PROCAINAMIDE-INDUCED MYASTHENIA-LIKE WEAKNESS AND DYSPHAGIA

A 64-year-old man with chronic renal insufficiency was hospitalized wi th dysphagia and inability to keep his head erect 11 months after begi nning procainamide hydrochloride (PA) for control of atrial flutter. E valuation revealed esophageal dysmotility, worsening renal function, a nd elevated serum PA and N-acetylprocainamide (NAPA) concentrations. N o evidence of autoimmune myasthenia gravis was found. PA was discontin ued and normalization of PA and NAPA concentrations was associated wit h a decrease in muscle weakness and resolution of dysphagia. The corre lation between clinical findings and serum concentrations of PA and NA PA suggests that drug excess due to impaired clearance was the basis f or this unusual adverse drug reaction.