Heart Rhythm Drugs - Class IV - Calcium Channel Blockers

Are calcium channel blockers beneficial?

In general, class IV agents, (calcium channel blockers, or CCBs), do not reduce the risk of dying in people who have had a heart attack or have unstable angina (chest pain), and in some cases they do more harm than good. For this reason they are no longer routinely prescribed after a heart attack. There are two types of CCBs: the dihydropyridines (such as amlodipine and nifedipine) are harmful in heart attack patients.³² The other type, non-dihydropyridines (such as verapamil and diltiazem) may be harmful in patients who have chronic heart failure, a very slow irregular heartbeat (bradyarrhythmia), or lung problems.^33-36 In heart attack patients who do not have these conditions, verapamil (Covera or Verelan) reduces the risk of dying or suffering further heart problems,³⁷ and diltiazem (Cardizem or Tiazac) lowers the risk of having another heart attack.^{38, 39} These particular CCBs may be used for the short-term treatment of arrhythmias in heart attack patients who cannot take beta blockers.³ Many CCBs come in a short-acting and a long-acting (sustained release) form. Short-acting CCBs increase the risk of heart attack and stroke when used over an extended period.⁴⁰

Prescribed Class IV Antiarrhythmics