Diltiazem dosage, side effects

Diltiazem dosage, side effects:

Diltiazem is a calcium channel blocker (CCB) used primarily to treat hypertension (high blood pressure), angina (chest pain), and certain heart rhythm disorders (e.g., atrial fibrillation). Below is a comprehensive overview of diltiazem, including its brand names, uses, mechanism, side effects, and more.

Brand Names of Diltiazem

Diltiazem is sold under various brand names worldwide, including:

United States & Canada:

Cardizem (immediate-release, CD, LA, SR formulations)
Tiazac (extended-release)
Cartia XT (extended-release)
Dilt-CD, Dilt-XR, Diltia XT (generic extended-release versions)
Dilacor XR (discontinued in some regions)

Europe & Other Regions:

Dilzem (UK, Europe)
Tildiem (France, Spain, others)
Angitil (some European countries)
Herbesser (Japan, some Asian countries)

Generic Forms:

Available widely as diltiazem hydrochloride in immediate-release (IR), sustained-release (SR), and extended-release (ER/XR) formulations.

Mechanism of Action

Diltiazem is a non-dihydropyridine calcium channel blocker that works by:

Inhibiting calcium influx into vascular smooth muscle and cardiac cells.
Dilating blood vessels (reducing blood pressure).
Slowing heart rate (negative chronotropy) and reducing myocardial oxygen demand (helping angina).

Therapeutic Uses

Hypertension (high blood pressure) – First-line treatment.
Chronic Stable Angina – Reduces chest pain by improving blood flow.
Atrial Fibrillation/Flutter – Controls heart rate (not rhythm).
Vasospastic (Prinzmetal’s) Angina – Prevents coronary artery spasms.

Dosage Forms

Immediate-Release (IR): 30 mg, 60 mg, 90 mg, 120 mg (taken 3–4 times daily).
Sustained-Release (SR, CD, XR): 120 mg, 180 mg, 240 mg, 300 mg (once or twice daily).
Extended-Release (Tiazac, Dilacor XR): 120 mg, 180 mg, 240 mg, 300 mg, 360 mg (once daily).
Intravenous (IV): Used in hospitals for acute heart rate control.

Common Side Effects

Cardiovascular: Bradycardia (slow heart rate), edema (swelling), hypotension.
Gastrointestinal: Nausea, constipation.
CNS: Dizziness, headache, fatigue.
Skin: Rash (rare).

Serious Side Effects & Warnings

Heart block (contraindicated in 2nd/3rd-degree AV block without a pacemaker).
Heart failure exacerbation (use cautiously in patients with reduced ejection fraction).
Liver toxicity (monitor LFTs in hepatic impairment).
Drug interactions:
- Beta-blockers (risk of severe bradycardia).
- Digoxin (increased digoxin levels).
- CYP3A4 inhibitors (e.g., erythromycin, grapefruit juice – increases diltiazem levels).

Contraindications

Severe hypotension.
Sick sinus syndrome (unless pacemaker present).
Acute heart failure with pulmonary congestion.
Pregnancy (Category C – use only if benefits outweigh risks).

Key Considerations

Monitor BP and heart rate regularly.
Do not crush or chew ER tablets (can cause rapid release).
Grapefruit interaction – Avoid (increases drug concentration).

Conclusion

Diltiazem is a versatile calcium channel blocker with multiple brand-name and generic formulations. It’s effective for hypertension, angina, and heart rate control but requires caution in patients with conduction disorders or heart failure. Always consult a healthcare provider for proper dosing and monitoring.