Amlodipine and Benazepril

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# Black Box Warning

# Overview
Amlodipine and Benazepril is a combination of dihydropyridine calcium channel blocker (DHP CCB) and an angiotensin converting enzyme (ACE) inhibitor that is FDA approved for the {{{indicationType}}} of hypertension. There is a Black Box Warning for this drug as shown here.  Common adverse reactions include cough and edema.

# Adult Indications and Dosage

## FDA-Labeled Indications and Dosage (Adult)
- Dosing Information
- The recommended initial dose of Lotrel is one capsule of amlodipine 2.5 mg/benazepril 10 mg orally once daily.
- It is usually appropriate to begin therapy with Lotrel only after a patient has either (a) failed to achieve the desired antihypertensive effect with amlodipine or benazepril monotherapy, or (b) demonstrated inability to achieve adequate antihypertensive effect with amlodipine therapy without developing edema.
- The antihypertensive effect of Lotrel is largely attained within 2 weeks. If blood pressure remains uncontrolled, the dose may be titrated up to amlodipine 10 mg/benazepril 40 mg once daily. The dosing should be individualized and adjusted according to the patients clinical response.
- Amlodipine is an effective treatment of hypertension in once-daily doses of 2.5-10 mg while benazepril is effective in doses of 10-80 mg. In clinical trials of amlodipine/benazepril combination therapy using amlodipine doses of 2.5-10 mg and benazepril doses of 10-40 mg, the antihypertensive effects increased with increasing dose of amlodipine in all patient groups, and the effects increased with increasing dose of benazepril in nonblack groups.

## Off-Label Use and Dosage (Adult)

### Guideline-Supported Use
There is limited information regarding Off-Label Guideline-Supported Use of Amlodipine and Benazepril in adult patients.

### NonGuideline-Supported Use
- Dosing Information
- Benazepril 10 mg plus amlodipine 5 mg once daily.
- Dosing Information
- Benazepril 20 milligrams (mg) plus amlodipine 5 mg.
- Dosing Information
- Amlodipine 5 mg-benazepril 20 mg
There is limited information regarding Off-Label NonGuideline-Supported Use of Amlodipine and Benazepril in adult patients.

# Pediatric Indications and Dosage

## FDA-Labeled Indications and Dosage (Pediatric)
There is limited information regarding FDA-Labeled Use of Amlodipine and Benazepril in pediatric patients.

## Off-Label Use and Dosage (Pediatric)

### Guideline-Supported Use
There is limited information regarding Off-Label Guideline-Supported Use of Amlodipine and Benazepril in pediatric patients.

### NonGuideline-Supported Use
There is limited information regarding Off-Label NonGuideline-Supported Use of Amlodipine and Benazepril in pediatric patients.

# Contraindications
- Do not co-administer aliskiren with angiotensin receptor blockers, ACE inhibitors, including Lotrel in patients with diabetes.
- Lotrel is contraindicated in patients with a history of angioedema, with or without previous ACE inhibitor treatment, or patients who are hypersensitive to benazepril, to any other ACE inhibitor, to amlodipine, or to any of the excipients of Lotrel.

