Essential tremor, beta-blockers, and calcium channel blockers

To the Editor: In their thorough review of essential tremor,¹Drs. Abboud, Ahmed, and Fernandez make a statement that needs clarification. In their list of absolute contraindications to propranolol (Inderal), the authors include “concurrent use of a calcium channel blocker.” This warning applies only to the nondihydropyridine calcium channel blockers, which are diltiazem (Cardizem) and verapamil (Calan). These two medications slow the heart rate and generally should not be combined with beta-blockers such as propranolol unless the patient requires this combination to control tachycardia. Most calcium channel blockers are dihydropyridines, which include amlodipine (Norvasc), nifedipine (Procardia), felodipine (Plendil), nisoldipine (Sular), isradipine (DynaCirc CR), and nicardipine (Cardene). These agents do not slow the heart rate significantly and therefore can be used freely in combination with propranolol. Of course, the dose of the calcium channel blocker may need to be decreased because of the antihypertensive effect of propranolol.