VERAPAMIL HYDROCHLORIDE
Extended-release Capsules
120 mg, 180 mg and 240 mg

Verapamil hydrochloride extended-release is a calcium ion influx inhibitor (slow channel blocker or calcium ion antagonist). Verapamil hydrochloride extended-release is available for oral administration as a 120 mg hard gelatin capsule, a 180 mg hard gelatin capsule and a 240 mg hard gelatin capsule. These bead filled capsules provide an extended-release of the drug in the gastrointestinal tract. The structural formula of verapamil hydrochloride is given below:

C₂₇H₃₈N₂O₄• HCl

M.W. 491.07

Chemical name: (±)-5-[(3,4-Dimethoxyphenethyl) methylamino]-2-(3,4-dimethoxyphenyl)-2-isopropylvaleronitrile monohydrochloride.

Verapamil hydrochloride is an almost white, crystalline powder, practically free of odor, with a bitter taste. It is soluble in water, chloroform and methanol. Verapamil hydrochloride is not structurally related to other cardioactive drugs.

In addition to verapamil hydrochloride, verapamil hydrochloride extended-release capsules contain the following inactive ingredients: ammonium hydroxide, colloidal silicon dioxide, D&C yellow no. 10 aluminum lake, dibutyl sebacate, diethyl phthalate, ethylcellulose, FD&C blue no. 2 aluminum lake, FD&C blue no. 1 aluminum lake, FD&C green #3, FD&C red no. 40 aluminum lake, gelatin, hypromellose, isopropyl alcohol, maltodextrin, methacrylic acid copolymer, n-butyl alcohol, oleic acid, pharmaceutical glaze, polyethylene glycol, povidone, propylene glycol, SDA-3A alcohol, silicon dioxide, sodium lauryl sulfate, sugar spheres, synthetic black iron oxide, talc, and titanium dioxide. In addition the 180 mg capsule contains D&C yellow #10.

Verapamil hydrochloride extended-release is a calcium ion influx inhibitor (slow channel blocker or calcium ion antagonist) which exerts its pharmacologic effects by modulating the influx of ionic calcium across the cell membrane of the arterial smooth muscle as well as in conductile and contractile myocardial cells.

Normal sinus rhythm is usually not affected by verapamil hydrochloride. However in patients with sick sinus syndrome, verapamil hydrochloride may interfere with sinus node impulse generation and may induce sinus arrest or sinoatrial block. Atrioventricular block can occur in patients without preexisting conduction defects. (See WARNINGS.) Verapamil hydrochloride does not alter the normal atrial action potential or intraventricular conduction time, but depresses amplitude, velocity of depolarization and conduction in depressed atrial fibers. Verapamil hydrochloride may shorten the antegrade effective refractory period of accessory bypass tracts. Acceleration of ventricular rate and/or ventricular fibrillation has been reported in patients with atrial flutter or atrial fibrillation and a coexisting accessory AV pathway following administration of verapamil. (See WARNINGS.)

Verapamil hydrochloride has a local anesthetic action that is 1.6 times that of procaine on an equimolar basis. It is not known whether this action is important at the doses used in man.

With the immediate-release formulations, more than 90% of the orally administered dose is absorbed, and peak plasma concentrations of verapamil are observed 1 to 2 hours after dosing. Because of rapid biotransformation of verapamil during its first pass through the portal circulation, the absolute bioavailability ranges from 20% to 35%. Chronic oral administration of the highest recommended dose (120 mg every 6 hours) resulted in plasma verapamil levels ranging from 125 to 400 ng/mL with higher values reported occasionally. A nonlinear correlation between the verapamil hydrochloride dose administered and verapamil plasma levels does exist.

During initial dose titration with verapamil a relationship exists between verapamil plasma concentrations and the prolongation of the PR interval. However, during chronic administration this relationship may disappear. The quantitative relationship between plasma verapamil concentrations and blood pressure reduction has not been fully characterized.

In a multiple dose pharmacokinetic study, peak concentrations for a single daily dose of verapamil hydrochloride extended-release 240 mg were approximately 65% of those obtained with an 80 mg t.i.d. dose of the conventional immediate-release tablets, and the 24-hour post-dose concentrations were approximately 30% higher. At a total daily dose of 240 mg, verapamil hydrochloride extended-release was shown to have a similar extent of verapamil bioavailability based on the AUC-24 as that obtained with the conventional immediate-release tablets. In this same study verapamil hydrochloride extended-release doses of 120 mg, 240 mg and 360 mg once daily were compared after multiple doses. The ratios of the verapamil and norverapamil AUCs for verapamil hydrochloride extended-release 120 mg, 240 mg and 360 mg once daily doses are 1 (565 ng∙hr/mL):3 (1660 ng∙hr/mL):5 (2729 ng∙hr/mL) and 1 (621 ng∙hr/mL):3 (1614 ng∙hr/mL):4 (2535 ng∙hr/mL), respectively, indicating that the AUC increased non-proportionately with increasing doses.

