitimate
medical purpose”; (2) Mencia “knew the un-lawful purpose of the
plan and willfully joined in it”; and (3) the purpose of the plan, “was
to distribute or dispense a controlled substance, outside the scope
of professional practice and not for a legitimate medical purpose.”
      The jury returned a guilty verdict only as to Count Two:
conspiracy to dispense oxycodone unlawfully. Mencia timely ap-
pealed.
                   B.     Procedural Background

        In his initial appeal, Mencia argued that the government
failed to provide sufficient evidence of his guilt, the district court
erred by admitting certain expert testimony, and 21 U.S.C. § 841 is
not unconstitutionally vague as applied to physicians. We rejected
these arguments and affirmed Mencia’s conviction on the same
grounds explained below. Notably, Mencia did not challenge the
sufficiency of the jury instructions at the district court or on appeal.
        Following our affirmance of his conviction, Mencia filed a
pro se petition for writ of certiorari before the United States Su-
preme Court. For the first time, Mencia argued, among other
things, that the jury instructions at his trial were insufficient. After
the filing of his petition, the Supreme Court issued its decision in
Ruan. The Court then granted Mencia’s petition for certiorari,
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18-13967               Opinion of the Court                        15

vacated our judgment, and remanded his appeal for further consid-
eration in light of Ruan. Mencia, 142 S. Ct. 2897 (2022), vacated,
Ruan, 142 S. Ct. 2370. We asked the parties to file supplemental
briefs addressing the impact of Ruan on this appeal and they timely
did so.
                 II.    STANDARD OF REVIEW

        This Court reviews de novo whether sufficient evidence ex-
ists to support a guilty jury verdict, “reviewing the evidence in the
light most favorable to the government and resolving all reasona-
ble inferences and credibility evaluations in favor of the verdict.”
United States v. Moran, 778 F.3d 942, 958 (11th Cir. 2015).
        We review the district court’s decision whether to admit ex-
pert testimony, and the district court’s assessment of the reliability
of that testimony, for abuse of discretion and will only reverse the
district court if its ruling was manifestly erroneous. United States
v. Frazier, 387 F.3d 1244, 1258 (11th Cir. 2004) (en banc) (quoting
Gen. Elec. Co. v. Joiner, 522 U.S. 136, 142 (1997)). We likewise re-
view the district court’s decision whether to strike testimony for
abuse of discretion. Mich. Millers Mut. Ins. Corp. v. Benfield, 140
F.3d 915, 920–21 (11th Cir. 1998). Accordingly, “we must affirm un-
less we find that the district court has made a clear error of judg-
ment, or has applied the wrong legal standard.” Frazier, 387 F.3d at
1259.
      We review a challenge to a statute’s constitutionality de
novo. United States v. Knight, 490 F.3d 1268, 1270 (11th Cir. 2007).
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16                      Opinion of the Court                   18-13967

       Finally, “[w]e review the legal correctness of jury instruc-
tions de novo.” United States v. Cooper, 926 F.3d 718, 736 (11th
Cir. 2019). Jury instructions objected to before the district court are
subject to harmless error review, meaning this Court will not re-
verse if it finds beyond a reasonable doubt that an erroneous in-
struction did not affect the verdict. United States v. House, 684 F.3d
1173, 1196-97 (11th Cir. 2012). However, “jury instructions that are
challenged for the first time on appeal are reviewed for plain error.”
United States v. Felts, 579 F.3d 1341, 1343 (11th Cir. 2009).
                         III.     DISCUSSION

       In his initial appeal, Mencia raised three arguments, each of
which we rejected in Mencia, 861 Fed. Appx 736. Mencia now also
challenges the sufficiency of the jury instructions in light of Ruan.
We address each argument in turn.
                 A.      Sufficiency of the Evidence

        Mencia argues that there was insufficient evidence to sup-
port his conviction for conspiracy to violate Section 841(a). Specif-
ically, on remand, he argues that there was insufficient evidence
elicited at trial to prove beyond a reasonable doubt that he know-
ingly or willingly distributed oxycontin in an unauthorized man-
ner. We disagree.
       The Controlled Substances Act makes it illegal for anyone
to “knowingly or intentionally . . . . distribute . . . a controlled sub-
stance.” 21 U.S.C. § 841(a)(1). But there is an exception for licensed
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18-13967                Opinion of the Court                         17