# Warnings

### Precautions
- Anaphylactoid and Possibly Related Reactions
- Presumably because angiotensin-converting enzyme inhibitors affect the metabolism of eicosanoids and polypeptides, including endogenous bradykinin, patients receiving ACE inhibitors (including Lotrel) may be subject to a variety of adverse reactions, some of them serious. These reactions usually occur after one of the first few doses of the ACE inhibitor, but they sometimes do not appear until after months of therapy. Black patients receiving ACE inhibitors have a higher incidence of angioedema compared to nonblacks.
- Head and Neck Angioedema: Angioedema of the face, extremities, lips, tongue, glottis, and larynx has been reported in patients treated with ACE inhibitors. In U.S. clinical trials, symptoms consistent with angioedema were seen in none of the subjects who received placebo and in about 0.5% of the subjects who received benazepril. Angioedema associated with laryngeal edema can be fatal. If laryngeal stridor or angioedema of the face, tongue, or glottis occurs, discontinue treatment with Lotrel and treat  immediately. When involvement of the tongue, glottis, or larynx appears likely to cause airway obstruction, appropriate therapy, e.g., administer subcutaneous epinephrine injection 1:1000 (0.3-0.5 mL), promptly.
- Intestinal Angioedema: Intestinal angioedema has been reported in patients treated with ACE inhibitors. These patients presented with abdominal pain (with or without nausea or vomiting); in some cases there was no prior history of facial angioedema and C-1 esterase levels were normal. The angioedema was diagnosed by procedures including abdominal CT scan or ultrasound, or at surgery, and symptoms resolved after stopping the ACE inhibitor. Intestinal angioedema should be included in the differential diagnosis of patients on ACE inhibitors presenting with abdominal pain.
- Anaphylactoid Reactions During Desensitization: Two patients undergoing desensitizing treatment with hymenoptera venom while receiving ACE inhibitors sustained life-threatening anaphylactoid reactions. In the same patients, these reactions were avoided when ACE inhibitors were temporarily withheld, but they reappeared upon inadvertent rechallenge.
- Anaphylactoid Reactions During Membrane Exposure: Anaphylactoid reactions have been reported in patients dialyzed with high-flux membranes and treated concomitantly with an ACE inhibitor. Anaphylactoid reactions have also been reported in patients undergoing low-density lipoprotein apheresis with dextran sulfate absorption.
- Increased Angina and/or Myocardial Infarction
- Worsening angina and acute myocardial infarction can develop after starting or increasing the dose of amlodipine, particularly in patients with severe obstructive coronary artery disease.
- Patients with Aortic and Mitral Valve Stenosis, Obstructive Hypertrophic Cardiomyopathy
- As with all other vasodilators, special caution is required when using amlodipine in patients suffering from aortic or mitral stenosis, or obstructive hypertrophic cardiomyopathy.
- Hypotension
- Lotrel can cause symptomatic hypotension. Symptomatic hypotension is most likely to occur in patients who have been volume or salt depleted as a result of diuretic therapy, dietary salt restriction, dialysis, diarrhea, or vomiting. Volume and/or salt depletion should be corrected before starting therapy with benazepril. If hypotension occurs, the patient should be placed in the supine position and if necessary given physiological saline i.v. Treatment with benazepril can be continued once blood pressure and volume have returned to normal.
- In patients with congestive heart failure, with or without associated renal insufficiency, ACE inhibitor therapy may cause excessive hypotension, which may be associated with oliguria, azotemia, and (rarely) with acute renal failure and death. In such patients, start Lotrel therapy under close medical supervision; follow closely for the first 2 weeks of treatment and whenever the dose of the benazepril component is increased or a diuretic is added or its dose increased.
- Symptomatic hypotension is also possible in patients with severe aortic stenosis.
- Fetal Toxicity
- Pregnancy Category D
- Use of drugs that act on the renin-angiotensin system during the second and third trimesters of pregnancy reduces fetal renal function and increases fetal and neonatal morbidity and death. Resulting oligohydramnios can be associated with fetal lung hypoplasia and skeletal deformations. Potential neonatal adverse effects include skull hypoplasia, anuria, hypotension, renal failure, and death. When pregnancy is detected, discontinue Lotrel as soon as possible.
- Hepatitis and Hepatic Failure
- There have been rare reports of predominantly cholestatic hepatitis and isolated cases of acute liver failure, some of them fatal, in patients on ACE inhibitors. The mechanism is not understood. Patients receiving ACE inhibitors who develop jaundice or marked elevation of hepatic enzymes should discontinue the ACE inhibitor and be kept under medical surveillance.
- Impaired Renal Function
- Monitor renal function periodically in patients treated with Lotrel. Changes in renal function, including acute renal failure, can be caused by drugs that affect the renin-angiotensin system. Patients whose renal function may depend in part on the activity of the renin-angiotensin system (e.g., patients with renal artery stenosis, severe heart failure, post-myocardial infarction or volume depletion) or who are on NSAIDS or angiotensin receptor blockers may be at particular risk of developing acute renal failure on Lotrel. Consider withholding or discontinuing therapy in patients who develop a clinically significant decrease in renal function on Lotrel.
- Hyperkalemia
- Monitor serum potassium periodically in patients receiving Lotrel. Drugs that affect the renin-angiotensin system can cause hyperkalemia. Risk factors for the development of hyperkalemia include renal insufficiency, diabetes mellitus, and the concomitant use of potassium-sparing diuretics, potassium supplements, and/or potassium-containing salt substitutes. In U.S. placebo-controlled trials of Lotrel, hyperkalemia (serum potassium at least 0.5 mEq/L greater than the upper limit of normal) not present at baseline occurred in approximately 1.5% of hypertensive patients receiving Lotrel. Increases in serum potassium were generally reversible.
- Cough
- Presumably due to the inhibition of the degradation of endogenous bradykinin, persistent nonproductive cough has been reported with all ACE inhibitors, generally resolving after discontinuation of therapy. Consider ACE inhibitor-induced cough in the differential diagnosis of cough.
- Surgery/Anesthesia
- In patients undergoing surgery or during anesthesia with agents that produce hypotension, benazepril will block the angiotensin II formation that could otherwise occur secondary to compensatory renin release. Hypotension that occurs as a result of this mechanism can be corrected by volume expansion.

# Adverse Reactions

## Clinical Trials Experience
- Because clinical trials are conducted under widely varying conditions, adverse reaction rates observed in the clinical trials of a drug cannot be directly compared to rates in the clinical trials of another drug and may not reflect the rates observed in practice. The adverse reaction information from clinical trials does, however, provide a basis for identifying the adverse events that appear to be related to drug use and for approximating rates.
- Lotrel has been evaluated for safety in over 2,991 patients with hypertension; over 500 of these patients were treated for at least 6 months, and over 400 were treated for more than 1 year.
- In a pooled analysis of 5 placebo-controlled trials involving Lotrel doses up to 5/20, the reported side effects were generally mild and transient, and there was no relationship between side effects and age, sex, race, or duration of therapy. Discontinuation of therapy due to side effects was required in approximately 4% of patients treated with Lotrel and in 3% of patients treated with placebo.
- The most common reasons for discontinuation of therapy with Lotrel in these studies were cough and edema (including angioedema).
- The peripheral edema associated with amlodipine use is dose-dependent. When benazepril is added to a regimen of amlodipine, the incidence of edema is substantially reduced.
- The addition of benazepril to a regimen of amlodipine should not be expected to provide additional antihypertensive effect in African-Americans. However, all patient groups benefit from the reduction in amlodipine-induced edema.
- The side effects considered possibly or probably related to study drug that occurred in these trials in more than 1% of patients treated with Lotrel are shown in the table below. Cough was the only adverse event with at least possible relationship to treatment that was more common on Lotrel (3.3%) than on placebo (0.2%).
- Edema refers to all edema, such as dependent edema, angioedema, facial edema.
- The incidence of edema was greater in patients treated with amlodipine monotherapy (5.1%) than in patients treated with Lotrel (2.1%) or placebo (2.2%).
- Other side effects considered possibly or probably related to study drug that occurred in U.S. placebo-controlled trials of patients treated with Lotrel or in postmarketing experience were the following:
Asthenia and fatigue.
Insomnia, nervousness, anxiety, tremor, and decreased libido.
Flushing, hot flashes, rash, skin nodule, and dermatitis.
Dry mouth, nausea, abdominal pain, constipation, diarrhea, dyspepsia, and esophagitis.
Neutropenia
Hypokalemia.
Back pain, musculoskeletal pain, cramps, and muscle cramps.
Pharyngitis.
Sexual problems such as impotence, and polyuria.
- Monotherapies of benazepril and amlodipine have been evaluated for safety in clinical trials in over 6,000 and 11,000 patients, respectively. The observed adverse reactions to the monotherapies in these trials were similar to those seen in trials of Lotrel.

