Acetazolamide-induced weakness in paramyotonia congenita.

Acetazolamide has been shown to be effective prophylaxis for both hypokalemic and hyperkalemic paralysis. A patient with paramyotonia congenita, a related disorder with myotonia and episodic weakness, was studied during treatment with acetazolamide. Athough the patient's myotonia was virtually abolished, severe quadriparesis was produced during each trial of acetazolamide. This response distinguished this patient's condition from other forms of familial periodic paralysis and suggests that acetazolamide may be deleterious to some patients with periodic paralysis.