health care professionals––they may prescribe Schedule II, III, and
IV controlled substances so long as the prescription is for a “legiti-
mate medical purpose[] in the usual course of professional prac-
tice.” United States v. Joseph, 709 F.3d 1082, 1102 (11th Cir. 2013)
(quoting United States v. Ignasiak, 667 F.3d 1217, 1228 (11th Cir.
2012)). To convict a physician of violating Section 841(a)(1), the
government must “prove that he dispensed controlled substances
for other than legitimate medical purposes in the usual course of
professional practice, and that he did so knowingly and intention-
ally.” Joseph, 709 F.3d at 1102 (quoting Ignasiak, 667 F.3d at 1228).
“Because the Act prohibits the distribution of prescription drugs
that is not authorized, a distribution is unlawful if 1) the prescrip-
tion was not for a ‘legitimate medical purpose’ or 2) the prescrip-
tion was not made in the ‘usual course of professional practice.’”
Id. (cleaned up) (quoting United States v. Tobin, 676 F.3d 1264,
1282 (11th Cir. 2012), abrogated on other grounds by United States
v. Davila, 569 U.S. 597, 610 (2013)). In Ruan, the Court held that,
in a 21 U.S.C. § 841(a) prosecution of a licensed physician for dis-
pensing unauthorized controlled substance prescriptions, the gov-
ernment must prove beyond a reasonable doubt that the physician
knew that the prescriptions were unauthorized. 142 S. Ct. at 2374.
        Section 846 makes it illegal to conspire to violate Section
841(a)(1). See 21 U.S.C. § 846. To convict a defendant of violating
Section 846, the government must prove that “(1) there was an
agreement between two or more people to unlawfully distribute .
. . controlled substances in violation of § 841(a)(1); (2) the defendant
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18                     Opinion of the Court                18-13967

knew about the agreement; and (3) the defendant ‘voluntarily
joined’ the agreement.” United States v. Iriele, 977 F.3d 1155, 1169
(11th Cir. 2020) (quoting United States v. Azmat, 805 F.3d 1018,
1035 (11th Cir. 2015)). The government may prove the first ele-
ment, the existence of an agreement, “by proof of an understand-
ing between the participants to engage in illicit conduct[.]” United
States v. Achey, 943 F.3d 909, 916 (11th Cir. 2019). And the govern-
ment may prove that understanding through circumstantial evi-
dence. Id.
        “[R]esolving all reasonable inferences and credibility evalu-
ations in favor of the verdict,” Moran, 778 F.3d at 958, we conclude
that sufficient evidence supports the jury’s verdict. Indeed, the ev-
idence in this case is comparable to the evidence in in similar cases
where we have affirmed guilty verdicts. Mencia set aside a class of
patients known as “Code-G” patients and, even though he is a ger-
iatric specialist, prescribed them the “holy trinity” of controlled
substances for cash. Eventually, as in Joseph, Mencia distributed
these drugs by pre-signing and pre-dating prescriptions and in-
structing his medical assistants to give out those prescriptions. See
Joseph, 709 F.3d at 1102. And he prescribed these controlled sub-
stances “without conducting any physical examination of the pa-
tient,” which “provides strong evidence to support a conviction un-
der the Act.” Id. Moreover, Mencia continued to prescribe the
“holy trinity” to various patients despite obvious signs of drug-
seeking behavior that led Dr. Marrero to reject them. Ventura-Ro-
driguez testified that, as the number of Code-G patients increased,
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18-13967                Opinion of the Court                        19

Mencia stopped entering the examination rooms at all––let alone
physically examining the patients––before the medical assistants
gave the patients prescriptions. And the video evidence gathered
by confidential informants supports that testimony.
       This Court has found sufficient evidence that a physician dis-
tributed a prescription without a legitimate medical purpose and
outside the usual course of professional conduct where, among
other factors: “(1) An inordinately large quantity of controlled sub-
stances was prescribed[,] . . . (2) [l]arge numbers of prescriptions
were issued[,]” (3) “[t]he physician prescribed controlled drugs at
intervals inconsistent with legitimate medical treatment[,]” and (4)
“[t]here was no logical relationship between the drugs prescribed
and treatment of the condition allegedly existing.” United States v.
Rosen, 582 F.2d 1032, 1036 (5th Cir. 1978). Here, Mencia regularly
prescribed the maximum lawful dose of controlled substances and
combined them with high doses of other controlled substances.
And he wrote over 45,000 controlled substance prescriptions in less
than four years. He refilled at least one patient’s prescriptions early
based on claims that the prescriptions had been stolen and author-
ized Ventura-Rodriguez to write prescriptions before the date that
they were allowed. And several witnesses testified that there was
no logical connection between the opioids that Mencia prescribed
and the medical conditions that he was purporting to treat. Each of
these pieces of evidence is “strong evidence to support a conviction
under the Act.” Joseph, 709 F.3d at 1102.
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20                     Opinion of the Court                18-13967

