Adverse effects of drugs on the respiratory muscles.

Over 100 drugs can impair muscle function, either by inhibiting neural drive, causing peripheral neuropathy, blocking neuromuscular junctions, precipitating myasthenia gravis, or producing myopathy. Many of these drugs affect respiratory muscles, particularly the diaphragm. Although a great deal is known about the drug effects on central respiratory drive and neuromuscular blockade, little is known about the depressant effects of drugs specifically on phrenic nerve function or diaphragm contractility. This article has reviewed what is known about the effects of drugs on respiratory myoneural function and what can be inferred from studies on other striated muscles. We hope that this review serves to stimulate further investigation; meanwhile, until more is known, continued clinical caution is justified.