Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0024591 (malignant hyperthermia)
 2,353 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The effects of commonly used intravenous anaesthetic agents ketamine, thiopental sodium and propofol on the caffeine-alone or halothane-plus-caffeine-induced muscle contractures were investigated to determine safety for use in patients susceptible to malignant hyperthermia (MH). The muscle strips from rat diaphragm were exposed to one of these anaesthetic agents prior to challenge with caffeine 8 mmol/l alone or halothane 3% plus caffeine 8 mmol/l together. None of the three agents induced contractures when added alone. Ketamine 100 mumol/l and thiopental sodium 300 mumol/l augmented neither caffeine-alone nor caffeine-with-halothane contractures significantly and these two agents appear to be safe for use in MH-susceptible patients. In contrast, propofol 150 mumol/l augmented these contractile responses significantly and may not be recommended for use in patients known to be susceptible to this anaesthetic complication.
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PMID:Effects of ketamine, thiopental sodium and propofol on muscle contractures in rat diaphragm in vitro. 174 5

Since ketamine has been incriminated as triggering malignant hyperthermia (MH) [3, 9, 13, 14, 18], but has still been used uneventfully in MH susceptible patients, we performed an in vitro study to examine the safety of ketamine for use in human MH. METHODS. Muscle specimens of 20 patients who had muscle biopsies to diagnose MH were investigated. In every patient diagnostic contracture tests (2 halothane (Hal) and 2 caffeine (Caf) were done according to the protocol established by the European MH group (EMHG). In addition, one test unit for investigating the effect of stepwise increased bath-concentrations of ketamine (5, 10, 20, 60, 120, 240 and 960 mumol/l) and a further one serving as control (no drugs added to the bath) were used. Combined Hal (2 vol%) and Ket (960 mumol/l) tests were performed in 9 patients (4 MHS, 4 MHN, 1 MHEh). Changes in baseline contractures and mechanical twitch tension were evaluated. RESULTS. The diagnostic test showed MHS in 8, MHN in 8 and MHEh in 4 patients. Ketamine did not induce baseline contractures in any of the tests performed. Contractures induced by 2 vol% of halothane in 4 MHS muscles did not change significantly when ketamine was added to the bath (concentration 960 mumol/l). A significant, dose-related decrease in mechanical twitch tension occurred, when ketamine was added to the test. At the highest concentration (960 mumol) twitch tension was reduced by 55%. Twitch tension remained stable in untreated muscles. No significant differences were found between the specimens from MHS, MHN and MHE patients. This reduction in twitch tension was more pronounced in specimens exposed to both halothane (2 vol%) and ketamine (960 mumol/l), resulting in an average decrease of 71%. CONCLUSION. In accordance with Fletcher et al., our results indicate that ketamine - at least in vitro - does not trigger MH. In MHS muscles, ketamine does not augment halothane-induced baseline contractures. The ketamine-induced reduction of mechanical twitch tension in directly stimulated human muscles has not been described before. Analogous findings in frog sartorius muscles can be found in the literature. Whereas the effect of ketamine on indirectly stimulated muscle has been investigated by several authors, the underlying mechanism of ketamine-induced twitch suppression in directly stimulated muscles is not known. Inhibition of calcium release from or accelerated uptake into the sarcoplasmatic reticulum have been reported.
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PMID:[The action of ketamine on muscle contractile behavior. In vitro studies on the musculature of subjects susceptible to malignant hyperthermia]. 261 30