## Postmarketing Experience
- Because these reactions are reported voluntarily from a population of uncertain size, it is not always possible to reliably estimate their frequency or establish a causal relationship to drug exposure.
- In postmarketing experience with benazepril, there have been rare reports of Stevens-Johnson syndrome, pancreatitis, hemolytic anemia, pemphigus, thrombocytopenia, paresthesia, dysgeusia, orthostatic symptoms and hypotension, angina pectoris and arrhythmia, pruritus, photosensitivity reaction, arthralgia, arthritis, myalgia, BUN increase, serum creatinine increased, renal impairment, impaired vision, agranulocytosis, neutropenia.
- Rare reports in association with use of amlodipine: gingival hyperplasia, tachycardia, jaundice, and hepatic enzyme elevations (mostly consistent with cholestasis severe enough to require hospitalization), leucocytopenia, allergic reaction, hyperglycemia, dysgeusia, hypoesthesia, paresthesia, syncope, peripheral neuropathy, hypertonia, visual impairment, diplopia, hypotension, vasculitis, rhinitis, gastritis, hyperhidrosis, pruritis, skin discoloration, urticaria, erythema multiform, muscle spasms, arthralgia, micturition disorder, nocturia, erectile dysfunction, malaise, weight decrease or gain.
- Other potentially important adverse experiences attributed to other ACE inhibitors and calcium channel blockers include: eosinophilic pneumonitis (ACE inhibitors) and gynecomastia (CCBs). Other infrequently reported events included chest pain, ventricular extrasystole, gout, neuritis, tinnitus, alopecia, upper respiratory tract infection, palpitations and somnolence.

# Drug Interactions
- Simvastatin
- Co-administration of simvastatin with amlodipine increases the systemic exposure of simvastatin. Limit the dose of simvastatin in patients on amlodipine to 20 mg daily.
- CYP3A4 Inhibitors
- Co-administration with CYP3A inhibitors (moderate and strong) results in increased systemic exposure to amlodipine and may require dose reduction. Monitor for symptoms of hypotension and edema when amlodipine is co-administered with CYP3A4 inhibitors to determine the need for dose adjustment.
- CYP3A4 Inducers
- No information is available on the quantitative effects of CYP3A4 inducers on amlodipine. Blood pressure should be monitored when amlodipine is co-administered with CYP3A4 inducers.
- Potassium Supplements and Potassium-Sparing Diuretics
- Benazepril can attenuate potassium loss caused by thiazide diuretics. Potassium-sparing diuretics (spironolactone, amiloride, triamterene, and others) or potassium supplements can increase the risk of hyperkalemia. If concomitant use of such agents is indicated, the patients serum potassium should be monitored frequently.
- Lithium
- Increased serum lithium levels and symptoms of lithium toxicity have been reported in patients receiving ACE inhibitors during therapy with lithium. When coadministering Lotrel and lithium, frequent monitoring of serum lithium levels is recommended.
- Gold
- Nitritoid reactions (symptoms include facial flushing, nausea, vomiting and hypotension) have been reported rarely in patients on therapy with injectable gold (sodium aurothiomalate) and concomitant ACE inhibitor therapy.
- Non-Steroidal Anti-Inflammatory Agents including Selective Cyclooxygenase-2 Inhibitors (COX-2 Inhibitors)
- In patients who are elderly, volume-depleted (including those on diuretic therapy), or with compromised renal function, co-administration of NSAIDs, including selective COX-2 inhibitors, with ACE inhibitors, including benazepril, may result in deterioration of renal function, including possible acute renal failure. These effects are usually reversible. Monitor renal function periodically in patients receiving benazepril and NSAID therapy.
- The antihypertensive effect of ACE inhibitors including benazepril, may be attenuated by NSAIDs.
- Antidiabetic agents
- In rare cases, diabetic patients receiving an ACE inhibitor (including benazepril) concomitantly with insulin or oral antidiabetics may develop hypoglycemia. Such patients should therefore be advised about the possibility of hypoglycemic reactions, and should be monitored accordingly.
- Dual Blockade of the Renin-Angiotensin System (RAS)
- Dual blockade of the RAS with angiotensin receptor blockers, ACE inhibitors, or aliskiren is associated with increased risks of hypotension, hyperkalemia, and changes in renal function (including acute renal failure) compared to monotherapy. Closely monitor blood pressure, renal function and electrolytes in patients on Lotrel and other agents that block the RAS.
- Do not co-administer aliskiren with Lotrel in patients with diabetes. Avoid use of aliskiren with Lotrel in patients with renal impairment (GFR <60 ml/min).