Food does not affect the extent or rate of the absorption of verapamil from the verapamil hydrochloride extended-release capsule. The verapamil hydrochloride extended-release 240 mg capsule when administered with food had a C_max of 77 ng/mL which occurred 9.0 hours after dosing, and an AUC(0–inf) of 1387 ng∙hr/mL. Verapamil hydrochloride extended-release 240 mg under fasting conditions had a C_max of 77 ng/mL which occurred 9.8 hours after dosing, and an AUC(0–inf) of 1541 ng∙hr/mL.

The bioequivalence of verapamil hydrochloride extended-release 240 mg, administered as the beads sprinkled on applesauce and as the intact capsule, was demonstrated in a single-dose, cross-over study in 32 healthy adults. Comparative ratios (sprinkled/intact) of verapamil were 0.95, 1.02, and 1.01 for C_max, T_max, and AUC(0–inf) respectively. Similar results were observed with norverapamil.

The time to reach maximum verapamil concentrations (T_max) with verapamil hydrochloride extended-release has been found to be approximately 7 to 9 hours in each of the single dose (fasting), single dose (fed), the multiple dose (steady-state) studies, and dose proportionality pharmacokinetic studies. Similarly the apparent half-life (t_1/2) has been found to be approximately 12 hours independent of dose. Aging may affect the pharmacokinetics of verapamil. Elimination half-life may be prolonged in the elderly.

In healthy man, orally administered verapamil hydrochloride undergoes extensive metabolism in the liver. Twelve metabolites have been identified in plasma; all except norverapamil are present in trace amounts only. Norverapamil can reach steady-state plasma concentrations approximately equal to those of verapamil itself. The biologic activity of norverapamil appears to be approximately 20% that of verapamil.

Approximately 70% of an administered dose of verapamil hydrochloride is excreted as metabolites in the urine and 16% or more in the feces within 5 days. About 3% to 4% is excreted in the urine as unchanged drug. Approximately 90% is bound to plasma proteins. In patients with hepatic insufficiency, metabolism is delayed and elimination half-life prolonged up to 14 to 16 hours (see PRECAUTIONS), the volume of distribution is increased, and plasma clearance reduced to about 30% of normal. Verapamil clearance values suggest that patients with liver dysfunction may attain therapeutic verapamil plasma concentrations with one-third of the oral daily dose required for patients with normal liver function.

After four weeks of oral dosing (120 mg q.i.d.), verapamil and norverapamil levels were noted in the cerebrospinal fluid with estimated partition coefficient of 0.06 for verapamil and 0.04 for norverapamil.

In 10 healthy males, administration of oral verapamil (80 mg every 8 hours for 6 days) and a single oral dose of ethanol (0.8 g/kg), resulted in a 17% increase in mean peak ethanol concentrations (106.45 ± 21.40 to 124.23 ± 24.74 mg/dL) compared with placebo. (See PRECAUTIONS: Drug Interactions.)

The area under the blood ethanol concentration versus time curve (AUC over 12 hours) increased by 30% (365.67 ± 93.52 to 475.07 ± 97.24 mg∙hr/dL). Verapamil AUCs were positively correlated (r=0.71) to increased ethanol blood AUC values.

Verapamil hydrochloride reduces afterload and myocardial contractility. Improved left ventricular diastolic function in patients with IHSS and those with coronary heart disease has also been observed with verapamil hydrochloride therapy. In most patients, including those with organic cardiac disease, the negative inotropic action of verapamil hydrochloride is countered by reduction of afterload and cardiac index is usually not reduced. In patients with severe left ventricular dysfunction however, (e.g., pulmonary wedge pressure above 20 mm Hg or ejection fraction lower than 30%), or in patients on beta-adrenergic blocking agents or other cardiodepressant drugs, deterioration of ventricular function may occur. (See PRECAUTIONS: Drug Interactions.)

Verapamil hydrochloride does not induce bronchoconstriction and hence, does not impair ventilatory function.

Verapamil hydrochloride extended-release capsules are indicated for the management of essential hypertension.

