CLINICAL EFFECTS OF INTRAVENOUSLY ADMINISTERED DANTROLENE

Objective: To compare side effects after intravenous administration of dantrolene sodium in subjects susceptible to and those nonsusceptible to malignant hyperthermia (MHS and MHN, respectively). Design: We stu died two groups, six patients thought to be MHS and six assumed MHN su bjects, and analyzed their responses to intravenously administered dan trolene. Material and Methods: Dantrolene (3 mg/kg) was administered s lowly into an antecubital vein, and blood samples were withdrawn from the other arm at 5 and 25 minutes after infusion, Shortly thereafter, all subjects underwent a clinical neurologic assessment, and side effe cts were graded subjectively by the study participants. Results: Side effects occurred in all subjects, Visual symptoms occurred more common ly in MHN than in MHS subjects, Subjective muscle weakness of the extr emities, dizziness, and fatigue occurred more commonly and were more s evere in MHS patients than in MHN subjects. Conclusion: In patients re covering from an episode of malignant hyperthermia for which dantrolen e has been administered, these side effects should be considered, Alth ough the presence of side effects does not outweigh the usefulness of this drug in treating malignant hyperthermia, it mag be a consideratio n in deciding whether to administer dantrolene prophylactically before surgical procedures in known or suspected MHS patients.