# Use in Specific Populations

### Pregnancy
Pregnancy Category (FDA):
- Pregnancy Category D
- Use of drugs that act on the renin-angiotensin system during the second and third trimesters of pregnancy reduces fetal renal function and increases fetal and neonatal morbidity and death. Resulting oligohydramnios can be associated with fetal lung hypoplasia and skeletal deformations. Potential neonatal adverse effects include skull hypoplasia, anuria, hypotension, renal failure, and death. When pregnancy is detected, discontinue Lotrel as soon as possible. These adverse outcomes are usually associated with use of these drugs in the second and third trimester of pregnancy. Most epidemiologic studies examining fetal abnormalities after exposure to antihypertensive use in the first trimester have not distinguished drugs affecting the renin-angiotensin system from other antihypertensive agents. Appropriate management of maternal hypertension during pregnancy is important to optimize outcomes for both mother and fetus.
- In the unusual case that there is no appropriate alternative to therapy with drugs affecting the renin-angiotensin system for a particular patient, apprise the mother of the potential risk to the fetus. Perform serial ultrasound examinations to assess the intra-amniotic environment. If oligohydramnios is observed, discontinue Lotrel, unless it is considered lifesaving for the mother. Fetal testing may be appropriate, based on the week of pregnancy. Patients and physicians should be aware, however, that oligohydramnios may not appear until after the fetus has sustained irreversible injury. Closely observe infants with histories of in utero exposure to Lotrel for hypotension, oliguria, and hyperkalemia.
Pregnancy Category (AUS):
- Australian Drug Evaluation Committee (ADEC) Pregnancy Category
There is no Australian Drug Evaluation Committee (ADEC) guidance on usage of Amlodipine and Benazepril in women who are pregnant.

### Labor and Delivery
- The effect of Lotrel on labor and delivery has not been studied.

### Nursing Mothers
- Minimal amounts of unchanged benazepril and of benazeprilat are excreted into the breast milk of lactating women treated with benazepril, so that a newborn child ingesting nothing but breast milk would receive less than 0.1% of the maternal doses of benazepril and benazeprilat.
- It is not known whether amlodipine is excreted in human milk. Nursing or drug should be discontinued.

### Pediatric Use
- Neonates with a history of in utero exposure to Lotrel:
- If oliguria or hypotension occurs, direct attention toward support of blood pressure and renal perfusion. Exchange transfusions or dialysis may be required as a means of reversing hypotension and/or substituting for disordered renal function. Benazepril, which crosses the placenta, can theoretically be removed from the neonatal circulation by these means; there are occasional reports of benefit from these maneuvers, but experience is limited.

### Geriatic Use
- In geriatrics, exposure to amlodipine is increased, thus consider lower initial doses of Lotrel.
- Of the total number of patients who received Lotrel in U.S. clinical studies of Lotrel, over 19% were 65 or older while about 2% were 75 or older. Overall differences in effectiveness or safety were not observed between these patients and younger patients. Clinical experience has not identified differences in responses between the elderly and younger patients, but greater sensitivity of some older individuals cannot be ruled out.

### Gender
There is no FDA guidance on the use of Amlodipine and Benazepril with respect to specific gender populations.

### Race
There is no FDA guidance on the use of Amlodipine and Benazepril with respect to specific racial populations.

### Renal Impairment
- In patients with severe renal impairment systemic exposure to benazepril is increased. The recommended dose of benazepril in this subgroup is 5 mg which is not an available strength with Lotrel. Lotrel is not recommended in patients with severe renal impairment. No dose adjustment of Lotrel is needed in patients with mild or moderate impairment of renal function.

### Hepatic Impairment
- Exposure to amlodipine is increased in patients with hepatic insufficiency, thus consider using lower doses of Lotrel.

### Females of Reproductive Potential and Males
There is no FDA guidance on the use of Amlodipine and Benazepril in women of reproductive potentials and males.

### Immunocompromised Patients
There is no FDA guidance one the use of Amlodipine and Benazepril in patients who are immunocompromised.

# Administration and Monitoring

### Administration
- Oral

### Monitoring
There is limited information regarding Monitoring of Amlodipine and Benazepril in the drug label.

# IV Compatibility
There is limited information regarding IV Compatibility of Amlodipine and Benazepril in the drug label.

# Overdosage

## Acute Overdose

### Signs and Symptoms
- Only a few cases of human overdose with amlodipine have been reported. One patient was asymptomatic after a 250-mg ingestion; another, who combined 70 mg of amlodipine with an unknown large quantity of a benzodiazepine, developed refractory shock and died.
- Human overdoses with any combination of amlodipine and benazepril have not been reported. In scattered reports of human overdoses with benazepril and other ACE inhibitors, there are no reports of death.
- Other clinical manifestations of overdose should be managed symptomatically based on modern methods of intensive care.
- To obtain up-to-date information about the treatment of overdose, a good resource is your certified Regional Poison-Control Center. Telephone numbers of certified poison-control centers are listed in the Physicians Desk Reference (PDR). In managing overdose, consider the possibilities of multiple-drug overdoses, drug-drug interactions, and unusual drug kinetics in your patient.
- The most likely effect of overdose with Lotrel is vasodilation, with consequent hypotension and tachycardia. Simple repletion of central fluid volume (Trendelenburg positioning, infusion of crystalloids) may be sufficient therapy, but pressor agents (norepinephrine or high-dose dopamine) may be required. With abrupt return of peripheral vascular tone, overdoses of other dihydropyridine calcium channel blockers have sometimes progressed to pulmonary edema, and patients must be monitored for this complication.
- Analyses of bodily fluids for concentrations of amlodipine, benazepril, or their metabolites are not widely available. Such analyses are, in any event, not known to be of value in therapy or prognosis.