Verapamil hydrochloride is contraindicated in:

• Severe left ventricular dysfunction. (See WARNINGS.)
• Hypotension (less than 90 mm Hg systolic pressure) or cardiogenic shock.
• Sick sinus syndrome (except in patients with a functioning artificial ventricular pacemaker).
• Second- or third-degree AV block (except in patients with a functioning artificial ventricular pacemaker).
• Patients with atrial flutter or atrial fibrillation and an accessory bypass tract (e.g., Wolff-Parkinson-White, Lown-Ganong-Levine syndromes). (See WARNINGS.)
• Patients with known hypersensitivity to verapamil hydrochloride.

Verapamil has a negative inotropic effect which, in most patients, is compensated by its afterload reduction (decreased systemic vascular resistance) properties without a net impairment of ventricular performance. In clinical experience with 4,954 patients, 87 (1.8%) developed congestive heart failure or pulmonary edema. Verapamil should be avoided in patients with severe left ventricular dysfunction (e.g., ejection fraction less than 30% or moderate to severe symptoms of cardiac failure) and in patients with any degree of ventricular dysfunction if they are receiving a beta-adrenergic blocker. (See PRECAUTIONS: Drug Interactions.) Patients with milder ventricular dysfunction should, if possible, be controlled with optimum doses of digitalis and/or diuretics before verapamil treatment (note interactions with digoxin under: PRECAUTIONS).

Occasionally, the pharmacologic action of verapamil may produce a decrease in blood pressure below normal levels which may result in dizziness or symptomatic hypotension. The incidence of hypotension observed in 4,954 patients enrolled in clinical trials was 2.5%. In hypertensive patients, decreases in blood pressure below normal are unusual. Tilt table testing (60 degrees) was not able to induce orthostatic hypotension.

Elevations of transaminases with and without concomitant elevations in alkaline phosphatase and bilirubin have been reported. Such elevations have sometimes been transient and may disappear even in the face of continued verapamil treatment. Several cases of hepatocellular injury related to verapamil have been proven by rechallenge; half of these had clinical symptoms (malaise, fever, and/or right upper quadrant pain) in addition to elevations of SGOT, SGPT, and alkaline phosphatase. Periodic monitoring of liver function in patients receiving verapamil is therefore prudent.

Some patients with paroxysmal and/or chronic atrial flutter or atrial fibrillation and a coexisting accessory AV pathway have developed increased antegrade conduction across the accessory pathway bypassing the AV node, producing a very rapid ventricular response or ventricular fibrillation after receiving intravenous verapamil (or digitalis). Although a risk of this occurring with oral verapamil has not been established, such patients receiving oral verapamil may be at risk and its use in these patients is contraindicated. (See CONTRAINDICATIONS.)

Treatment is usually DC-cardioversion. Cardioversion has been used safely and effectively after oral verapamil.

The effect of verapamil on AV conduction and the SA node may lead to asymptomatic first-degree AV block and transient bradycardia, sometimes accompanied by nodal escape rhythms. PR interval prolongation is correlated with verapamil plasma concentrations, especially during the early titration phase of therapy. Higher degrees of AV block, however, were infrequently (0.8%) observed.

Marked first-degree block or progressive development to second- or third-degree AV block requires a reduction in dosage or, in rare instances, discontinuation of verapamil hydrochloride and institution of appropriate therapy depending upon the clinical situation.

In 120 patients with hypertrophic cardiomyopathy (most of them refractory or intolerant to propranolol) who received therapy with verapamil at doses up to 720 mg/day, a variety of serious adverse effects were seen. Three patients died in pulmonary edema; all had severe left ventricular outflow obstruction and a past history of left ventricular dysfunction. Eight other patients had pulmonary edema and/or severe hypotension; abnormally high (over 20 mm Hg) capillary wedge pressure and a marked left ventricular outflow obstruction were present in most of these patients. Concomitant administration of quinidine (see PRECAUTIONS: Drug Interactions) preceded the severe hypotension in 3 of the 8 patients (2 of whom developed pulmonary edema). Sinus bradycardia occurred in 11% of the patients, second-degree AV block in 4% and sinus arrest in 2%. It must be appreciated that this group of patients had a serious disease with a high mortality rate. Most adverse effects responded well to dose reduction and only rarely did verapamil have to be discontinued.

THE CONTENTS OF THE VERAPAMIL HYDROCHLORIDE EXTENDED-RELEASE CAPSULE SHOULD NOT BE CRUSHED OR CHEWED.

