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Name: Verapamil hydrochloride

Pregnancy Category C

Drug classes

  • Calcium channel-blocker
  • Antianginal drug
  • Antiarrhythmic drug
  • Antihypertensive

Therapeutic actions

Inhibits the movement of calcium ions across the membranes of cardiac and arterial muscle cells; calcium is involved in the generation of the action potential in specialized automatic and conducting cells in the heart, in arterial smooth muscle, and in excitation-contraction coupling in cardiac muscle cells; inhibition of transmembrane calcium flow results in the depression of impulse formation in specialized cardiac pacemaker cells, slowing of the velocity of conduction of the cardiac impulse, the depression of myocardial contractility, and the dilation of coronary arteries and arterioles and peripheral arterioles; these effects lead to decreased cardiac work, decreased cardiac energy consumption, and in patients with vasospastic (Prinzmetal's) angina, increased delivery of oxygen to myocardial cells.


  • Angina pectoris due to coronary artery spasm (Prinzmetal's variant angina)
  • Effort-associated angina
  • Chronic stable angina in patients who cannot tolerate or do not respond to beta-adrenergic blockers or nitrates
  • Unstable, crescendo, preinfarction angina
  • Essential hypertension (sustained-release oral)
  • Treatment of supraventricular tachyarrhythmias (parenteral)
  • Temporary control of rapid ventricular rate in atrial flutter or atrial fibrillation (parenteral)
  • Unlabeled oral uses: paroxysmal supraventricular tachycardia, migraine headache, nocturnal leg cramps, hypertrophic cardiomyopathy


Contraindicated in the presence of allergy to verapamil; sick sinus syndrome, except in presence of ventricular pacemaker; heart block (second- or third-degree); hypotension; pregnancy; lactation.

Use caution in the presence of idiopathic hypertrophic subaortic stenosis, cardiogenic shock, severe CHF, impaired renal or hepatic function.

Adverse effects

  • CNS: Dizziness, vertigo, emotional depression, sleepiness, headache
  • GI: Nausea, constipation
  • CV: Peripheral edema, hypotension, arrhythmias, bradycardia; AV heart block
  • Other: Muscle fatigue, diaphoresis

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