What is the typical dosing regimen for Diltiazem (Diltiazem) in the management of hypertension or angina?

Diltiazem Dosing Regimen for Hypertension and Angina

For hypertension, diltiazem should be dosed at 180-360 mg once daily using extended-release formulations, with higher doses of 360-480 mg daily often required for optimal blood pressure control. For angina, the recommended dosing is 30-90 mg immediate-release four times daily or 120-360 mg once daily using extended-release formulations 1, 2.

Dosing by Indication

Hypertension

• Starting dose: 180-240 mg once daily (extended-release)
• Maintenance dose: 240-360 mg once daily
• Maximum dose: 480 mg daily
• Note: Research indicates that hypertension typically requires higher doses than angina, commonly 360 mg/day 3

Angina Pectoris

• Immediate-release formulation:
  • Starting dose: 30 mg four times daily (before meals and at bedtime)
  • Titration: Increase gradually at 1-2 day intervals
  • Maintenance dose: 180-360 mg/day divided three or four times daily 2
• Extended-release formulation:
  • Dose: 120-360 mg once daily 4

Formulation Considerations

Immediate-Release Tablets

• May be swallowed whole, crushed, or chewed
• 30 mg tablets should not be split 2

Extended-Release Formulations

• Provide consistent 24-hour blood pressure control
• Improve adherence with once-daily dosing
• Therapeutic blood levels (≥40 ng/mL) achieved with doses ≥240 mg/day 5

Special Populations

Renal/Hepatic Impairment

• No specific dosage recommendations available
• Titrate with particular caution in these patients 2

Monitoring and Adverse Effects

• Common side effects: Hypotension, dizziness, flushing, bradycardia, edema 1, 4
• Monitoring parameters: Blood pressure, heart rate, cardiac conduction, signs of fluid retention 4

Important Contraindications and Cautions

• Contraindicated in: Left ventricular dysfunction (LVEF <40%), decompensated heart failure, AV block greater than first degree, sick sinus syndrome, cardiogenic shock, and pre-excitation syndromes 4
• Use with caution when combining with:
  • Beta-blockers (increased risk of bradycardia and heart block)
  • Nitrates (risk of orthostatic hypotension)
  • Digitalis preparations (potentiation of bradycardia or AV block) 4, 6

Pharmacokinetic Considerations

• Diltiazem exhibits nonlinear pharmacokinetics at higher doses
• Apparent oral clearance decreases with increasing doses
• Plasma concentrations correlate with antihypertensive effects 7, 5

Clinical Pearls

• Diltiazem has a heart rate-regulating effect: it reduces elevated heart rates (≥74 beats/min) without causing excessive bradycardia in patients with normal heart rates 8
• Underdosing is common in hypertension treatment; doses up to 480-540 mg/day show a linear dose-response relationship for blood pressure lowering 3
• When calcium channel blockers are indicated for angina or hypertension, diltiazem may be preferred over dihydropyridines in patients with tachycardia 8