When the sprinkle method of administration is prescribed, details of the proper technique should be explained to the patient. (See DOSAGE AND ADMINISTRATION.)

An 18-month toxicity study in rats, at a low multiple (6-fold) of the maximum recommended human dose, and not the maximum tolerated dose, did not suggest a tumorigenic potential. There was no evidence of a carcinogenic potential of verapamil administered in the diet of rats for two years at doses of 10, 35, and 120 mg/kg per day or approximately 1x, 3.5x, and 12x, respectively, the maximum recommended human daily dose (480 mg per day or 9.6 mg/kg/day).

Verapamil was not mutagenic in the Ames test in 5 test strains at 3 mg per plate, with or without metabolic activation.

Studies in female rats at daily dietary doses up to 5.5 times (55 mg/kg/day) the maximum recommended human dose did not show impaired fertility. Effects on male fertility have not been determined.

It is not known whether the use of verapamil during labor or delivery has immediate or delayed adverse effects on the fetus, or whether it prolongs the duration of labor or increases the need for forceps delivery or other obstetric intervention. Such adverse experiences have not been reported in the literature, despite a long history of use of verapamil hydrochloride in Europe in the treatment of cardiac side effects of beta-adrenergic agonist agents used to treat premature labor.

Verapamil is excreted in human milk. Because of the potential for adverse reactions in nursing infants from verapamil, nursing should be discontinued while verapamil is administered.

Safety and efficacy of verapamil in pediatric patients below the age of 18 years have not been established.

Clinical studies of verapamil did not include sufficient number of subjects aged 65 and over to determine whether they respond differently from younger subjects. Other reported clinical experience has not identified differences in responses between the elderly and younger patients. In general, dose selection for an elderly patient should be cautious, usually starting at the low end of the dosing range, reflecting the greater frequency of decreased hepatic, renal, or cardiac function, and of concomitant disease or other drug therapy.

Aging may affect the pharmacokinetics of verapamil. Elimination half-life may be prolonged in the elderly (see CLINICAL PHARMACOLOGY: Pharmacokinetics and Metabolism).

Verapamil is highly metabolized by the liver, and about 70% of the administered dose is excreted as metabolites in the urine. Clinical circumstances, some of which may be more common in the elderly, such as hepatic or renal impairment, should be considered (see PRECAUTIONS: General). In general, lower initial doses of verapamil hydrochloride extended-release capsules may be warranted in the elderly (see DOSAGE AND ADMINISTRATION).

In chronic animal toxicology studies verapamil causes lenticular and/or suture line changes at 30 mg/kg/day or greater and frank cataracts at 62.5 mg/kg/day or greater in the beagle dog but not the rat. Development of cataracts due to verapamil has not been reported in man.

Serious adverse reactions are uncommon when verapamil hydrochloride therapy is initiated with upward dose titration within the recommended single and total daily dose. See WARNINGS for discussion of heart failure, hypotension, elevated liver enzymes, AV block, and rapid ventricular response. Reversible (upon discontinuation of verapamil) non-obstructive, paralytic ileus has been infrequently reported in association with the use of verapamil.

In clinical trials involving 285 hypertensive patients on verapamil hydrochloride extended-release for greater than 1 week the following adverse reactions were reported in greater than 1% of the patients:

In clinical trials of other formulations of verapamil hydrochloride (N=4,954) the following reactions have occurred at rates greater than 1%:

In clinical trials related to the control of ventricular response in digitalized patients who had atrial fibrillation or atrial flutter, ventricular rate below 50/min at rest occurred in 15% of patients and asymptomatic hypotension occurred in 5% of patients.

The following reactions, reported in 1% or less of patients, occurred under conditions (open trials, marketing experience) where a causal relationship is uncertain; they are uled to alert the physician to a possible relationship:

Cardiovascular: angina pectoris, atrioventricular dissociation, chest pain, claudication, myocardial infarction, palpitations, purpura (vasculitis), syncope.

Digestive System: diarrhea, dry mouth, gastrointestinal distress, gingival hyperplasia.

Hemic and Lymphatic: ecchymosis or bruising.

Nervous System: cerebrovascular accident, confusion, equilibrium disorders, insomnia, muscle cramps, paresthesia, psychotic symptoms, shakiness, somnolence.

Respiratory: dyspnea.

Skin: arthralgia and rash, exanthema, hair loss, hyperkeratosis, maculae, sweating, urticaria, Stevens-Johnson syndrome, erythema multiforme.

Special Senses: blurred vision, tinnitus.

Urogenital: gynecomastia, impotence, increased urination, spotty menstruation.

