title: Treatment of "permanent" muscle weakness in familial Hypokalemic Periodic Paralysis.
abstract: Three patients with Hypokalemic Periodic Paralysis (HOPP)-associated progressive interattack muscle weakness, who became unresponsive or worsened by acetazolamide, responded favorably to dichlorophenamide, a more potent carbonic anhydrase inhibitor. Dichlorophenamide in single-blind placebo-controlled trials, considerably improved functional strength in two of the patients and had a moderate but definite effect in the third. Muscle groups graded 4/5 (MRC scale)returned to normal; very weak (0-3/5) atrophic muscles, improved to a minor degree. In one patient with acetazolamide-resistant paralytic attacks, dichlorophenamide also diminished the frequency and severity of the acute attacks. Dichlorophenamide had, in the present study, less effect than acetazolamide in reducing serum HCO3(-) and elevating Cl-. Its effectiveness may be related to the degree of sensitivity of certain HOPP patients to alterations of Cl- and/or HCO3(-) serum levels or to a different action of the drug unrelated to carbonic anhydrase inhibition or acidosis. Dichlorophenamide should be considered as an alternate to acetazolamide in the treatment of patients with HOPP-associated interattack muscle weakness who have become unresponsive or worsened by acetazolamide.
mesh_terms: D000328:Adult; D004005:Dichlorphenamide / Q000494:pharmacology / Q000627:therapeutic use*; D006801:Humans; D007008:Hypokalemia / Q000150:complications / Q000188:drug therapy*; D008297:Male; D008875:Middle Aged; D009132:Muscles / Q000187:drug effects; D009133:Muscular Atrophy / Q000188:drug therapy* / Q000473:pathology; D010245:Paralyses, Familial Periodic / Q000188:drug therapy* / Q000209:etiology / Q000473:pathology
chemical_list: D004005:Dichlorphenamide