Effects of enzyme induction, renal and cardiac function on ketamine plasma kinetics in patients with ketamine long-term analgosedation
Steady-state plasma levels of ketamine and its metabolites norketamine and dehydronorketamine were determined in 4 different groups of a total of 27 patients with ketamine long-term analgosedation (1.1 – 1.3 mg/kg/h). In 9 of the patients who had normal liver and kidney function (group 1), steady-state levels after 3 days of continuous infusion were 1.2±0.3 μg/ml ketamine, 1.0±0.6 μg/ml norketamine, and 2.6±1.0 μg/ml dehydronorketamine. The measured ketamine levels in group 1 were in agreement with the expected value, which may be calculated from published pharmacokinetic data after bolus injection. In 8 patients with acute renal failure (group 2), a tendency to about 20% higher ketamine steady-state plasma levels compared to group 1 was observed, but this difference was not significant. However, dehydronorketamine plasma levels were significantly higher in this group. Only a manor fraction of the ketamine dose (10% and 4%) was eliminated during hemodialysis or hemofiltration treatment, respectively. Steady-state plasma levels in 5 patients with cardiogenic shock (group 3) did not differ significantly from those of group 1. In 5 patients with long-term use of barbiturates (group 4), steady-state plasma levels of ketamine were significantly lower compared to groups 1 and 3, most likely due to barbiturate-induced enzyme induction.
Hyperdynamic circulatory reactions were not observed in any of the patients. Psychomimetic effects could be excluded in 16 of the patients and were unlikely in 6 patients. In 5 further patients, psychomimetic effects could not definitely be excluded due to difficulties in non-verbal communication.
KeywordsKetamine long-term analgosedation plasmakinetics kidney liver heart function
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- 2.Dick W., Gervais H., (1986): Analgesie bei Notfallpatienten. Anästh. Intensivmed., 27, 1–8.Google Scholar
- 4.Kurth M., (1983): Anästhesie und Analgose dierung, mit Ketamin bei Patienten einer Intensivstation. Anästh. Intensivmed., 24, 270–272.Google Scholar
- 5.Schürmann W., Pfenninger E., Ahnefeld F.W., (1984): Welche Rolle spielt Ketamin in der Notfallmedizin. Notfallmedizin, 10, 1435–1448.Google Scholar
- 11.Chen C., (1969): The pharmacology of ketamine. In: Kreuschner H. (ed.) Ketamine (Anaesthesiologie und Wiederbelebung, Vol. 40). Berlin, Springer, p. 1.Google Scholar
- 20.Martens F., Köppel C., (1990): PHARM — Ein Programm zur Berechhung pharmakokinetischer Parameter bei Intensivpatienten auf Personalcomputern. Intensivmed., 27, 107–111.Google Scholar