What is the typical dosing of diltiazem (calcium channel blocker) for hypertension or angina?

Diltiazem Dosing for Hypertension and Angina

For hypertension and angina, diltiazem is typically dosed at 120-360 mg daily, with hypertension often requiring higher doses (up to 360 mg daily) compared to angina (typically 240 mg daily). 1, 2

Dosing Guidelines

Oral Dosing

• Initial dose: 120 mg daily in divided doses or as a single dose with long-acting formulations 1
• Maximum maintenance dose: 360 mg daily in divided doses or as a single dose with long-acting formulations 1
• Hypertension: Often requires higher doses (240-360 mg daily) for optimal blood pressure control 2, 3
• Angina: Usually effective at 180-240 mg daily, though some patients may require up to 360 mg daily 4

Extended-Release Formulations

• Once-daily formulations (CD/XR): Provide 24-hour blood pressure control with improved compliance 5, 3
• Twice-daily formulations (SR): Equally effective but require twice-daily administration 5
• Dose titration: Start with lower doses (120-180 mg daily) and titrate upward based on clinical response 3

Contraindications and Precautions

Avoid in patients with:

• AV block greater than first degree or SA node dysfunction (without pacemaker) 1, 6
• Hypotension 1, 6
• Decompensated systolic heart failure or severe LV dysfunction 1
• Wolff-Parkinson-White (WPW) syndrome with atrial fibrillation/flutter 1, 6

Drug Interactions:

• Diltiazem is a substrate of CYP3A4 (major) and a moderate CYP3A4 inhibitor 1
• Use caution with: apixaban, itraconazole, bosutinib, ceritinib, cilostazol, cyclosporine, everolimus, ibrutinib, idelalisib, ivabradine, lomitapide, olaparib, ranolazine, rifampin, simeprevir 1

Potential Adverse Effects

• Hypotension (most common) 1, 6
• Worsening heart failure in patients with pre-existing ventricular dysfunction 1, 6
• Bradycardia 1, 6
• Abnormal liver function tests (rare) 1
• Acute hepatic injury (rare) 1
• Peripheral edema (especially at higher doses) 4

Clinical Pearls

• Dose-response relationship is linear through the 480-540 mg/day range for hypertension 2
• 90-120 mg/day range is considered the "no-effect dose" for hypertension 2
• Diltiazem is often underdosed for hypertension; when properly dosed, it can be highly effective 2, 3
• For angina, diltiazem works through reduction in myocardial oxygen demand and increased supply via coronary artery dilation 4
• When using extended-release formulations, plasma concentrations ≥40 ng/mL are considered within therapeutic range 3
• Caution regarding orthostatic hypotension when combining high-dose diltiazem with nitrate therapy 4

Monitoring

• Blood pressure and heart rate 1
• Signs and symptoms of heart failure in at-risk patients 1
• Liver function tests if clinically indicated 1
• ECG monitoring in patients with conduction system disease 1