### Management
- Patients should be admitted to hospital and, generally, should be managed in an intensive care setting, with continuous monitoring of cardiac function, blood gases, and blood biochemistry. Emergency supportive measures such as artificial ventilation or cardiac pacing should be instituted if appropriate.
- In the event of a potentially life-threatening oral overdose, use induction of vomiting or gastric lavage and/or activated charcoal to remove the drug from the gastrointestinal tract (only if presented within 1 hour after ingestion of Lotrel).
- Angiotensin II could presumably serve as a specific antagonist-antidote to benazepril, but angiotensin II is essentially unavailable outside of scattered research laboratories.
- No data are available to suggest physiologic maneuvers (e.g., maneuvers to change the pH of the urine) that might accelerate elimination of amlodipine, benazepril, or their metabolites. Benazeprilat is only slightly dialyzable; attempted clearance of amlodipine by hemodialysis or hemo-perfusion has not been reported, but amlodipines high protein binding makes it unlikely that these interventions will be of value.

## Chronic Overdose
There is limited information regarding Chronic Overdose of Amlodipine and Benazepril in the drug label.

# Pharmacology

## Mechanism of Action
- Benazepril and benazeprilat inhibit angiotensin-converting enzyme (ACE) in human subjects and in animals. ACE is a peptidyl dipeptidase that catalyzes the conversion of angiotensin I to the vasoconstrictor substance angiotensin II. Angiotensin II also stimulates aldosterone secretion by the adrenal cortex.
- Inhibition of ACE results in decreased plasma angiotensin II, which leads to decreased vasopressor activity and to decreased aldosterone secretion. The latter decrease may result in a small increase of serum potassium. Hypertensive patients treated with benazepril and amlodipine for up to 56 weeks had elevations of serum potassium up to 0.2 mEq/L.
- Removal of angiotensin II negative feedback on renin secretion leads to increased plasma renin activity. In animal studies, benazepril had no inhibitory effect on the vasopressor response to angiotensin II and did not interfere with the hemodynamic effects of the autonomic neurotransmitters acetylcholine, epinephrine, and norepinephrine.
- ACE is identical to kininase, an enzyme that degrades bradykinin. Whether increased levels of bradykinin, a potent vasodepressor peptide, play a role in the therapeutic effects of Lotrel remains to be elucidated.
- While the mechanism through which benazepril lowers blood pressure is believed to be primarily suppression of the renin-angiotensin aldosterone system, benazepril has an antihypertensive effect even in patients with low-renin hypertension.
- Amlodipine is a dihydropyridine calcium antagonist (calcium ion antagonist or slow channel blocker) that inhibits the transmembrane influx of calcium ions into vascular smooth muscle and cardiac muscle. Experimental data suggest that amlodipine binds to both dihydropyridine and nondihydropyridine binding sites. The contractile processes of cardiac muscle and vascular smooth muscle are dependent upon the movement of extracellular calcium ions into these cells through specific ion channels. Amlodipine inhibits calcium ion influx across cell membranes selectively, with a greater effect on vascular smooth muscle cells than on cardiac muscle cells. Negative inotropic effects can be detected in vitro but such effects have not been seen in intact animals at therapeutic doses. Serum calcium concentration is not affected by amlodipine. Within the physiologic pH range, amlodipine is an ionized compound (pKa=8.6), and its kinetic interaction with the calcium channel receptor is characterized by a gradual rate of association and dissociation with the receptor binding site, resulting in a gradual onset of effect.
- Amlodipine is a peripheral arterial vasodilator that acts directly on vascular smooth muscle to cause a reduction in peripheral vascular resistance and reduction in blood pressure.

## Structure
- Lotrel is a combination of amlodipine besylate and benazepril hydrochloride.
- Benazepril hydrochloride is a white to off-white crystalline powder, soluble (>100 mg/mL) in water, in ethanol, and in methanol. Benazepril hydrochlorides chemical name is 3-amino]-2,3,4,5-tetrahydro-2-oxo-1H-1-(3S)-benzazepine-1-acetic acid monohydrochloride; its structural formula is
- Its empirical formula is C24H28N2O5HCl, and its molecular weight is 460.96.
- Benazeprilat, the active metabolite of benazepril, is a nonsulfhydryl angiotensin-converting enzyme (ACE) inhibitor. Benazepril is converted to benazeprilat by hepatic cleavage of the ester group.
- Amlodipine besylate is a white to pale yellow crystalline powder, slightly soluble in water and sparingly soluble in ethanol. Its chemical name is (R,S)3-ethyl-5-methyl-2-(2-aminoethoxymethyl)-4-(2-chlorophenyl)-1,4-dihydro-6-methyl-3,5-pyridinedicarboxylate benzenesulfonate; its structural formula is
- Its empirical formula is C20H25ClN2O5C6H6O3S, and its molecular weight is 567.1.
- Amlodipine besylate is the besylate salt of amlodipine, a dihydropyridine calcium channel blocker.
- Lotrel capsules are formulated in six different strengths for oral administration with a combination of amlodipine besylate equivalent to 2.5 mg, 5 mg or 10 mg of amlodipine, with 10 mg, 20 mg or 40 mg of benazepril hydrochloride providing for the following available combinations: 2.5/10 mg, 5/10 mg, 5/20 mg, 5/40 mg, 10/20 mg and 10/40 mg.
- The inactive ingredients of the capsules are calcium phosphate, cellulose compounds, colloidal silicon dioxide, crospovidone, gelatin, hydrogenated castor oil (not present in 5/40 mg or 10/40 mg strengths), iron oxides, lactose, magnesium stearate, polysorbate 80, silicon dioxide, sodium lauryl sulfate, sodium starch (potato) glycolate, starch (corn), talc, and titanium dioxide.

