Diltiazem Hydrochloride

(Once-a-Day Dosage)

40-8791

Revised — June 2011

Rx Only

Diltiazem hydrochloride, USP is a calcium ion cellular influx inhibitor (slow channel blocker or calcium antagonist). Chemically, diltiazem hydrochloride is 1,5-benzothiazepin-4(5H)one,3-(acetyloxy)-5-[2-(dimethylamino)ethyl]-2,3-dihydro-2-(4-methoxyphenyl)-, monohydrochloride,(+)-cis-. The chemical structure is:

4789cec5-figure-01

Diltiazem hydrochloride, USP is a white to off-white crystalline powder with a bitter taste. It is soluble in water, methanol, and chloroform. It has a molecular weight of 450.98. Diltiazem hydrochloride, USP is formulated as a once-a-day extended release capsule containing either 120 mg, 180 mg, 240 mg, or 300 mg diltiazem hydrochloride.

Each diltiazem extended-release capsule, for oral administration, contains the following inactive ingredients:

120 mg — ammonio methacrylate copolymer NF, type A, ammonio methacrylate copolymer NF, type B, ammonium hydroxide, black iron oxide, gelatin, hydroxypropyl cellulose, pharmaceutical glaze, propylene glycol, silicon dioxide, simethicone, sodium lauryl sulfate, sugar spheres, talc, titanium dioxide, triethyl citrate

180 mg — ammonio methacrylate copolymer NF, type A, ammonio methacrylate copolymer NF, type B, ammonium hydroxide, D and C yellow #10, FD and C blue #1, FD and C green #3, gelatin, hydroxypropyl cellulose, pharmaceutical glaze, propylene glycol, silicon dioxide, simethicone, sodium lauryl sulfate, sugar spheres, talc, titanium dioxide, triethyl citrate

240 mg — ammonio methacrylate copolymer NF, type A, ammonio methacrylate copolymer NF, type B, ammonium hydroxide, D and C yellow #10, FD and C green #3, gelatin, hydroxypropyl cellulose, pharmaceutical glaze, propylene glycol, silicon dioxide, simethicone, sodium lauryl sulfate, sugar spheres, talc, titanium dioxide, triethyl citrate

300 mg— ammonio methacrylate copolymer NF, type A, ammonio methacrylate copolymer NF, type B, ammonium hydroxide, black iron oxide, D and C yellow #10, FD and C green #3, gelatin, hydroxypropyl cellulose, pharmaceutical glaze, propylene glycol, silicon dioxide, simethicone, sodium lauryl sulfate, sugar spheres, talc, titanium dioxide, triethyl citrate

This drug product conforms to USP Drug release test #11.

The therapeutic effects of diltiazem hydrochloride are believed to be related to its ability to inhibit the cellular influx of calcium ions during membrane depolarization of cardiac and vascular smooth muscle.

Diltiazem hydrochloride extended-release capsules, USP are indicated for the treatment of hypertension. It may be used alone or in combination with other antihypertensive medications.

Diltiazem hydrochloride extended-release capsules, USP are indicated for the management of chronic stable angina and angina due to coronary artery spasm.

Diltiazem hydrochloride is contraindicated in (1) patients with sick sinus syndrome except in the presence of a functioning ventricular pacemaker, (2) patients with second-or third-degree AV block except in the presence of a functioning ventricular pacemaker, (3) patients with hypotension (less than 90 mm Hg systolic), (4) patients who have demonstrated hypersensitivity to the drug, and (5) patients with acute myocardial infarction and pulmonary congestion documented by x-ray on admission.

1. Cardiac Conduction: Diltiazem prolongs AV node refractory periods without significantly prolonging sinus node recovery time, except in patients with sick sinus syndrome. This effect may rarely result in abnormally slow heart rates (particularly in patients with sick sinus syndrome) or second- or third-degree AV block (13 of 3290 patients or 0.40%). Concomitant use of diltiazem with beta-blockers or digitalis may result in additive effects on cardiac conduction. A patient with Prinzmetal’s angina developed periods of asystole (2 to 5 seconds) after a single dose of 60 mg of diltiazem (see ADVERSE REACTIONS).
   
2. Congestive Heart Failure: Although diltiazem has a negative inotropic effect in isolated animal tissue preparations, hemodynamic studies in humans with normal ventricular function have not shown a reduction in cardiac index nor consistent negative effects on contractility (dp/dt). An acute study of oral diltiazem in patients with impaired ventricular function (ejection fraction 24% ± 6%) showed improvement in indices of ventricular function without significant decrease in contractile function (dp/dt). Worsening of congestive heart failure has been reported in patients with preexisting impairment of ventricular function. Experience with the use of diltiazem hydrochloride in combination with beta-blockers in patients with impaired ventricular function is limited. Caution should be exercised when using this combination.
3. Hypotension: Decreases in blood pressure associated with diltiazem therapy may occasionally result in symptomatic hypotension.
4. Acute Hepatic Injury: Mild elevations of transaminases with and without concomitant elevation in alkaline phosphatase and bilirubin have been observed in clinical studies. Such elevations were usually transient and frequently resolved even with continued diltiazem treatment. In rare instances, significant elevations in enzymes such as alkaline phosphatase, LDH, SGOT, SGPT, and other phenomena consistent with acute hepatic injury have been noted. These reactions tended to occur early after therapy initiation (1 to 8 weeks) and have been reversible upon discontinuation of drug therapy. The relationship to diltiazem is uncertain in some cases, but probable in some (see PRECAUTIONS).

