DILTIAZEM HYDROCHLORIDE

Diltiazem hydrochloride is a nondihydropyridine calcium channel blocker (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 structural formula is: Diltiazem hydrochloride is a white, odorless, crystalline powder or small crystals. It is freely soluble in chloroform, in formic acid, in methanol, and in water, sparingly soluble in dehydrated alcohol, insoluble in ether. It has a molecular weight of 450.99. Diltiazem hydrochloride extended-release tablets are formulated as a once-a-day extended-release tablet for oral administration containing 120 mg, 180 mg, 240 mg, 300 mg, 360 mg or 420 mg of diltiazem hydrochloride. Tablets also contain: colloidal silicon dioxide, ethyl cellulose, hypromellose, isopropyl alcohol, magnesium stearate, microcrystalline cellulose, polyethylene glycol, povidone, titanium dioxide and triethyl citrate. structure.jpg

Diltiazem Hydrochloride Extended-Release Tablet is a nondihydropyridine calcium channel blocker indicated for: treatment of hypertension, to lower blood pressure. Lowering blood pressure reduces the risk of fatal and nonfatal cardiovascular events, primarily strokes and myocardial infarctions. It can be used alone or in combination with other antihypertensives. ( 1.1 ) improving exercise tolerance in patients with chronic stable angina. ( 1.2 ) 1.1 Hypertension Diltiazem Hydrochloride Extended-Release Tablets are indicated for the treatment of hypertension, to lower blood pressure. Lowering blood pressure reduces the risk of fatal and nonfatal cardiovascular events, primarily strokes and myocardial infarctions. These benefits have been seen in controlled trials of antihypertensive drugs from a wide variety of pharmacologic classes including this drug. Control of high blood pressure should be part of comprehensive cardiovascular risk management, including, as appropriate, lipid control, diabetes management, antithrombotic therapy, smoking cessation, exercise, and limited sodium intake. Many patients will require more than one drug to achieve blood pressure goals. For specific advice on goals and management, see published guidelines, such as those of the National High Blood Pressure Education Program’s Joint National Committee on Prevention, Detection, Evaluation, and Treatment of High Blood Pressure (JNC). Numerous antihypertensive drugs, from a variety of pharmacologic classes and with different mechanisms of action, have been shown in randomized controlled trials to reduce cardiovascular morbidity and mortality, and it can be concluded that it is blood pressure reduction, and not some other pharmacologic property of the drugs, that is largely responsible for those benefits. The largest and most consistent cardiovascular outcome benefit has been a reduction in the risk of stroke, but reductions in myocardial infarction and cardiovascular mortality also have been seen regularly. Elevated systolic or diastolic pressure causes increased cardiovascular risk, and the absolute risk increase per mm Hg is greater at higher blood pressures, so that even modest reductions of severe hypertension can provide substantial benefit. Relative risk reduction from blood pressure reduction is similar across populations with varying absolute risk, so the absolute benefit is greater in patients who are at higher risk independent of their hypertension (for example, patients with diabetes or hyperlipidemia), and such patients would be expected to benefit from more aggressive treatment to a lower blood pressure goal. Some antihypertensive drugs have smaller blood pressure effects (as monotherapy) in black patients, and many antihypertensive drugs have additional approved indications and effects (e.g., on angina, heart failure, or diabetic kidney disease). These considerations may guide selection of therapy. Diltiazem hydrochloride extended-release tablets may be used alone or in combination with other antihypertensive medications. 1.2 Angina Diltiazem hydrochloride extended-release tablets are indicated to improve exercise tolerance in patients with chronic stable angina.

Take diltiazem hydrochloride extended-release tablets once a day at approximately the same time. Do not chew or crush the tablet. Tablet should be swallowed whole and not chewed or crushed. ( 2 ) Hypertension: Initial adult dose is 180 to 240 mg once daily. Adjust dose according to blood pressure response to a maximum of 540 mg daily ( 2.1 ) Angina: Initial adult dose is 180 mg once daily. Adjust dose according to response to a maximum of 360 mg. ( 2.2 ) Switching to Diltiazem Hydrochloride Extended-Release Tablets: Patients may be switched to the nearest equivalent total daily diltiazem dose. ( 2.3 ) 2.1 Hypertension Initiate dosing at 180mg to 240 mg once daily, although some patients may respond to lower doses. Titrate according to blood pressure to a maximum of 540 mg daily. Maximum antihypertensive effect is usually observed by 14 days of chronic therapy. 2.2 Angina Initiate dosing at 180 mg once daily and increase dose at intervals of 7 to 14 days if adequate response is not obtained, to a maximum of 360 mg. 2.3 Switching to diltiazem hydrochloride extended-release tablets Patients controlled on diltiazem alone or in combination with other medications may be switched to diltiazem hydrochloride extended-release tablets once a day at the nearest equivalent total daily dose. Higher doses of diltiazem hydrochloride extended-release tablets may be needed in some patients based on clinical response.