        The government also provided sufficient evidence that an
agreement existed between Mencia and his medical assistants to
unlawfully distribute controlled substances and Mencia knew that
this distribution was not authorized. An “agreement may be in-
ferred when the evidence shows a continuing relationship that re-
sults in the repeated transfer of illegal drugs to the purchaser.”
United States v. Mercer, 165 F.3d 1331, 1335 (11th Cir. 1999). Here,
Mencia’s medical assistants testified at length about the under-
standing between them and Mencia that they could fill in pre-
signed prescriptions for controlled substances without a physician
ever examining the patients. Mencia instructed the assistants to fill
in patient charts, not based on a patient’s actual data, but based on
the “data that would justify the reason why the patient would be
prescribed the drugs.” And the medical assistants did so. Through
this testimony, the government demonstrated that Mencia and his
medical assistants had an agreement that he would instruct them
on what controlled substances to prescribe, for no legitimate med-
ical reason and outside the usual course of professional practice,
and that they would unlawfully write those prescriptions in ex-
change for patients’ cash payments. Accordingly, there was suffi-
cient evidence to support Mencia’s conviction.
                      B.    Expert Witnesses

       Mencia next argues that the district court abused its discre-
tion in allowing certain expert testimony. He challenges the district
court’s resolution of in-trial objections to specific portions of Dr.
Silverman’s and Dr. Warfield’s testimony. And he argues that
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18-13967                Opinion of the Court                         21

neither Dr. Silverman nor Dr. Sullivan should have been allowed
to testify as experts at all.
           1.     In-trial Objections to Expert Testimony
       First, Mencia argues that the district court abused its discre-
tion in allowing Dr. Silverman to testify that, in his opinion, Mencia
acted outside the scope of professional practice in treating certain
patients. We disagree. An expert witness may testify about an opin-
ion that “embraces an ultimate issue,” Fed. R. Evid. 704(a), but may
not “merely tell the jury what result to reach” or “testify to the legal
implications of conduct[.]” Montgomery v. Aetna Cas. & Sur. Co.,
898 F.2d 1537, 1541 (11th Cir. 1990). “In a criminal case, an expert
witness must not state an opinion about whether the defendant did
or did not have a mental state or condition that constitutes an ele-
ment of the crime charged or of a defense.” Fed. R. Evid. 704(b). In
other words, “the expert cannot expressly state a conclusion that
the defendant did or did not have the requisite intent,” United
States v. Alvarez, 837 F.2d 1024, 1031 (11th Cir. 1988), but he can
provide an opinion as to facts that support such a conclusion,
United States v. Augustin, 661 F.3d 1105, 1123 (11th Cir. 2011).
       Dr. Silverman opined that the controlled substances that
Mencia prescribed to certain patients “did not have a medical legit-
imate need.” And he stated that Florida law defines what is and is
not within the scope of professional practice for physicians licensed
in the state. Based on those laws, he opined that Mencia was acting
outside the scope of professional practice when he failed to (1) rec-
ord proper medical examinations prior to prescribing controlled
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22                     Opinion of the Court                 18-13967

substances, (2) develop a written treatment plan for assessing pa-
tients’ apparent drug-seeking behavior, or (3) document an assess-
ment of patients’ risk related to that behavior or monitor the be-
havior on an ongoing basis. He further testified that allowing med-
ical assistants to fill out prescriptions or make diagnoses or treat-
ment plans violates Florida law.
        The district court did not abuse its discretion in admitting
this testimony. To prove that Mencia was guilty of conspiracy to
unlawfully distribute controlled substances, the government had to
prove that he knowingly and intentionally dispensed those sub-
stances for other than legitimate medical purposes in the usual
course of professional practice. See Joseph, 709 F.3d at 1094. But
Dr. Silverman did not testify that Mencia knowingly and intention-
ally acted outside the usual course of professional practice. Instead,
he testified that, in his opinion, because Mencia’s actions violated
Florida law, Mencia was acting outside the usual course of profes-
sional practice. Whether Mencia knew that he was doing so or in-
tended to do so is another question.
        That intent question, whether a physician knowingly and in-
tentionally prescribed a medication for other than a legitimate
medical purpose outside the usual course of professional practice,
is for the jury. See United States v. Guerrero, 650 F.2d 728, 734 (5th
Cir. 1981 Unit A). But what practices fall within the usual course of
professional practice is precisely what an expert witness is needed
to define. Based on that definition and Dr. Silverman’s opinions,
the jury was free to infer whether or not Mencia knew he was
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18-13967               Opinion of the Court                       23

