European journal of clinical pharmacology
-
Eur. J. Clin. Pharmacol. · Feb 2000
Randomized Controlled Trial Clinical TrialHaemodynamic interactions between the novel calcium sensitiser levosimendan and isosorbide-5-mononitrate in healthy subjects.
The new calcium sensitiser levosimendan also possesses vasodilatory effects due to potassium-channel opening. The aim of the present study was to assess the possible haemodynamic interactions between levosimendan and isosorbide-5-mononitrate in young healthy men. ⋯ No major additive haemodynamic effects of the combination of levosimendan and isosorbide-5-mononitrate compared with each drug alone could be observed at rest. However, during an orthostatic test, the circulatory response was significantly potentiated with the combination, and three of the subjects were unable to stand upright for the stipulated time.
-
Eur. J. Clin. Pharmacol. · Feb 2000
Randomized Controlled Trial Clinical TrialHuman halothane metabolism, lipid peroxidation, and cytochromes P(450)2A6 and P(450)3A4.
Halothane undergoes both oxidative and reductive metabolism by cytochrome P450 (CYP), respectively causing rare immune-mediated hepatic necrosis and common, mild subclinical hepatic toxicity. Halothane also causes lipid peroxidation in rodents in vitro and in vivo, but in vivo effects in humans are unknown. In vitro investigations have identified a role for human CYPs 2E1 and 2A6 in oxidation and CYPs 2A6 and 3A4 in reduction. The mechanism-based CYP2E1 inhibitor disulfiram diminished human halothane oxidation in vivo. This investigation tested the hypotheses that halothane causes lipid peroxidation in humans in vivo, and that CYP2A6 or CYP3A4 inhibition can diminish halothane metabolism. ⋯ These results provide the first evidence for halothane-dependent lipid peroxidation in humans. Methoxsalen effects on halothane oxidation confirm in vitro results and suggest limited CYP2A6 participation in vivo. CYP2A6-mediated, like CYP2E1-mediated human halothane oxidation, can be inhibited in vivo by mechanism-based CYP inhibitors. In contrast, clinical halothane reduction and lipid peroxidation were not amenable to suppression by CYP inhibitors.