title: Cytochrome P450 induction by rifampicin in healthy subjects: determination using the Karolinska cocktail and the endogenous CYP3A4 marker 4beta-hydroxycholesterol.
abstract: The Karolinska cocktail, comprising caffeine, losartan, omeprazole, and quinine, was given before and after administration of rifampicin (20, 100, or 500 mg daily) to measure induction of cytochrome P450 (P450) enzymes. Rifampicin was given for 14 days to eight healthy subjects (all of whom possessed at least one wild-type CYP2C9 and one wild-type CYP2C19 gene) in each dose group. 4beta-hydroxycholesterol was assessed as an endogenous marker of CYP3A4 induction. A fourfold induction of CYP3A4 was seen at the highest dose by both quinine:3'-hydroxyquinine and 4beta-hydroxycholesterol measurements (P < 0.001). CYP3A4 was also induced at the two lower doses of rifampicin when measured by these two markers (P < 0.01 or P < 0.001). CYP1A2, CYP2C9, and CYP2C19 were induced after 500 mg rifampicin daily (1.2-fold, P < 0.05; 1.4-fold, P < 0.05; and 4.2-fold, P < 0.01, respectively). In conclusion, we have shown that the Karolinska cocktail and 4beta-hydroxycholesterol can be used for an initial screening of the induction properties of a drug candidate.
authors.affiliation: Division of Clinical Pharmacology, Department of Laboratory Medicine, Karolinska Institutet, Karolinska University Hospital, Huddinge, Sweden.
authors.forename: K P
authors.initials: KP
authors.lastname: Kanebratt
authors.forename: U
authors.initials: U
authors.lastname: Diczfalusy
authors.forename: T
authors.initials: T
authors.lastname: Bäckström
authors.forename: E
authors.initials: E
authors.lastname: Sparve
authors.forename: E
authors.initials: E
authors.lastname: Bredberg
authors.forename: Y
authors.initials: Y
authors.lastname: Böttiger
authors.forename: T B
authors.initials: TB
authors.lastname: Andersson
authors.forename: L
authors.initials: L
authors.lastname: Bertilsson
mesh_terms: D000328:Adult; D000897:Anti-Ulcer Agents / Q000008:administration & dosage / Q000097:blood / Q000494:pharmacology; D000904:Antibiotics, Antitubercular / Q000494:pharmacology*; D000959:Antihypertensive Agents / Q000008:administration & dosage / Q000494:pharmacology / Q000652:urine; D000962:Antimalarials / Q000008:administration & dosage / Q000378:metabolism / Q000494:pharmacology; D002110:Caffeine / Q000008:administration & dosage / Q000097:blood / Q000494:pharmacology; D000697:Central Nervous System Stimulants / Q000008:administration & dosage / Q000097:blood / Q000494:pharmacology; D003577:Cytochrome P-450 Enzyme System / Q000096:biosynthesis* / Q000502:physiology; D004338:Drug Combinations; D004790:Enzyme Induction / Q000187:drug effects; D005260:Female; D006801:Humans; D006888:Hydroxycholesterols / Q000097:blood*; D019808:Losartan / Q000008:administration & dosage / Q000494:pharmacology / Q000652:urine; D008297:Male; D008875:Middle Aged; D009853:Omeprazole / Q000008:administration & dosage / Q000097:blood / Q000494:pharmacology; D011803:Quinine / Q000008:administration & dosage / Q000378:metabolism / Q000494:pharmacology; D012293:Rifampin / Q000494:pharmacology*
chemical_list: D000897:Anti-Ulcer Agents; D000904:Antibiotics, Antitubercular; D000959:Antihypertensive Agents; D000962:Antimalarials; D000697:Central Nervous System Stimulants; D004338:Drug Combinations; D006888:Hydroxycholesterols; C099828:cholest-5-ene-3,4-diol; D002110:Caffeine; D003577:Cytochrome P-450 Enzyme System; D011803:Quinine; D019808:Losartan; D009853:Omeprazole; D012293:Rifampin