acting or intended to act outside of the usual course of professional
practice or whether he knew he was prescribing or intended to pre-
scribe medications without a legitimate medical purpose. See
United States v. Greenfield, 554 F.2d 179, 184–86 (5th Cir. 1977).
Because Dr. Silverman did not state that Mencia had the requisite
intent to commit the crime alleged, but instead offered his opinion
that Mencia was acting outside the usual course of professional
practice and without a legitimate medical justification, the district
court did not err in allowing his testimony.
        Second, Mencia argues that the district court abused its dis-
cretion in declining to strike Dr. Silverman’s statement during
cross-examination that violating Section 456.44 carries criminal
penalties. We disagree. When defense counsel asked, “where the
statute provides for a criminal penalty, any sort of jail time,” the
district court sustained the government’s objection on relevance
grounds. When defense counsel continued and asked whether the
statute is “enforced by the Board of Medicine,” Dr. Silverman re-
sponded that “it was my understanding there were criminal penal-
ties. I don’t know specifically what they were.” The defense then
objected to Dr. Silverman’s answer and moved to strike because it
was “an incorrect statement of the law.” Instead of sustaining the
objection, the court asked the government to stipulate that there
are no criminal penalties and the government responded that it was
not aware of anything in Section 456.44 that defines a violation as
a misdemeanor, felony, or anything else.
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24                     Opinion of the Court                18-13967

       The district court did not err in resolving Mencia’s objection
to his own question. Although the government argues that the in-
vited error doctrine prevents Mencia from raising this issue on ap-
peal, see United States v. Sarras, 575 F.3d 1191, 1216 (11th Cir.
2009), we need not decide that point here. Even if the district court
erred by declining to strike this allegedly erroneous portion of Dr.
Silverman’s testimony, that error was harmless. See United States
v. Frediani, 790 F.3d 1196, 1202 (11th Cir. 2015). Under the harm-
less error standard, we need not reverse a conviction because of
evidentiary error when “the error had no substantial influence on
the outcome and sufficient evidence uninfected by error supports
the verdict.” Id. (quoting United States v. Hands, 184 F.3d 1322,
1329 (11th Cir. 1999)).
       That is the case here. To convict Mencia under Section 846,
the government needed to prove that Mencia conspired to distrib-
ute a controlled substance in violation of Section 841(a)(1)—that is,
for “other than legitimate medical purposes” or outside “the usual
course of professional practice.” Joseph, 709 F.3d at 1102 (quoting
Ignasiak, 667 F.3d at 1228). To do so, the government called Dr.
Silverman to testify. Although Dr. Silverman testified that he be-
lieved a state law defining the standard of medical practice carried
criminal penalties, the existence of criminal penalties under that
law is immaterial to whether Mencia’s actions comport with the
standard that law sets. On top of that, Dr. Silverman’s testimony
was not necessary to establish whether Mencia’s actions were con-
sistent with “accepted standards of professional practice”—lay
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18-13967                Opinion of the Court                        25

testimony and other evidence work just as well. See id. at 1103.
And on that front, the government introduced overwhelming evi-
dence that Mencia conspired to distribute controlled substances for
“other than legitimate medical purposes” or outside “the usual
course of professional practice.” Id. at 1102 (quoting Ignasiak, 667
F.3d at 1228). For example, several witnesses testified that there
was no logical connection between the medical conditions Mencia
treated and the opioids he prescribed; three of Mencia’s co-con-
spirators testified at length that he instructed them to sell medically
unnecessary, pre-signed prescriptions for cash; Marrero testified
that many of Mencia’s patients displayed obvious signs of drug-
seeking behavior and that their patient files were incomplete, often
missing standard urine tests, MRIs, and x-rays; and the government
introduced undercover DEA recordings in which Mencia pre-
scribed controlled substances without conducting physical exami-
nations of patients. Taken together, any error in failing to strike the
allegedly erroneous portion of Dr. Silverman’s testimony was
harmless; it “had no substantial influence on the outcome and suf-
ficient evidence uninfected by error supports the verdict.” Frediani,
790 F.3d at 1202 (quoting Hands, 184 F.3d at 1329).
       Third, Mencia argues that the government improperly im-
plied the existence of additional evidence not before the jury by
asking Dr. Warfield about a previous inconsistent statement.
Again, we disagree. Specifically, the prosecutor asked: “I believe
what you told me was that under no circumstance would it be
within the scope of professional practice to give a medical assistant
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26                     Opinion of the Court                 18-13967

