# Buprenorphine Basics
## Pharmacology

Buprenorphine is a semi-synthetic opioid derived from thebaine. Structurally, buprenorphine is different from other opioids in that it contains an N-CPM group.

### Pharmacodynamics

Buprenorphine is most often classified as a "partial opioid agonist," however it's activity is more nuanced than that. This "partial agonist" description comes from the previous belief that buprenorphine is a partial agonist at μ opioid receptors as well as being an antagonist at δ and κ opioid receptors. It is the only FDA-approved drug with known activity at the ORL-1 receptor, at which it is an agonist.

### Pharmacokinetics
## Buprenorphine & Oral Morphine Equivalents (OMEs)

Due to its unique mechanism of action, it is not appropriate to design therapeutic regimens based on the OMEs of a given buprenorphine formulation. However, for knowledge's sake let's discuss how one would go about converting buprenorphine to OMEs.
The first step to doing this is to consider the bioavailability of each of the buprenorphine formulations.

## Perioperative Management of Buprenorphine

A frequently asked question from primary teams and surgeons: what do we do with this patient's buprenorphine?
The American Society of Regional Anesthesia & Pain Medicine published a review regarding the perioperative management of buprenorphine in 2021. In this review, they recommended against the routine perioperative discontinuation of buprenorphine. Generally, patients receiving 16mg/day of buprenorphine or less, can be maintained on buprenorphine and treated with PRN "traditional" full mu opioid agonists for breakthrough pain, though these patients may require higher doses of the "traditional" full mu opioid agonists compared to patients not taking buprenorphine. Multimodal pain management strategies should always be utilized. If a patient is taking buprenorphine for OUD, the goal should be to taper the patient off of any other opioids aside from buprenorphine prior to discharge.

### Several organizations have published their own guidelines or algorithms on the perioperative management of buprenorphine:

* UCSF Guideline for the Perioperative Management of Buprenorphine Algorithm
** Notably, this guideline advises that patients receiving 8mg buprenorphine per day or more may need to be tapered, compared to expert opinion and other guidelines that suggest a higher threshold of 16mg/day.
* VA PBM Guidelines for the Perioperative Management of Buprenorphine Algorithm
** Essentially the same as the UCSF algorithm, but threshold for high vs. low buprenorphine is 16mg/day.
* VA PBM Perioperative Pain Management Guidance for Patients on Chronic Buprenorphine Therapy Undergoing Elective or Emergent Procedures full guidance document

# Buprenorphine Formulations

Buprenorphine comes in several different formulations, all of which are considered "long-acting" except for the IV injection. Regardless which formulation is chosen, it is important to educate patients and providers about the administration technique of the chosen formulation. Furthermore, if initiating buprenorphine inpatient, it is wise to check with nursing staff and gauge their familiarity with the buprenorphine product. Nursing staff education on buprenorphine may be necessary if they are unfamiliar.
In patients where there is a large "psychological" component to their pain, an oral medication may be more effective compared to buprenorphine transdermal. Patients are conditioned to expect pain relief after taking a medication, hence why a twice-daily buccal film or several-times-a-day SL tablet/film may be perceived as more effective for pain relief by the patient compared to a once-weekly transdermal patch. This is why sometimes patients report analgesia within minutes of taking a medication even when it is known that the absorption and onset of effects take hours – it isn’t that the medication started working sooner, it’s just psychology!

## Buprenorphine Buccal Film

Practice Pearl: You may find it helpful to include the following directions in inpatient orders for buprenorphine buccal films:
    Do not cut or tear the film. With a dry finger, place yellow side of film against the inside of cheek - press and hold in place for 5 seconds. Do not chew or swallow the film. Rinse water around teeth after fully dissolved (~30 minutes). Wait one hour after application before brushing teeth.

## Buprenorphine Transdermal Patch

See Also
* PCNOW Fast Fact # 268 - Low-Dose Buprenorphine Patch for Pain

## Buprenorphine Sublingual Tablet

The analgesic effects of buprenorphine SL tablets lasts approximately 6 to 8 hours. Patients who are prescribed buprenorphine or buprenorphine/naloxone SL tablets for opioid use disorder or complex opioid dependency usually take their buprenorphine as one dose daily. If a patient who is prescribed buprenorphine or buprenorphine/naloxone SL tablets is in need of acute pain management, consider maintaining the same daily dose of buprenorphine but administering it in divided doses. For example, a patient taking buprenorphine 16mg/naloxone 4mg once daily can be transitioned to buprenorphine 4mg/naloxone 1mg SL Q6H -- this would ensure patient is receiving the same total daily dose of buprenorphine (16mg/day) but at dosing intervals that will better address the acute pain.

## Buprenorphine Intravenous Injection
# Further Reading

PCNOW Fast Facts:
* PCNOW Fast Fact # 457 - Buprenorphine Initiation – Low Dose Methods
* PCNOW Fast Fact # 441 - Sublingual Buprenorphine Initiation: The Traditional Method
* PCNOW Fast Fact # 221 - Treatment of Pain in Patients Taking Buprenorphine for Opioid Use Disorders

# References

* ↑ Kohan, Lynn; Potru, Sudheer; Barreveld, Antje M.; Sprintz, Michael; Lane, Olabisi; Aryal, Anuj; Emerick, Trent; Dopp, Anna; Chhay, Sophia; Viscusi, Eugene (2021-10-01). "Buprenorphine management in the perioperative period: educational review and recommendations from a multisociety expert panel". Regional Anesthesia & Pain Medicine. 46 (10): 840–859. doi:10.1136/rapm-2021-103007. ISSN 1098-7339. PMID 34385292.