Inhibitory Effects of Propofol on Cytochrome P450 Activities in Rat Hepatic Microsomes

• Published in: Anesthesia and analgesia Vol. 76; no. 4; pp. 817 - 821
• Main Authors: Baker, Max T., Chadam, Maria V., Ronnenberg, William C.
• Format: Journal Article
• Language: English
• Published: Hagerstown, MD International Anesthesia Research Society 01.04.1993; Lippincott
• Subjects: Anesthetics. Neuromuscular blocking agents; Aniline Compounds - pharmacology; Animals; Benzphetamine - pharmacology; Biological and medical sciences; Cytochrome P-450 Enzyme Inhibitors; Cytochrome P-450 Enzyme System - metabolism; Enflurane - metabolism; Hydroxylation; Isoniazid - pharmacology; Male; Medical sciences; Methylation; Microsomes, Liver - drug effects; Microsomes, Liver - enzymology; Neuropharmacology; Pharmacology. Drug treatments; Phenobarbital - pharmacology; Propofol - pharmacology; Rats; Rats, Sprague-Dawley; Toluene - pharmacology; Intravenous administration; Rat; Enzyme; Cytochrome P450; Liver; Rodentia; Microsome; Vertebrata; Mammalia; Enzymatic activity; General anesthetic; Animal; Drug-metabolizing enzyme
• ISSN: 0003-2999; 1526-7598
• DOI: 10.1213/00000539-199304000-00024

The effects of propofol on cytochrome P450 activity in rat hepatic microsomes were evaluated to determine the potential influence of this anesthetic on the metabolism of coadministered agents. In microsomes from untreated and isoniazid-treated rats, propofol was a weak inhibitor of enflurane metabolism, inhibiting activity only at 0.35 mM propofol. In contrast, toluene, a related compound, effectively impaired enflurane de-fluorination in microsomes from untreated, and isoniazid- and phenobarbital-treated rats at concentrations as low as 0.025 mM. Propofol, in contrast to toluene, was an effective inhibitor of benzphetamine demethylation where it inhibited this activity at propofol concentrations as low as 0.025 mM in microsomes from phenobarbital-treated rats. In microsomes from phenobarbital-treated rats, propofol potently inhibited the metabolism of aniline. Sixty-four percent inhibition was achieved at 0.03 mM propofol, whereas toluene had no effect at 1 mM. These data demonstrate that propofol does not effectively inhibit enflurane metabolism performed by the isoniazid-inducible cytochrome P450IIE1 but effectively impairs activities of the phenobarbital-inducible cytochrome P450 isozymes. (Anesth Analg 1993;76:817–21)