Serious adverse reactions have been rare in studies carried out to date, but it should be recognized that patients with impaired ventricular function and cardiac conduction abnormalities have usually been excluded from these studies.

The following table presents the most common adverse reactions reported in placebo-controlled angina and hypertension trials in patients receiving diltiazem hydrochloride extended-release capsules up to 360 mg with rates in placebo patients shown for comparison.

In clinical trials of diltiazem hydrochloride extended-release capsules, diltiazem hydrochloride tablets, and diltiazem hydrochloride sustained-release capsules involving over 3200 patients, the most common events (ie, greater than 1%) were edema (4.6%), headache (4.6%), dizziness (3.5%), asthenia (2.6%), first degree AV block (2.4%), bradycardia (1.7%), flushing (1.4%), nausea (1.4%), and rash (1.2%).

In addition, the following events were reported infrequently (less than 1%) in angina or hypertension trials:

Cardiovascular: Angina, arrhythmia, AV block (second- or third-degree), bundle branch block, congestive heart failure, ECG abnormalities, hypotension, palpitations, syncope, tachycardia, ventricular extrasystoles.

Nervous System: Abnormal dreams, amnesia, depression, gait abnormality, hallucinations, insomnia, nervousness, paresthesia, personality change, somnolence, tinnitus, tremor.

Gastrointestinal: Anorexia, constipation, diarrhea, dry mouth, dysgeusia, dyspepsia, mild elevations of SGOT, SGPT, LDH, and alkaline phosphatase (see WARNINGS, Acute Hepatic Injury), thirst, vomiting, weight increase

Dermatological: Petechiae, photosensitivity, pruritus, urticaria.

Other: Amblyopia, CPK increase, dyspnea, epistaxis, eye irritation, hyperglycemia, hyperuricemia, impotence, muscle cramps, nasal congestion, nocturia, osteoarticular pain, polyuria, sexual difficulties.

The following postmarketing events have been reported infrequently in patients receiving diltiazem hydrochloride: acute generalized exanthematous pustulosis, allergic reactions, alopecia, angioedema (including facial or periorbital edema), asystole, erythema multiforme (including Stevens-Johnson syndrome, toxic epidermal necrolysis), exfoliative dermatitis, extrapyramidal symptoms, gingival hyperplasia, hemolytic anemia, increased bleeding time, leukopenia, photosensitivity (including lichenoid keratosis and hyperpigmentation at sun-exposed skin areas), purpura, retinopathy, myopathy and thrombocytopenia. In addition, events such as myocardial infarction have been observed which are not readily distinguishable from the natural history of the disease in these patients. A number of well-documented cases of generalized rash, some characterized as leukocytoclastic vasculitis, have been reported. However, a definitive cause and effect relationship between these events and diltiazem therapy is yet to be established.

The oral LD50’s in mice and rats range from 415 to 740 mg/kg and from 560 to 810 mg/kg, respectively. The intravenous LD50’s in these species were 60 and 38 mg/kg, respectively. The oral LD50 in dogs is considered to be in excess of 50 mg/kg, while lethality was seen in monkeys at 360 mg/kg.

The toxic dose in man is not known. Due to extensive metabolism, blood levels after a standard dose of diltiazem can vary over tenfold, limiting the usefulness of blood levels in overdose cases.

There have been reports of diltiazem overdose in amounts ranging from less than 1 g to 18 g. Of cases with known outcome, most patients recovered and in cases with a fatal outcome, the majority involved multiple drug ingestion.

Events observed following diltiazem overdose included bradycardia, hypotension, heart block, and cardiac failure. Most reports of overdose described some supportive medical measure and/or drug treatment. Bradycardia frequently responded favorably to atropine, as did heart block, although cardiac pacing was also frequently utilized to treat heart block. Fluids and vasopressors were used to maintain blood pressure and in cases of cardiac failure, inotropic agents were administered. In addition, some patients received treatment with ventilatory support, gastric lavage, activated charcoal, and/or intravenous calcium.

The effectiveness of intravenous calcium administration to reverse the pharmacological effects of diltiazem overdose has been inconsistent. In a few reported cases, overdose with calcium channel blockers associated with hypotension and bradycardia that was initially refractory to atropine became more responsive to atropine after the patients received intravenous calcium. In some cases, intravenous calcium has been administered (1 g calcium chloride or 3 g calcium gluconate) over 5 minutes and repeated every 10 to 20 minutes as necessary. Calcium gluconate has also been administered as a continuous infusion at a rate of 2 g per hour for 10 hours. Infusions of calcium for 24 hours or more may be required. Patients should be monitored for signs of hypercalcemia.

