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Pharmacokinetic interaction between amprenavir and delavirdine: Evidence of induced clearance by amprenavir
Author(s) -
Tran Jonathan Q.,
Petersen Carolyn,
Garrett May,
Hee Brian,
Kerr Bradley M.
Publication year - 2002
Publication title -
clinical pharmacology and therapeutics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.941
H-Index - 188
eISSN - 1532-6535
pISSN - 0009-9236
DOI - 10.1067/mcp.2002.128868
Subject(s) - amprenavir , pharmacokinetics , medicine , pharmacology , chemistry , biochemistry , enzyme , hiv 1 protease , protease
Objective Our objective was to determine the pharmacokinetic interaction between amprenavir and delavirdine. Methods Healthy volunteers participated in 2 open‐label, 3‐period, longitudinal studies. In the first study, 12 volunteers received a single dose of amprenavir, 1200 mg, alone and then again after 7 days of delavirdine, 600 mg twice daily. In the second study, another 12 subjects received amprenavir, 1200 mg twice daily, alone for 7 days. After a 7‐day washout period, subjects received delavirdine, 600 mg twice daily, alone for 7 days followed by a combination with amprenavir, 600 mg twice daily, for another 7 days. Amprenavir and delavirdine pharmacokinetics when given alone and in combination were compared. Results All 12 subjects completed the first study, and 11 subjects completed the second study. Delavirdine significantly increased the area under the curve (AUC) of single‐dose amprenavir by 4‐fold ( P = .0001). Amprenavir, 600 mg twice daily, with delavirdine produced higher levels of amprenavir AUC, minimum concentration (C min ), and maximum concentration (C max ), by 30%, 90%, and 18%, respectively, than those of amprenavir, 1200 mg twice daily, alone ( P < .05). In contrast, amprenavir decreased delavirdine AUC, C min , and C max by 50%, 70%, and 30%, respectively ( P < .005). Conclusions Because of the inhibitory effect of delavirdine on the cytochrome P450 3A4‐mediated metabolism of amprenavir, the combination of a reduced dose of amprenavir, 600 mg twice daily, with delavirdine resulted in a higher amprenavir exposure than the standard dose of amprenavir, 1200 mg twice daily. However, amprenavir induced the clearance of delavirdine, resulting in a reduction in delavirdine exposure. Further clinical studies are needed to determine the appropriate dosing regimens for delavirdine and amprenavir during coadministration. Clinical Pharmacology & Therapeutics (2002) 72 , 615–626; doi: 10.1067/mcp.2002.128868