with a presigned prescription for them to fill out at their discretion
for controlled two (sic) substances. Do you agree with that?” “It is
hornbook law that evidence of prior inconsistent statements of a
witness may be admitted to impeach that witness.” United States
v. Sisto, 534 F.2d 616, 622 (5th Cir. 1976). “The prior statements
may have been oral and unsworn, and the making of the previous
statements may be drawn out in cross-examination of the witness
himself.” Id. (quotation marks and citation omitted). For her part,
Dr. Warfield had an opportunity to answer––she responded that
she had said only that she “thought those medical assistants were
practicing medicine without a license, and they in no way should
have been given blank prescriptions to prescribe opiates to these
patients.” And the court correctly instructed the jury in response to
Mencia’s objection to this question that “what the lawyers say isn’t
evidence. The answers are evidence.” The district court did not
abuse its discretion in ruling on Mencia’s objection.
 2.    Dr. Silverman’s and Dr. Sullivan’s Methodologies, Qualifi-
                    cation, and Disclosures
        Mencia next argues that the court abused its discretion in al-
lowing Drs. Silverman and Sullivan to testify as experts because (1)
the court should have conducted Daubert hearings before qualify-
ing them as experts, and Dr. Silverman’s methodology was not suf-
ficiently reliable; and (2) Dr. Silverman’s disclosures were insuffi-
cient, and the untimeliness of the government’s disclosures preju-
diced the defense. We address each argument in turn.
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18-13967                Opinion of the Court                          27

        First, the district court did not abuse its discretion in declin-
ing to conduct Daubert hearings. In Daubert v. Merrell Dow Phar-
maceuticals, Inc., and its progeny, the Supreme Court explained
the requirements for expert testimony to be admissible under Fed-
eral Rule of Evidence 702. 509 U.S. 579, 589–94 (1993). Such testi-
mony is admissible if the expert is qualified, the expert’s methodol-
ogy is reliable, and the testimony assists the trier of fact. City of
Tuscaloosa v. Harcros Chems., Inc., 158 F.3d 548, 562 (11th Cir.
1998) (citation omitted). When assessing methodology, courts
should consider, where applicable, “whether it can be (and has
been) tested,” “whether the theory or technique has been subjected
to peer review and publication,” “the known or potential rate of
error, . . . and the existence and maintenance of standards control-
ling the technique’s operation,” and “general acceptance.” Daub-
ert, 509 U.S. at 593–94 (citation omitted). But that inquiry is “a flex-
ible one.” Id. at 594. If an expert’s methodology is based “solely or
primarily on experience, then the witness must explain how that
experience leads to the conclusion reached, why that experience is
a sufficient basis for the opinion, and how that experience is reliably
applied to the facts.” Fed. R. Evid. 702 advisory committee’s note
to 2000 amends.
        In Azmat, we held that the district court did not abuse its
discretion in allowing expert testimony where the government de-
tailed the “federal and state medical guidelines, literature from na-
tional organizations, published journal articles, and [medical] text-
books” that the expert relied on in reaching his conclusions. 805
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28                      Opinion of the Court                 18-13967

F.3d at 1042. The government had also explained the expert’s
“method of reviewing patient files, which involved [the expert]
weighing [the defendant’s] decisions against the standards articu-
lated in the” medical texts that the expert relied on and the expert
“exercising his judgment as an experienced medical practitioner to
reach conclusions” as to the defendant’s conduct. Id. Because the
expert “relied on published sources generally accepted by the med-
ical community in defining the applicable standard of care,” the dis-
trict court did not abuse its discretion in admitting the testimony.
Id.
       To determine whether an expert’s methodology meets
Daubert’s standards, a district court can, but is not required to, con-
duct a Daubert hearing. See City of Tuscaloosa, 158 F.3d at 564
n.21. Daubert hearings are particularly helpful “in complicated
cases involving multiple expert witnesses[.]” Id. “A district court
should conduct a Daubert inquiry when the opposing party’s mo-
tion for a hearing is supported by ‘conflicting medical literature and
expert testimony.’” United States v. Hansen, 262 F.3d 1217, 1234
(11th Cir. 2001) (quoting Tanner v. Westbrook, 174 F.3d 542, 546
(5th Cir. 1999)).
      Here, Dr. Silverman’s experience includes a medical degree,
board certifications in pain management and addiction, more than
twenty years of pain management in Florida, authorship of numer-
ous peer-reviewed articles and a textbook on pain management,
and a history of assisting state and federal investigations into the
opioid crisis in Florida. He testified that his practice, training,
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18-13967               Opinion of the Court                       29

