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心律不整、心絞痛、高血壓 Atrial arrhythmia, hypertension, paroxysmal supraventricular tachycardia (PSVT), chronic stable angina

Antiarrhythmic Agent, Class IV; Calcium Channel Blocker, Nondihydropyridine
Diltiazem hydrochloride is a slow calcium channel blocker that blocks calcium ion influx during depolarization of cardiac and vascular smooth muscle. It decreases peripheral vascular resistance and causes relaxation of the vascular smooth muscle resulting in a decrease of both systolic and diastolic blood pressure.

1. Distribution: Vd 305-391 L
2. Metabolism: Hepatic; cytochrome P450, extensive, deacetylation, N-demethylation, O-demethylation, and conjugation
3. Excretion: (Renal) 2% to 4% unchanged
4. Elimination Half Life: 3.4-4.9 h

1. Acute MI with pulmonary congestion on x-ray.
2. Administration of IV beta-blockers within a few hours of IV diltiazem.
3. Atrial fibrillation or flutter associated with an accessory bypass tract (Wolff-Parkinson-White or short PR syndromes); risk of potentially fatal heart rate fluctuations.
4. Cardiogenic shock.
5. Heart block, second or third-degree atrioventricular without a functioning ventricular pacemaker.
6. Hypersensitivity to diltiazem.
7. Sick sinus syndrome without a functioning ventricular pacemaker.
8. Symptomatic hypotension, systolic blood pressure 90 mmHg or less.
9. Ventricular tachycardia; may lead to hemodynamic deterioration and ventricular fibrillation.

C (FDA)

Infant risk is minimal (MDX). Maternal medication usually compatible with breastfeeding (AAP).

Common:
Bradyarrhythmia, peripheral edema, dizziness, headache, cough, fatigue
Serious:
Congestive heart failure, heart block, myocardial infarction, hepatotoxicity

Atrial fibrillation or atrial flutter, rate control:
1. Bolus dose: 0.25 mg/kg over 2 minutes (average dose: 20 mg); if rate control is insufficient after 15 minutes, a repeat bolus dose of 0.35 mg/kg over 2 minutes may be given (average dose: 25 mg). Patients who respond after 1 or 2 bolus doses can be started on a continuous infusion.
2. Continuous infusion following bolus(es): Initial 5-10 mg/hour; infusion rate may be increased in 5 mg/hour increments, up to a maximum of 15 mg/hour; use of a continuous infusion >24 hours or >15 mg/hour is not recommended due to potential for drug accumulation.
Supraventricular tachycardia (alternative agent):
1. Bolus dose: 0.25 mg/kg over 2 minutes (average dose: 20 mg); if response is insufficient after ≥15 minutes, a repeat bolus dose of 0.35 mg/kg over 2 minutes may be given (average dose: 25 mg)
2. Alternative: If bolus(es) do not terminate the arrhythmia, consider alternative therapy

1. Mild to severe impairment: No dosage adjustment necessary
2. Hemodialysis, Peritoneal dialysis, CRRT: Not significantly dialyzed; No supplemental dose or dosage adjustment necessary

There are no dosage adjustments provided in the manufacturer's labeling; use with caution