In the event of overdose or exaggerated response, appropriate supportive measures should be employed in addition to gastrointestinal decontamination. Diltiazem does not appear to be removed by peritoneal or hemodialysis. Limited data suggest that plasmapheresis or charcoal hemoperfusion may hasten diltiazem elimination following overdose. Based on the known pharmacological effects of diltiazem and/or reported clinical experiences, the following measures may be considered:

Bradycardia : Administer atropine (0.60 to 1.0 mg). If there is no response to vagal blockade, administer isoproterenol cautiously.

High-degree AV Block: Treat as for bradycardia above. Fixed high-degree AV block should be treated with cardiac pacing.

Cardiac Failure: Administer inotropic agents (isoproterenol, dopamine, or dobutamine) and diuretics.

Hypotension: Vasopressors (e.g., dopamine or norepinephrine).

Actual treatment and dosage should depend on the severity of the clinical situation and the judgment and experience of the treating physician.

Patients controlled on diltiazem alone or in combination with other medications may be switched to diltiazem hydrochloride extended-release capsules at the nearest equivalent total daily dose. Higher doses of diltiazem hydrochloride extended-release capsules may be needed in some patients. Patients should be closely monitored. Subsequent titration to higher or lower doses may be necessary and should be initiated as clinically warranted. There is limited general clinical experience with doses above 360 mg, but doses to 540 mg have been studied in clinical trials. The incidence of side effects increases as the dose increases with first-degree AV block, dizziness, and sinus bradycardia bearing the strongest relationship to dose.

Hypertension: Dosage needs to be adjusted by titration to individual patient needs. When used as monotherapy, reasonable starting doses are 180 to 240 mg once daily, although some patients may respond to lower doses. Maximum antihypertensive effect is usually observed by 14 days of chronic therapy; therefore, dosage adjustments should be scheduled accordingly. The usual dosage range studied in clinical trials was 240 to 360 mg once daily. Individual patients may respond to higher doses of up to 480 mg once daily.

Angina: Dosages for the treatment of angina should be adjusted to each patient’s needs, starting with a dose of 120 or 180 mg once daily. Individual patients may respond to higher doses of up to 480 mg once daily. When necessary, titration may be carried out over a 7- to 14-day period.

Concomitant Use  With Other Cardiovascular Agents

1. Sublingual NTG - May be taken as required to abort acute anginal attacks during diltiazem hydrochloride extended-release capsules therapy.
   
2. Prophylactic Nitrate Therapy - Diltiazem hydrochloride extended-release capsules may be safely coadministered with short-and long-acting nitrates.
   
3. Beta-Blockers - (See WARNINGS and PRECAUTIONS).
   
4. Antihypertensives - Diltiazem hydrochloride extended-release capsules have an additive antihypertensive effect when used with other antihypertensive agents. Therefore, the dosage of diltiazem hydrochloride extended-release capsules or the concomitant antihypertensives may need to be adjusted when adding one to the other.

Diltiazem Hydrochloride Extended-release Capsules, USP are supplied as follows:

120 mg — Each #2 capsule with light gray opaque cap and body printed with 4789cec5-figure-02 and 2588 on both cap and body in white ink contains 120 mg of diltiazem hydrochloride, USP. Capsules are supplied in bottles of 30 (NDC 0228-2588-03), 90 (NDC 0228-2588-09) and 500 (NDC 0228-2588-50).

180 mg — Each #0 capsule with dark green opaque cap and aqua blue opaque body printed with 4789cec5-figure-03 and 2577 on both cap and body in white ink contains 180 mg of diltiazem hydrochloride, USP. Capsules are supplied in bottles of 30 (NDC 0228-2577-03), 90 (NDC 0228-2577-09) and 500 (NDC 0228-2577-50).

240 mg — Each #0EL capsule with dark green opaque cap and body printed with 4789cec5-figure-04 and 2578 on both cap and body in white ink contains 240 mg of diltiazem hydrochloride, USP. Capsules are supplied in bottles of 30 (NDC 0228-2578-03), 90 (NDC 0228-2578-09) and 500 (NDC 0228-2578-50).

300 mg — Each #00 capsule with dark green opaque cap and light gray opaque body printed with 4789cec5-figure-05 and 2579 on both cap and body in white ink contains 300 mg of diltiazem hydrochloride, USP. Capsules are supplied in bottles of 30 (NDC 0228-2579-03), 90 (NDC 0228-2579-09) and 500 (NDC 0228-2579-50).

Dispense in tight, light-resistant containers as defined in the USP.

Store at 25°C (77°F); excursions permitted to 15° to 30°C (59° to 86°F).

Avoid excessive humidity.

Manufactured by:

Actavis Elizabeth LLC

200 Elmora Avenue

Elizabeth, NJ 07207 USA

40-8791

Revised — June 2011

NDC 66336-0669-XX

NDC 66336-0669-XX
NDC 66336-0669-90