experience, and education have made him familiar with the “ac-
cepted scope of professional practice when it comes to pain man-
agement and opioid prescriptions.” Based on those qualifications,
the government tendered him as an expert in pain management
and addiction “with the ability to opine on what is and what is not,
in his opinion, within the accepted scope of professional practice
and whether medications are issued for a legitimate medical pur-
pose.”
       Dr. Silverman applied that experience to the evidence to
form his opinions. He reviewed patient files that the government
selected for him, a list of the controlled substances that were pre-
scribed to Dr. Mencia’s patients, applicable Florida statutes, appli-
cable federal regulations, and the confidential informant videos and
transcripts. He then applied his experience and knowledge to that
data to determine that Mencia was acting outside the scope of pro-
fessional practice in prescribing certain controlled substances with-
out a legitimate medical purpose.
       The district court did not abuse its discretion in admitting
that testimony. The district court was required to assess Dr. Silver-
man’s methodology before admitting his testimony and the gov-
ernment provided ample evidence of his qualifications and the re-
sources that he relied on in coming to his opinions. Like in Azmat,
those resources included applicable law and “published sources
generally accepted by the medical community in defining the ap-
plicable standard of care.” 805 F.3d at 1042.
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30                      Opinion of the Court                 18-13967

        The court was not required to conduct a Daubert hearing,
and the defense did not support its objection with conflicting med-
ical literature or expert testimony. See Hansen, 262 F.3d at 1234.
Mencia argues that Dr. Warfield’s conflicting opinions should have
necessitated a Daubert hearing, but he did not make that argument
in his motion to exclude Dr. Silverman’s expert testimony or in his
objection. Instead, he merely argued that Dr. Silverman’s method-
ology was insufficiently reliable. Under such a deferential standard
of review, that is insufficient reasoning for this Court to reverse the
district court’s decision. Because the district court’s decision not to
hold a Daubert hearing was based on the implicit decision that Dr.
Silverman’s methodology was reliable, the district court did not
abuse its discretion in making that determination, either.
       Second, the district court did not abuse its discretion in over-
ruling Mencia’s objection to the government’s pre-trial disclosures
as incomplete or untimely. At the defendant’s request, the govern-
ment must give a defendant a written summary of any expert tes-
timony it intends to use, which “must describe the witness’s opin-
ions, the bases and reasons for those opinions, and the witness’s
qualifications.” Fed. R. Crim. P. 16(a)(1)(G). In the absence of a
scheduling order, this Court has not stated a bright-line rule for
how far in advance of trial the government should provide a sum-
mary. But this Court has held that a summary provided “almost
one month before trial” was sufficient, even when the identity of
the proposed expert changed weeks later. See United States v.
Chalker, 966 F.3d 1177, 1193 (11th Cir. 2020). In any event, this
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18-13967               Opinion of the Court                        31

Court “will not reverse a conviction based on a Rule 16 expert dis-
closure violation unless the violation prejudiced the defendant’s
substantial rights.” Id. (quoting United States v. Stahlman, 934 F.3d
1199, 1222 n.10 (11th Cir. 2019)). A defendant must establish that
the violation of Rule 16 “adversely affected their ability to present
a defense.” United States v. Chastain, 198 F.3d 1338, 1348 (11th Cir.
1999).
       There is no reversible error in this case. The government
disclosed Drs. Silverman and Sullivan about one month after Men-
cia requested its disclosures, thirteen and twelve days before trial,
respectively. Even assuming for the sake of argument that those
disclosures came too close to trial, we cannot say the timing ad-
versely affected Mencia’s ability to present a defense. The govern-
ment agreed to a trial continuance to allow Mencia more time to
prepare, but he did not ask for one. See United States v. Rivera, 944
F.2d 1563, 1566 (11th Cir. 1991) (“if Rivera had, in fact, been preju-
diced by the delayed disclosure . . . he should have moved for a
continuance”). And Mencia presented a rebuttal expert witness,
Dr. Warfield, whose opinions directly conflicted with Dr. Silver-
man’s opinions. He also had time to acquire Dr. Silverman’s Flor-
ida Department of Health disciplinary records to use during cross-
examination.
       The disclosures were also sufficient. In its disclosures, the
government summarized Dr. Silverman’s testimony as opining
“that the defendant prescribed or caused to be prescribed Schedule
II substances outside the course of professional practice and not for
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32                         Opinion of the Court                       18-13967

a legitimate medical purpose.” He would additionally opine on
Mencia’s conduct in the undercover recordings, concluding that
the conduct was “outside the scope of professional practice.” Men-
cia argues that this description did not encompass Dr. Silverman’s
testimony that Mencia’s conduct in pre-signing prescriptions and
allowing medical assistants to see patients alone before merely
signing a prescription fell outside the scope of professional practice.
But those opinions were encompassed by the government’s sum-
mary. Whether Mencia prescribed or caused to be prescribed con-
trolled substances outside the course of professional practice en-
compasses pre-signing prescriptions and signing them without see-
ing patients. And the undercover recordings included medical as-
sistants seeing patients alone and giving them prescriptions with-
out consulting with Mencia. But even if the government’s sum-
mary was too vague, it again did not impair Mencia’s substantial
rights because he was able to present Dr. Warfield’s conflicting tes-
timony on the same issues. 3