## Pharmacodynamics
- Single and multiple doses of 10 mg or more of benazepril cause inhibition of plasma ACE activity by at least 80%-90% for at least 24 hours after dosing. For up to 4 hours after a 10-mg dose, pressor responses to exogenous angiotensin I were inhibited by 60%-90%.
- Administration of benazepril to patients with mild-to-moderate hypertension results in a reduction of both supine and standing blood pressure to about the same extent, with no compensatory tachycardia. Symptomatic postural hypotension is infrequent, although it can occur in patients who are salt and/or volume depleted.
- The antihypertensive effects of benazepril were not appreciably different in patients receiving high- or low-sodium diets.
- In normal human volunteers, single doses of benazepril caused an increase in renal blood flow but had no effect on glomerular filtration rate.
- Following administration of therapeutic doses to patients with hypertension, amlodipine produces vasodilation resulting in a reduction of supine and standing blood pressures. These decreases in blood pressure are not accompanied by a significant change in heart rate or plasma catecholamine levels with chronic dosing.
- With chronic once daily administration, antihypertensive effectiveness is maintained for at least 24 hours. Plasma concentrations correlate with effect in both young and elderly patients. The magnitude of reduction in blood pressure with amlodipine is also correlated with the height of pretreatment elevation; thus, individuals with moderate hypertension (diastolic pressure 105-114 mmHg) had about 50% greater response than patients with mild hypertension (diastolic pressure 90-104 mmHg). Normotensive subjects experienced no clinically significant change in blood pressure (+1/-2 mmHg).
- In hypertensive patients with normal renal function, therapeutic doses of amlodipine resulted in a decrease in renal vascular resistance and an increase in glomerular filtration rate and effective renal plasma flow without change in filtration fraction or proteinuria.
- As with other calcium channel blockers, hemodynamic measurements of cardiac function at rest and during exercise (or pacing) in patients with normal ventricular function treated with amlodipine have generally demonstrated a small increase in cardiac index without significant influence on dP/dt or on left ventricular end diastolic pressure or volume. In hemodynamic studies, amlodipine has not been associated with a negative inotropic effect when administered in the therapeutic dose range to intact animals and humans, even when coadministered with beta blockers to humans.
- Amlodipine does not change sinoatrial (SA) nodal function or atrioventricular (AV) conduction in intact animals or humans. In clinical studies in which amlodipine was administered in combination with beta blockers to patients with either hypertension or angina, no adverse effects on electrocardiographic parameters were observed.
- Amlodipine has demonstrated beneficial clinical effects in patients with chronic stable angina, vasospastic angina and angiographically documented coronary artery disease.

