Comparisons between Beta Blockers and Calcium Entry Blockers

Abstract

In cardiology and related areas, if the decade of the 70’s could be called the decade of the beta blockers, there are those who believe that the decade of the 80’s will be called the decade of the calcium entry blockers.^1,2 Recently, 11 separate beta adrenergic blocking agents were licensed in Great Britain.³ As of this writing, there are five beta adrenergic blocking agents licensed in the United States, only one of which, namely propranolol, is licensed for intravenous use in this country (see Table 1). Many of your patients will be, nowadays, taking some of these “new generation” beta blockers An important point to make with respect to beta blockers compared to calcium entry blockers is that the beta blockers are, essentially, very similar drugs. By this I mean that if a drug is classified a beta adrenergic blocking agent, then its effect is known and predictable. It is a “negative” drug. It removes adrenergic influence on myocardium, blood vessels, and, if it crosses the blood brain barrier, on the brain itself. Beta adrenergic blockers are not, directly, in the dosages prescribed either orally or intravenously, negative inotropic or chronotropic agents. If the administration of a beta adrenergic blocking agent reduces heart rate and/or contractility, it is via reduction of adrenergi influence. In this sense, the beta adrenergic blockers are analogous to atropine which also has no influence other than the removal of cholinergic activity at least in reasonable doses.