What drug class does diltiazem belong to?

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Diltiazem Drug Class

Diltiazem is a benzothiazepine calcium channel blocker (calcium antagonist), which is one of three distinct subclasses of calcium channel blockers along with dihydropyridines and phenylalkylamines. 1

Classification Details

Calcium channel blockers are divided into three chemically distinct subclasses with differing pharmacological properties 1:

  • Benzothiazepines (such as diltiazem)
  • Dihydropyridines (such as nifedipine, amlodipine)
  • Phenylalkylamines (such as verapamil)

Mechanism of Action

Diltiazem functions as a calcium ion cellular influx inhibitor (slow channel blocker) that blocks L-type calcium channels. 2 The drug works by:

  • Slowing AV nodal conduction and increasing refractoriness 3
  • Causing coronary and peripheral vasodilation 4
  • Producing negative chronotropic (heart rate lowering) and dromotropic (conduction slowing) effects 4
  • Having minimal negative inotropic effects in patients with normal ventricular function 4

Distinguishing Pharmacological Characteristics

Diltiazem is classified as a non-dihydropyridine calcium channel blocker, which distinguishes it from dihydropyridines in several important ways 1:

  • Vasodilatory effects: Diltiazem produces the least peripheral arterial vasodilation among calcium channel blockers, whereas nifedipine and amlodipine produce the most marked vasodilation 1
  • Cardiac effects: Unlike dihydropyridines, diltiazem has significant direct effects on AV conduction and heart rate 1
  • Myocardial depression: Non-dihydropyridine calcium channel blockers (diltiazem and verapamil) are myocardial depressants and generally not well tolerated in heart failure 1

Clinical Implications of Classification

The benzothiazepine classification has important therapeutic implications:

  • All calcium channel blocker subclasses cause similar coronary vasodilation, making them effective for vasospastic angina 1
  • Diltiazem and verapamil show similar efficacy in relieving anginal symptoms and appear equivalent to beta-blockers 1
  • AV block may be induced by non-dihydropyridines (diltiazem and verapamil), requiring caution in patients with conduction abnormalities 1
  • Diltiazem should be avoided in patients with significantly impaired left ventricular function due to its myocardial depressant effects 1

References

1
Guideline

Guideline Directed Topic Overview

Dr.Oracle Medical Advisory Board & Editors, 2025

3
Guideline

Diltiazem Dosing for Rapid Ventricular Response

Praxis Medical Insights: Practical Summaries of Clinical Guidelines, 2026

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Professional Medical Disclaimer

This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.

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