3 Mencia argues for the first time on appeal that Dr. Sullivan was not qualified
to testify as an expert. Mencia did not object to Dr. Sullivan’s testimony on
that ground––the defense argued only that her methodology had not been suf-
ficiently vetted by the district court. Accordingly, we review that argument
for plain error, Fed. R. Crim. P. 52(b), and conclude that the district court did
not plainly err in allowing Dr. Sullivan’s testimony.
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18-13967               Opinion of the Court                        33

                      C.     Constitutionality

       Mencia also argues that the Controlled Substances Act is un-
constitutionally vague as applied to physicians. He contends that,
because no statute or regulation defines the standard of care against
which his conduct can be compared, that standard was defined by
“unqualified government experts” and Mencia was convicted
“based on this nebulous definition of standard of care.”
        When “a vagueness challenge does not involve the First
Amendment, the analysis must be as applied to the facts of the
case.” United States v. Wayerski, 624 F.3d 1342, 1347 (11th Cir.
2010). Mencia has not raised a First Amendment challenge. Accord-
ingly, the question for this Court is whether the Act “fails to pro-
vide people of ordinary intelligence a reasonable opportunity to
understand what conduct it prohibits’ or ‘it authorizes or even en-
courages arbitrary and discriminatory enforcement.’” Id. (quoting
Hill v. Colorado, 530 U.S. 703, 732 (2000)). To establish that the Act
is unconstitutionally vague, Mencia must overcome the “strong
presumption that statutes passed by Congress are valid.” Id.
        In United States v. Collier, a physician appealed his convic-
tion under Section 841(a)(1) for distribution of methadone while
acting outside the usual course of professional practice. 478 F.2d
268, 270 (5th Cir. 1973). This Court rejected the physician’s argu-
ment that the phrase “in the course of his professional practice” did
not give physicians notice as to what conduct violates the statute.
Id. at 270–72. We held that the statute necessarily gave physicians
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34                     Opinion of the Court                 18-13967

“a certain latitude of available options,” because “the physician
must make a professional judgment as to whether a patient’s con-
dition is such that a certain drug should be prescribed.” Id. at 272.
And that judgment is what physicians must routinely exercise in
prescribing controlled substances. Id. Accordingly, the Act’s prohi-
bition of distributing controlled substances outside the course of
professional practice is not unconstitutionally vague; it is a clear
reference to the judgment calls that physicians routinely make. Id.
        Here, Mencia makes an argument nearly identical to the de-
fendant’s argument in Collier. He argues that the lack of a statute
or regulation defining the baseline standard of care renders the Act
unconstitutionally vague as applied to physicians. But this Court
already held that the phrase “in the course of his professional prac-
tice” is not unconstitutionally vague and does not require a statu-
tory or regulatory definition because it is a necessarily fact-inten-
sive inquiry in which physicians must exercise their professional
judgment. Id. And Mencia fails to distinguish his argument from
the defendant’s argument in Collier. Instead, he argues that his case
is different because he was not acting as a drug pusher. But that is
exactly the question that the Act seeks to answer––when does a
physician stop acting as a doctor and start acting as a “drug pusher.”
The answer under the Act is when he prescribes controlled sub-
stances outside the course of his professional practice or without a
legitimate medical purpose. Because this Court has already re-
jected the exact argument that Mencia raises, we affirm.
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18-13967                 Opinion of the Court                          35

                       D.      Jury Instructions

       Finally, Mencia argues that the “good faith defense” instruc-
tion given by the district court does not comply with Ruan. How-
ever, Mencia omits from his supplemental brief the fact that he re-
quested the jury instructions and the district court granted his re-
quest. And “where a party expressly accepts,” or in this case re-
quests, “a jury instruction, such action constitutes invited error”
and “serve[s] to waive [his] right to challenge the accepted instruc-
tion on appeal.” United States v. Silvestri, 409 F.3d 1311, 1337 (11th
Cir. 2005). Regardless, the instructions given by the district court
do not constitute reversible error even viewed in light of Ruan. As
Mencia failed to object to the sufficiency of the challenged jury in-
structions at the district court, we review for plain error.
1.     Mencia waived his right to challenge the good faith instruc-
                    tion as he requested it
        Mencia’s argument is based principally on his contention
that in Ruan, “the Supreme Court [ruled] the ‘good faith’ jury in-
struction to be error.” This is a misstatement of the Court’s holding
and is irrelevant in any event because any error associated with the
instruction was invited.
       In Ruan, the defendants were physicians convicted of violat-
ing 21 U.S.C. § 841(a)(1) by unlawfully dispensing opioid prescrip-
tions. 142 S. Ct. at 2375. Section 841(a) makes it a federal crime,
“[e]xcept as authorized[,] . . . for any person knowingly or inten-
tionally . . . to manufacture, distribute, or dispense . . . a con-trolled
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36                      Opinion of the Court                 18-13967