## Pharmacokinetics
- The rate and extent of absorption of benazepril and amlodipine from Lotrel are the same as when administered as individual tablets. Absorption from the individual tablets is not influenced by the presence of food in the gastrointestinal tract; food effects on absorption from Lotrel have not been studied.
- Absorption
- Following oral administration of Lotrel, peak plasma concentrations of amlodipine are reached in 612 hours. Absolute bioavailability has been calculated as between 64% and 90%. Following oral administration of Lotrel, the peak plasma concentrations of benazepril are reached in 0.5-2 hours. The cleavage of the ester group (primarily in the liver) converts benazepril to its active metabolite, benazeprilat, which reaches peak plasma concentrations in 1.5-4 hours. The extent of absorption of benazepril is at least 37%. Amlodipine and benazepril exhibit dose proportional pharmacokinetics between the therapeutic dose range of 2.5 and 10 mg and 10 and 20 mg, respectively.
- Distribution
- The apparent volume of distribution of amlodipine is about 21 L/kg. In vitro studies indicate that approximately 93% of circulating amlodipine is bound to plasma proteins in hypertensive patients. The apparent volume of distribution of benazeprilat is about 0.7 L/kg. Approximately 93% of circulating amlodipine is bound to plasma proteins, and the bound fraction of benazeprilat is slightly higher. On the basis of in vitro studies, benazeprilats degree of protein binding should be unaffected by age, by hepatic dysfunction, orover the therapeutic concentration rangeby concentration.
- Metabolism
- Amlodipine is extensively (approximately 90%) metabolized in the liver to inactive metabolites. Benazepril is extensively metabolized to form benazeprilat as the main metabolite, which occurs by enzymatic hydrolysis, mainly in the liver. Two minor metabolites are the acyl glucuronide conjugates of benazepril and benazeprilat.
- Elimination
- Amlodipine elimination from plasma is biphasic with a terminal elimination half-life of approximately 30 to 50 hours. Steady-state plasma levels are reached after once-daily dosing for 7 - 8 days. 10% of unchanged drug and 60% of amlodipine metabolites are excreted in urine. Effective elimination half-life of amlodipine is 2 days. Benazepril is eliminated mainly by metabolic clearance. Benazeprilat is eliminated via the kidneys and the bile; renal excretion is the main route in patients with normal renal function. In the urine, benazepril accounts for less than 1 % and benazeprilat for about 20 % of an oral dose. Elimination of benazeprilat is biphasic with an initial half-life of about 3 hours and a terminal half-life of about 22 hours. Benazeprilats effective elimination half-life is 10-11 hours, while that of amlodipine is about 2 days, so steady-state levels of the two components are achieved after about a week of once-daily dosing.
- Special populations
- Geriatric patients: No specific clinical studies were performed to understand the impact of age on the pharmacokinetics of amlodipine and benazepril as fixed dose combination. As individual component amlodipine is extensively metabolized in the liver. In the elderly, clearance of amlodipine is decreased with resulting increases in peak plasma levels, elimination half-life and area-under-the-plasma-concentration curve.
- Hepatic impairment: Patients with hepatic insufficiency have decreased clearance of amlodipine with a resulting increase in AUC of approximately 4060%. Pharmacokinetics of benazepril is not significantly influenced by hepatic impairment.
- Renal impairment: The disposition of benazepril and benazeprilat in patients with mild-to-moderate renal insufficiency (creatinine clearance > 30 mL/min) is similar to that in patients with normal renal function. In patients with creatinine clearance  30 mL/min, peak benazeprilat levels and the effective half-life increase, resulting in higher systemic exposures. Pharmacokinetics of amlodipine is not significantly influenced by renal impairment.
- Drug interactions
- In vitro data in human plasma indicate that amlodipine has no effect on the protein binding of digoxin, phenytoin, warfarin, and indomethacin.
- Cimetidine: Co-administration of amlodipine with cimetidine did not alter the pharmacokinetics of amlodipine.
- Grapefruit juice: Co-administration of 240 mL of grapefruit juice with a single oral dose of amlodipine 10 mg in 20 healthy volunteers had no significant effect on the pharmacokinetics of amlodipine.
- Maalox (antacid): Co-administration of the antacid Maalox with a single dose of amlodipine had no significant effect on the pharmacokinetics of amlodipine.
- Sildenafil: A single 100 mg dose of sildenafil in subjects with essential hypertension had no effect on the pharmacokinetic parameters of amlodipine. When amlodipine and sildenafil were used in combination, each agent independently exerted its own blood pressure lowering effect.
- Atorvastatin: Co-administration of multiple 10 mg doses of amlodipine with 80 mg of atorvastatin resulted in no significant change in the steady-state pharmacokinetic parameters of atorvastatin.
- Digoxin: Co-administration of amlodipine with digoxin did not change serum digoxin levels or digoxin renal clearance in normal volunteers.
- Ethanol (alcohol): Single and multiple 10 mg doses of amlodipine had no significant effect on the pharmacokinetics of ethanol.
- Warfarin: Co-administration of amlodipine with warfarin did not change the warfarin prothrombin response time.
- Simvastatin: Co-administration of multiple doses of 10 mg of amlodipine with 80 mg simvastatin resulted in a 77% increase in exposure to simvastatin compared to simvastatin alone.
- CYP3A inhibitors: Co-administration of a 180 mg daily dose of diltiazem with 5 mg amlodipine in elderly hypertensive patients resulted in a 60% increase in amlodipine systemic exposure. Erythromycin co-administration in healthy volunteers did not significantly change amlodipine systemic exposure. However, strong inhibitors of CYP3A4 (e.g., ketoconazole, itraconazole, ritonavir) may increase the plasma concentrations of amlodipine to a greater extent.
- The pharmacokinetic properties of benazepril are not affected by hydrochlorothiazide, furosemide, chlorthalidone, digoxin, propranolol, atenolol, nifedipine, amlodipine, naproxen, acetylsalicylic acid, or cimetidine. Likewise the administration of benazepril does not substantially affect the pharmacokinetics of these medications.

