Diltiazem hydrochloride
Diltiazem hydrochloride (Cardizem)
Diltiazem hydrochloride
(dill- TIE-ah-zem)
Pregnancy Category: C Alti-Diltiazem Alti-Diltiazem CD Apo-Diltiaz Apo-Diltiaz CD Cardizem Cardizem CD Cardizem Injectable Cardizem Lyo-Ject Cardizem-SR Cartia XT Dilacor XR Diltiazem HCl Extended Release Gen-Diltiazem Med Diltiazem Novo-Diltazem Novo-Diltazem SR Nu-Diltiaz Taro-Diltiazem Tiamate Tiazac (Rx)

Classification: Calcium channel blocking agent (antianginal, antihypertensive)

See Also: See also Calcium Channel Blocking Agents .

Action/Kinetics: Decreases SA and AV conduction and prolongs AV node effective and functional refractory periods. Also decreases myocardial contractility and peripheral vascular resistance. Tablets: Onset, 30-60 min; time to peak plasma levels: 2-3 hr; t 1/2, first phase: 20-30 min; second phase: about 3-4.5 hr (5-8 hr with high and repetitive doses); duration: 4-8 hr. Extended-Release Capsules: Onset, 2-3 hr; time to peak plasma levels: 6-11 hr; t 1/2: 5-7 hr; duration: 12 hr. Therapeutic serum levels: 0.05-0.2 mcg/mL. Metabolized to desacetyldiltiazem, which manifests 25%-50% of the activity of diltiazem. Excreted through both the bile and urine.

Uses: Tablets: Vasospastic angina (Prinzmetal's variant). Chronic stable angina (classic effort-associated angina), especially in clients who cannot use beta-adrenergic blockers or nitrates or who remain symptomatic after clinical doses of these agents. Sustained-Release Capsules: Essential hypertension, angina. Parenteral: Atrial fibrillation or flutter. Paroxysmal SVT. Cardizem Lyo-Ject is used on an emergency basis for atrial fibrillation or atrial flutter. Cardizem Monovial is used to maintain control of HR for up to 24 hr in atrial fibrillation or flutter. Investigational: Prophylaxis of reinfarction of nonQ wave MI; tardive dyskinesia, Raynaud's syndrome.

Contraindications: Hypotension. Second- or third-degree AV block and sick sinus syndrome except in presence of a functioning ventricular pacemaker. Acute MI, pulmonary congestion. Lactation.

Special Concerns: Safety and effectiveness in children have not been determined. The half-life may be increased in geriatric clients. Use with caution in hepatic disease and in CHF. Abrupt withdrawal may cause an increase in the frequency and duration of chest pain. Use with beta blockers or digitalis is usually well tolerated, although the effects of coadministration cannot be predicted (especially in clients with left ventricular dysfunction or cardiac conduction abnormalities).

Side Effects: CV: AV block, bradycardia, CHF, hypotension, syncope, palpitations, peripheral edema, arrhythmias angina, tachycardia, abnormal ECG, ventricular extrasystoles. GI: N&V;, diarrhea, constipation, anorexia, abdominal discomfort, cramps, dry mouth, dysgeusia. CNS: Weakness, nervousness, dizziness, lightheadedness, headache, depression, psychoses, hallucinations, disturbances in sleep, somnolence, insomnia, amnesia, abnormal dreams. Dermatologic: Rashes, dermatitis, pruritus, urticaria, erythema multiforme, Stevens-Johnson syndrome. Other: Photosensitivity, joint pain or stiffness, flushing, nasal or chest congestion, dyspnea, SOB, nocturia/polyuria, sexual difficulties, weight gain, paresthesia, tinnitus, tremor, asthenia, gynecomastia, gingival hyperplasia, petechiae, ecchymosis, purpura, bruising, hematoma, leukopenia, double vision, epistaxis, eye irritation, thirst, alopecia, bundle branch block abnormal gait, hyperglycemia.

Laboratory Test Alterations: Alkaline phosphatase, CPK, LDH, AST, ALT.

Additional Drug Interactions: Anesthetics / Risk of depression of cardiac contractility, conductivity, and automaticity as well as vascular dilation Carbamazepine / Diltiazem effect R/T liver breakdown Cimetidine / Diltiazem bioavailability Cyclosporine / Cyclosporine effect possible renal toxicity Digoxin / Possible serum digoxin levels Lithium / Risk of neurotoxicity Ranitidine / Diltiazem bioavailability Theophyllines / Risk of pharmacologic and toxicologic theophylline effects

How Supplied: Capsule, Extended Release: 60 mg, 90 mg, 120 mg, 180 mg, 240 mg, 300 mg, 360 mg; Injection: 5 mg/mL; Monovial: 100 mg freeze-dried diltiazem; Powder for Injection: 10 mg, 25 mg; Tablet: 30 mg, 60 mg, 90 mg, 120 mg; Tablet, Extended Release: 120 mg, 180 mg, 240 mg

Dosage
?Tablets Angina.
Adults, initial: 30 mg q.i.d. before meals and at bedtime; then, increase gradually to total daily dose of 180-360 mg (given in three to four divided doses). Increments may be made q 1-2 days until the optimum response is attained.
?Capsules, Sustained-Release Angina.
Cardizem CD: Adults, initial: 120 or 180 mg once daily. Up to 480 mg/day may be required. Dosage adjustments should be carried out over a 7-14-day period.
Dilacor XR: Adults, initial: 120 mg once daily; then dose may be titrated, depending on the needs of the client, up to 480 mg once daily. Titration may be carried out over a 7-14-day period.
Hypertension.
Cardizem CD: Adults, initial: 180-240 mg once daily. Maximum antihypertensive effect usually reached within 14 days. Usual range is 240-360 mg once daily.
Cardizem SR: Adults, initial: 60-120 mg b.i.d.; then, when maximum antihypertensive effect is reached (approximately 14 days), adjust dosage to a range of 240-360 mg/day.
Dilacor XR: Adults, initial: 180-240 mg once daily. Usual range is 180-480 mg once daily. The dose may be increased to 540 mg/day with little or no increased risk of side effects.
Tiazac: Adults, initial: 120-240 mg once daily. Usual range is 120-360 mg once daily, although doses up to 540 mg once daily have been used.
?IV Bolus Atrial fibrillation/flutter; paroxysmal SVT.
Adults, initial: 0.25 mg/kg (average 20 mg) given over 2 min; then, if response is inadequate, a second dose may be given after 15 min. The second bolus dose is 0.35 mg/kg (average 25 mg) given over 2 min. Subsequent doses should be individualized. Some clients may respond to an initial dose of 0.15 mg/kg (duration of action may be shorter).
?IV Infusion Atrial fibrillation/flutter.
Adults: 10 mg/hr following IV bolus dose(s) of 0.25 mg/kg or 0.35 mg/kg. Some clients may require 5 mg/hr while others may require 15 mg/hr. Infusion may be maintained for 24 hr.
?Cardizem Lyo-Ject Atrial fibrillation/atrial flutter.
Delivery system consists of a dual-chamber, prefilled, calibrated syringe containing 25 mg of diltiazem hydrochloride in one chamber and 5 mL of diluent in the other chamber.