substance.” 21 U.S.C. § 841(a) (emphasis added). A licensed physi-
cian is authorized to prescribe certain controlled substances if she
issues that prescription “for a legitimate medical purpose . . . acting
in the usual course of his professional practice.” 21 C.F.R. §
1306.04(a).
       One of the Ruan defendants requested a jury instruction re-
quiring the government to prove that he knew that his prescrip-
tions fell outside the scope of his prescribing authority. Ruan, 142
S. Ct. at 2375. The district court rejected that instruction, and this
Court affirmed, determining that the requested good faith instruc-
tion was an incorrect statement of the law because a doctor’s “sub-
jectiv[e] belie[f] that he is meeting a patient’s medical needs by pre-
scribing a controlled substance” is not a “complete defense” to a
Section 841 prosecution. Id. at 2376; United States v. Ruan, 966 F.3d
1101, 1166 (11th Cir. 2020) (“Whether the defendant acts in the
usual course of his professional practice must be evaluated based
on an objective standard, not a subjective standard”). The Supreme
Court, however, disagreed.
       Instead, the Supreme Court held that Section 841(a)’s
“knowingly or intentionally” mens rea applies to the “except as au-
thorized” clause of that statute, meaning a defendant physician’s
subjective intent could be a complete defense to the crime. Ruan,
142 S. Ct. at 2375. The Court did not evaluate whether the district
court’s jury instructions substantially covered that subjective intent
requirement or whether any instructional error was harmless, leav-
ing those determinations for this Court on remand. Id. at 2382.
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18-13967               Opinion of the Court                        37

        The Court in Ruan did not hold, as Mencia claims, that re-
versal was warranted there because of the inclusion of the good
faith instruction. Instead, the failure to include the instruction—as
well as our holding that a doctor’s subjective belief that he is meet-
ing a patient’s medical needs by prescribing a controlled substance
is not a complete defense to a Section 841 prosecution—formed the
basis of the Court’s reversal. Consistent with the Court’s holding
in Ruan, the good faith instruction in this case required the jury to
consider Mencia’s subjective intent in determining whether he had
a “good faith reasonable belief” that the distribution of controlled
substances was unauthorized. Regardless, as Mencia himself re-
quested that instruction, it cannot serve as the basis for a reversal
of his conviction as he “waive[d] [his] right to challenge the ac-
cepted instruction on appeal.” Silvestri, 409 F.3d 1311, 1337 (11th
Cir.2005).
 2.    The jury instructions for the conspiracy count sufficiently
       conveyed the mens rea requirement for unauthorized dis-
                                tribution
       Similarly, the jury instruction for the conspiracy count was
not erroneous under Ruan or, at least, not plain error under that
decision. The instruction communicated that the government
must prove beyond a reasonable doubt that the physician knew
that the prescriptions were not “authorized.”
        The instruction stated that Mencia could be found guilty
only if the Government proved beyond a reasonable doubt that (1)
he and another person “in some way agreed to try to accomplish a
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shared and unlawful plan to distribute or dispense a con-trolled
substance, outside the scope of professional practice and not for a
legitimate medical purpose”; (2) Mencia “knew the unlawful pur-
pose of the plan and willfully joined in it”; and (3) the purpose of
the plan, “was to distribute or dispense a controlled substance, out-
side the scope of professional practice and not for a legitimate med-
ical purpose.” This instruction thus required the government to
prove that Mencia knew that the prescriptions he had written were
unauthorized or, in other words, that they were outside the scope
of professional practice and not for a legitimate medical purpose.
Had he not known that the prescriptions were unauthorized, he
could not have known the “unlawful purpose of the plan” and the
second element would not have been satisfied.
       The conspiracy charge was the sole count for which Mencia
was ultimately convicted. Further, as explained above, the argu-
ment relating to the sufficiency of the good faith instruction cannot
be the basis for reversible error, and he does not challenge the lan-
guage of any other jury instructions. Accordingly, Mencia’s argu-
ment that the jury instructions at his trial require us to vacate his
conviction fails.
                      IV.    CONCLUSION

        The government provided sufficient evidence of Mencia’s
guilt, the district court properly admitted the expert testimony, the
Act is not unconstitutionally vague as applied to physicians, and the
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18-13967              Opinion of the Court                     39

jury instructions are acceptable in light of Ruan. Accordingly, we
affirm.