Myasthenia Gravis

To the Editor: In his review on myasthenia gravis, Gilhus (Dec. 29 issue) 1 recommends against prescribing muscle relaxants, penicillamine, and certain antibiotics to patients with the disorder. The use of beta-blockers and calcium-channel blockers in myasthenia gravis, however, is controversial. This is relevant in the management of atrial fibrillation, the most common adult cardiac arrhythmia. At least three cases of beta-blockade precipitating and worsening myasthenic syndromes have been reported 2 ; however, propranolol has been administered safely to participants in a small study. 3 The effect of selective beta-blockers such as atenolol and metoprolol on neuromuscular transmission in patients with myasthenia gravis . . .