title: Effect of cocaine on the contracture response to 1% halothane in patients undergoing diagnostic muscle biopsy for malignant hyperthermia.
abstract: Two case reports have cited the recreational use of cocaine as possible trigger of a malignant hyperthermia (MH) crisis. We evaluated whether toxic concentrations of cocaine altered the in vitro muscle response to halothane during contracture tests for MH. Twenty-two patients were studied. Muscle biopsies were obtained and first tested for MH susceptibility with 3% halothane and caffeine contracture testing. Ten patients were diagnosed as MH-susceptible and 12 as MH non-susceptible, in accordance with the North American Malignant Hyperthermia Group protocol. Then, muscle strips were exposed to 1% halothane in the presence and absence of 0.1 mmol.L-1 cocaine. Cocaine alone did not affect baseline muscle tension in either group. With 1% halothane, MH non-susceptible muscle showed no contracture with or without cocaine. In contrast, in the presence of 1% halothane, MH-susceptible muscle showed either no change in contracture (six patients), an increase (two patients), or a decrease (two patients) when exposed to cocaine. However, the overall effect of cocaine on muscle contracture in the presence of 1% halothane was insignificant in both groups. We conclude that cocaine, even at toxic levels, does not have a direct effect on skeletal muscle contractility and thus is safe for MH-susceptible patients.
authors.affiliation: Division of Anesthesiology, Cleveland Clinic Foundation, OH 44195, USA.
authors.forename: N
authors.initials: N
authors.lastname: Sato
authors.forename: J M
authors.initials: JM
authors.lastname: Brum
authors.forename: H
authors.initials: H
authors.lastname: Mitsumoto
authors.forename: G E
authors.initials: GE
authors.lastname: DeBoer
mesh_terms: D000328:Adult; D001706:Biopsy; D002110:Caffeine; D003042:Cocaine / Q000008:administration & dosage / Q000494:pharmacology*; D003286:Contracture / Q000139:chemically induced* / Q000503:physiopathology; D004198:Disease Susceptibility; D005260:Female; D006221:Halothane / Q000009:adverse effects*; D006801:Humans; D008297:Male; D008305:Malignant Hyperthermia / Q000175:diagnosis* / Q000473:pathology / Q000503:physiopathology; D009119:Muscle Contraction / Q000187:drug effects; D018482:Muscle, Skeletal / Q000187:drug effects / Q000473:pathology
chemical_list: D002110:Caffeine; D003042:Cocaine; D006221:Halothane