Diltiazem ER
CARDIZEM CD
What it isDiltiazem extended-release (CARDIZEM CD, 1991) blocks L-type calcium channels; hypertension and chronic stable angina.
Why this oneThe once-daily form replaces an IR tablet dosed 3-4x daily; it usually causes less constipation and myocardial depression than verapamil.
What limits itBradycardia, heart block and edema limit it; avoid systolic heart failure. CYP3A4 inhibition raises many statin and other substrate exposures.
FDA-approved for
- hypertension (1991)
- chronic stable angina (1991)
FDA label
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| FDA dosing | Population | Start | Target | Max |
|---|---|---|---|---|
| Hypertension | Adults | 180-240 mg QD (monotherapy) | 240-360 mg QD | 480 mg QD |
| Chronic stable angina / angina due to coronary artery spasm | Adults | 120 or 180 mg QD | individualize | 480 mg QD |
Titration Hypertension: maximum effect usually by 14 days; schedule adjustments accordingly. Angina: titrate over a 7- to 14-day period
Renal Undefined
Hepatic Increased half-life and ~69% higher bioavailability in cirrhosis; titrate cautiously (start low)
Instructions
- Once-daily extended-release capsule
- Patients controlled on diltiazem may switch to ER at nearest equivalent total daily dose
- Avoid consumption of alcohol (may accelerate diltiazem release)
Contraindications
- Sick sinus syndrome except with a functioning ventricular pacemaker
- Second- or third-degree AV block except with a functioning ventricular pacemaker
- Hypotension (less than 90 mm Hg systolic)
- Acute myocardial infarction and pulmonary congestion documented by x-ray on admission
Cautions
- Cardiac conduction: prolongs AV node refractory period; may cause bradycardia or AV block (additive with beta-blockers/digitalis)
- Congestive heart failure — worsening reported with pre-existing ventricular impairment
- Hypotension
- Acute hepatic injury (usually transient transaminase elevations)
- Dermatologic reactions (may progress to erythema multiforme/exfoliative dermatitis)
Adverse reactions
- Headache, dizziness, bradycardia, first-degree AV block, edema, asthenia
Pregnancy Animal studies showed embryo/fetal lethality and skeletal abnormalities; use only if potential benefit justifies risk
Lactation Diltiazem excreted in human milk (may approximate serum levels); use alternative feeding if drug essential
NO BOXED WARNINGS
Principal riskBradycardia and heart block; a potent CYP3A4 inhibitor
Classes and tags
Clinical profile
Mechanism of action: Diltiazem ER ballicule
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