Diltiazem hydrochloride extended-release tablets are contraindicated in: Patients with sick sinus syndrome except in the presence of a functioning ventricular pacemaker. Patients with second- or third-degree AV block except in the presence of a functioning ventricular pacemaker. Patients with hypotension (less than 90 mm Hg systolic). Patients who have demonstrated hypersensitivity to the drug. Patients with acute myocardial infarction and pulmonary. Sick sinus syndrome except in the presence of a functioning ventricular pacemaker. ( 4 ) Second- or third-degree AV block except in the presence of a functioning ventricular pacemaker. ( 4 ) Hypotension (less than 90 mm Hg systolic). ( 4 ) Hypersensitivity to the drug. ( 4 ) Acute myocardial infarction and pulmonary. ( 4 )

The following adverse reactions are described in greater detail, in other sections: Bradycardia and AV block [see Warnings and Precautions (5.1) ] Heart failure [see Warnings and Precautions (5.2) ] Acute hepatic injury [see Warnings and Precautions (5.3) ] Severe skin reactions [see Warnings and Precautions (5.4) ] The most common adverse reactions ( > 2% ) are lower limb edema, sinus congestion and rash in patients treated for hypertension, and lower limb edema, headache, dizziness, fatigue, bradycardia, first-degree AV block and cough in patients treated for angina. ( 6.1 ) To report SUSPECTED ADVERSE REACTIONS, contact ScieGen Pharmaceuticals, Inc. at 1-855-724-3436 or FDA at 1-800-FDA-1088 or www.fda.gov/medwatch . 6.1 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. For the hypertension studies, the following table presents adverse reactions more common on diltiazem than on placebo (but excluding events with no plausible relationship to treatment), as reported in placebo-controlled hypertension trials in patients receiving a diltiazem hydrochloride extended-release formulation (once-a-day dosing) up to 540 mg. Adverse Reactions (MedDRA Term) Placebo Diltiazem hydrochloride extended-release n=120 # pts. (%) 120mg to 360 mg n=501 # pts. (%) 540 mg n=123 # pts. (%) Edema lower limb 4 (3) 24 (5) 10 (8) Sinus congestion 0 (0) 2 (1) 2 (2) Rash 0 (0) 3 (1) 2 (2) In the angina study, the adverse event profile of diltiazem hydrochloride extended-release tablets was consistent with what has been previously described for diltiazem hydrochloride extended-release tablets and other formulations of diltiazem HCl. The most frequent adverse effects experienced by diltiazem hydrochloride extended-release tablets-treated patients were edema lower-limb (6.8%), dizziness (6.4%), fatigue (4.8%), bradycardia (3.6%), first-degree atrioventricular block (3.2%), and cough (2%). In addition, the following events have been reported infrequently (less than 1%) in angina or hypertension trials: Cardiovascular: Angina, bundle branch block, palpitations, syncope, tachycardia, ventricular extrasystoles [see Warnings and Precautions (5.1 , 5.2) ] . 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, thirst, vomiting, weight increase. Dermatological: Petechiae, photosensitivity, pruritus, urticaria [see Warnings and Precautions (5.4) ]. Other: Amblyopia, CPK increase, dyspnea, epistaxis, eye irritation, hyperglycemia, hyperuricemia, impotence, muscle cramps, nasal congestion, nocturia, osteoarticular pain, polyuria, sexual difficulties. 6.2 Post-Marketing Experience The following adverse reactions have been identified during post-approval use of diltiazem. Because these reactions are reported voluntarily from a population of uncertain size, it is not always possible to estimate their frequency or establish a causal relationship to drug exposure. The following post-marketing reactions have been reported infrequently in patients receiving diltiazem: acute generalized exanthematous pustulosis, allergic reactions, alopecia, angioedema (including facial or periorbital edema), erythema multiforme, 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.

Beta-blockers, digitalis, and other agents known to impair cardiac contractility and conduction may increase risk for hypotension, bradycardia, and heart failure. ( 7.1 ) CYP450 3A4: Diltiazem is both a substrate and inhibitor of CYP450 3A4. CYP450 3A4 substrates may require dosage adjustment. ( 7.2 ) 7.1 Agents Known to Impair Cardiac Contractility and Conduction Using other agents known to affect cardiac conduction or contractility with diltiazem may increase the risk of bradycardia, AV block, and heart failure [see Warnings and Precautions (5.1 , 5.2) ]. Ivabradine: Concurrent use of diltiazem increases exposure to ivabradine and may exacerbate bradycardia and conduction disturbances. Avoid concomitant use of ivabradine and diltiazem. 7.2 P-glycoprotein (P-gp) and Cytochrome P450 3A4 Mediated Drug Interactions Diltiazem is both a substrate and an inhibitor of the Pg-p and cytochrome P450 3A4 enzyme system which may affect exposure to diltiazem and concomitant drugs metabolized by those pathways. Patients with renal and/or hepatic impairment may be particularly at risk of exposure changes [see Clinical Pharmacology (12.3) ].

Storage conditions: Store at 20°C to 25°C (68°F to 77°F); excursions permitted between 15°C to 30°C (59°F to 86°F) [see USP Controlled Room Temperature]. Avoid excessive humidity and temperatures above 30°C (86°F). Dispense in tight, light resistant container as defined in USP.