The frequency of cardiovascular adverse reactions which require therapy is rare; hence, experience with their treatment is limited. Whenever severe hypotension or complete AV block occurs following oral administration of verapamil, the appropriate emergency measures should be applied immediately, e.g., intravenously administered isoproterenol hydrochloride, norepinephrine, atropine (all in the usual doses), or calcium gluconate (10% solution). In patients with hypertrophic cardiomyopathy (IHSS), alpha-adrenergic agents (phenylephrine, metaraminol bitartrate or methoxamine) should be used to maintain blood pressure, and isoproterenol and levarterenol should be avoided. If further support is necessary, inotropic agents (dopamine or dobutamine) may be administered. Actual treatment and dosage should depend on the severity and the clinical situation and the judgment and experience of the treating physician.

There is no specific antidote for verapamil overdosage; treatment should be supportive. Delayed pharmacodynamic consequences may occur with extended-release formulations, and patients should be observed for at least 48 hours, preferably under continuous hospital care. Reported effects include hypotension, bradycardia, cardiac conduction defects, arrhythmias, hyperglycemia, and decreased mental status. In addition, there have been literature reports of noncardiogenic pulmonary edema in patients taking large overdoses of verapamil (up to approximately 9 g).

In acute overdosage, gastrointestinal decontamination with cathartics and whole bowel irrigation should be considered. Calcium, inotropes (i.e., isoproterenol, dopamine, and glucagon), atropine, vasopressors (i.e., norepinephrine, and epinephrine), and cardiac pacing have been used with variable results to reverse hypotension and myocardial depression. In a few reported cases, overdose with calcium channel blockers that was initially refractory to atropine became more responsive to this treatment when the patients received large doses (close to 1 gram/hour for more than 24 hours) of calcium chloride. Calcium chloride is preferred to calcium gluconate since it provides 3 times more calcium per volume. Asystole should be handled by the usual measures including cardiopulmonary resuscitation. Verapamil cannot be removed by hemodialysis.

The dose of verapamil hydrochloride extended-release should be individualized by titration. The usual daily dose of extended-release verapamil hydrochloride in clinical trials has been 240 mg given by mouth once daily in the morning. However, initial doses of 120 mg a day may be warranted in patients who may have an increased response to verapamil (e.g., elderly, small people, etc.). Upward titration should be based on therapeutic efficacy and safety evaluated approximately 24 hours after dosing. The antihypertensive effects of verapamil hydrochloride extended-release are evident within the first week of therapy.

If adequate response is not obtained with 120 mg of verapamil hydrochloride extended-release, the dose may be titrated upward in the following manner:

• (a)180 mg in the morning,
• (b)240 mg in the morning,
• (c)360 mg in the morning,
• (d)480 mg in the morning.

Verapamil extended-release capsules are for once-a-day administration. When switching from immediate-release verapamil to verapamil hydrochloride extended-release capsules, the same total daily dose of verapamil hydrochloride extended-release capsules can be used.

As with immediate-release verapamil, dosages of verapamil hydrochloride extended-release capsules should be individualized and titration may be needed in some patients.

Verapamil Hydrochloride Extended-release Bead Filled Capsules may also be administered by carefully opening the capsule and sprinkling the beads on a spoonful of applesauce. The applesauce should be swallowed immediately without chewing and followed with a glass of cool water to ensure complete swallowing of the beads. The applesauce used should not be hot, and it should be soft enough to be swallowed without chewing. Any bead/applesauce mixture should be used immediately and not stored for future use. Subdividing the spans of a verapamil hydrochloride extended-release capsule is not recommended.

Verapamil Hydrochloride Extended-release Capsules, are available in 120 mg, 180 mg and 240 mg capsules.

The 120 mg capsules have a bluish green opaque cap and white opaque body that are radially printed with MYLAN over 6320 in black ink. They are available as follows:

NDC 0378-6320-01
bottles of 100 capsules
NDC 0378-6320-05
bottles of 500 capsules

The 180 mg capsules have a bluish green opaque cap and light green opaque body that are radially printed with MYLAN over 6380 in black ink. They are available as follows:

NDC 0378-6380-01
bottles of 100 capsules
NDC 0378-6380-05
bottles of 500 capsules

The 240 mg capsule is an elongated capsule with a bluish green opaque cap and bluish green opaque body that are radially printed with MYLAN over 6440 in black ink. They are available as follows:

NDC 0378-6440-01
bottles of 100 capsules
NDC 0378-6440-05
bottles of 500 capsules