## Nonclinical Toxicology
- Carcinogenicity and mutagenicity studies have not been conducted with this combination. However, these studies have been conducted with amlodipine and benazepril alone (see below). No adverse effects on fertility occurred when the benazepril:amlodipine combination was given orally to rats of either sex at doses up to 15:7.5 mg (benazepril:amlodipine)/kg/day, prior to mating and throughout gestation.
- Benazepril
- No evidence of carcinogenicity was found when benazepril was administered to rats and mice for up to two years at doses of up to 150 mg/kg/day. When compared on the basis of body surface area, this dose is 18 and 9 times (rats and mice, respectively) the maximum recommended human dose (calculations assume a patient weight of 60 kg). No mutagenic activity was detected in the Ames test in bacteria, in an in vitro test for forward mutations in cultured mammalian cells, or in a nucleus anomaly test. At doses of 50-500 mg/kg/day (6-60 times the maximum recommended human dose on a body surface area basis), benazepril had no adverse effect on the reproductive performance of male and female rats.
- Amlodipine
- Rats and mice treated with amlodipine maleate in the diet for up to two years, at concentrations calculated to provide daily dosage levels of 0.5, 1.25, and 2.5 mg amlodipine/kg/day, showed no evidence of a carcinogenic effect of the drug. For the mouse, the highest dose was, on a body surface area basis, similar to the maximum recommended human dose  of 10 mg amlodipine/day. For the rat, the highest dose was, on a body surface area basis, about two and a half times the MRHD. (Calculations based on a 60 kg patient.)  Mutagenicity studies conducted with amlodipine maleate revealed no drug-related effects at either the gene or chromosome level.   There was no effect on the fertility of rats treated orally with amlodipine maleate (males for 64 days and females for 14 days prior to mating) at doses of up to 10 mg amlodipine/kg/day (about 10 times the MRHD of 10 mg/day on a body surface area basis).
- When rats received benazepril:amlodipine at doses ranging from 5:2.5 to 50:25 mg/kg/day, dystocia was observed at an increasing dose-related incidence at all doses tested. On a body surface area basis, the 2.5 mg/kg/day dose of amlodipine is 3.6 times the amlodipine dose delivered when the maximum recommended dose of Lotrel is given to a 50-kg woman. Similarly, the 5 mg/kg/day dose of benazepril is approximately twice the benazepril dose delivered when the maximum recommended dose of Lotrel is given to a 50-kg woman.  No teratogenic effects were seen when benazepril and amlodipine were administered in combination to pregnant rats or rabbits. Rats received doses of up to 50:25 mg (benazepril:amlodipine)/kg/day (24 times the maximum recommended human dose on a body surface area basis, assuming a 50-kg woman). Rabbits received doses of up to 1.5:0.75 mg/kg/day (equivalent to the maximum recommended dose of Lotrel given to a 50-kg woman).
- Benazepril
- No teratogenic effects of benazepril were seen in studies of pregnant rats, mice, and rabbits. On a body surface area basis, the maximum doses used in these studies were 60 times (in rats), 9 times (in mice), and about equivalent to (in rabbits) the maximum recommended human dose (assuming a 50-kg woman).
- Amlodipine
- No evidence of teratogenicity or other embryo/fetal toxicity was found when pregnant rats and rabbits were treated orally with amlodipine maleate at doses of up to 10 mg amlodipine/kg/day (respectively, about 10 and 20 times the maximum recommended human dose  of 10 mg amlodipine on a body surface area basis) during their respective periods of major organogenesis. (Calculations based on a patient weight of 60 kg.) However, litter size was significantly decreased (by about 50%) and the number of intrauterine deaths was significantly increased (about 5-fold) for rats receiving amlodipine maleate at a dose equivalent to 10 mg amlodipine/kg/day for 14 days before mating and throughout mating and gestation. Amlodipine maleate has been shown to prolong both the gestation period and the duration of labor in rats at this dose. There are no adequate and well-controlled studies in pregnant women. Amlodipine should be used during pregnancy only if the potential benefit justifies the potential risk to the fetus.

# Clinical Studies
- Over 950 patients received Lotrel once daily in six double-blind, placebo-controlled studies. The antihypertensive effect of a single dose persisted for 24 hours, with peak reductions achieved 2-8 hours after dosing.
- Once-daily doses of benazepril/amlodipine using benazepril doses of 10-20 mg and amlodipine doses of 2.5-10 mg decreased seated pressure (systolic/diastolic) 24 hours after dosing by about 10-25/6-13 mmHg.
- In two studies in patients not adequately controlled on either benazepril 40 mg alone (n=329) or amlodipine 10 mg alone (n=812) once daily doses of Lotrel 10/40 mg further decreased seated blood pressure compared to the respective monotherapy alone.
- Combination therapy was effective in blacks and nonblacks. Both components contributed to the antihypertensive efficacy in nonblacks, but virtually all of the antihypertensive effect in blacks could be attributed to the amlodipine component. Among nonblack patients in placebo-controlled trials comparing Lotrel to the individual components, the blood pressure lowering effects of the combination were shown to be additive and in some cases synergistic.
- During chronic therapy with Lotrel, the maximum reduction in blood pressure with any given dose is generally achieved after 1-2 weeks. The antihypertensive effects of Lotrel have continued during therapy for at least 1 year. Abrupt withdrawal of Lotrel has not been associated with a rapid increase in blood pressure.

# How Supplied
- Lotrel is available as capsules containing amlodipine besylate equivalent to 2.5 mg, 5 mg or 10 mg of amlodipine, with 10 mg, 20 mg or 40 mg of benazepril hydrochloride providing for the following available combinations: 2.5/10 mg, 5/10 mg, 5/20 mg, 5/40 mg, 10/20 mg and 10/40 mg. All six strengths are packaged in bottles of 100 capsules.
- Capsules are imprinted with Lotrel and appropriate code.
- Storage
- Store at 25C (77F); excursions permitted to 15-30C (59-86F). Protect from moisture. Dispense in tight container (USP).

## Storage
There is limited information regarding Amlodipine and Benazepril Storage in the drug label.

# Images

## Drug Images

## Package and Label Display Panel

# Patient Counseling Information
- Female patients of childbearing age should be told about the consequences of exposure to Lotrel during pregnancy. Discuss treatment options with women planning to become pregnant. Patients should be asked to report pregnancies to their physicians as soon as possible.

# Precautions with Alcohol
- Alcohol-Amlodipine and Benazepril interaction has not been established. Talk to your doctor about the effects of taking alcohol with this medication.

# Brand Names
- LOTREL

# Look-Alike Drug Names
There is limited information regarding Amlodipine and Benazepril Look-Alike Drug Names in the drug label.

# Drug Shortage Status

# Price