Metabolic effects as a cause of myotoxic effects of fluoroquinolones

OBJECTIVES: To investigate if fluoroquinolones (FQs) influence skeletal muscle metabolism of healthy and malignant hyperthermia susceptible (MHS) pigs. MATERIALS AND METHODS: After approval from of the Animal Care Committee, 10 MHS pigs, and 6 MHS pigs were anesthetized with hemodynamic and systemic metabolic monitoring. Microdialysis catheters were placed intramuscularly. After equilibration, levofloxacin and ciprofloxacin were injected as a rapid bolus and continuous infusions. Lactate was measured in the dialysate and statistically analyzed was done (Wilcoxon-test; U-test; P < 0.05). RESULTS: There were no differences in age, weight, and baseline lactate levels between the groups. Both applications of levofloxacin- and ciprofloxacin-induced an increase of local lactate levels in healthy and MHS pigs. No difference between the two groups was observed. CONCLUSION: FQs influence skeletal muscle metabolism. Myotoxic effects of FQs can, therefore, be explained by an influence on the cellular energy balance.