title: Amprenavir and efavirenz pharmacokinetics before and after the addition of nelfinavir, indinavir, ritonavir, or saquinavir in seronegative individuals.
abstract: Adult AIDS Clinical Trials Group 5043 examined pharmacokinetic (PK) interactions between amprenavir (APV) and efavirenz (EFV) both by themselves and when nelfinavir (NFV), indinavir (IDV), ritonavir (RTV), or saquinavir (SQV) is added. A PK study was conducted after the administration of single doses of APV (day 0). Subjects (n = 56) received 600 mg of EFV every 24 h (q24h) for 10 days and restarted APV with EFV for days 11 to 13 with a PK study on day 14. A second protease inhibitor (PI) (NFV, 1,250 mg, q12h; IDV, 1,200 mg, q12h; RTV, 100 mg, q12h; or SQV, 1,600 mg, q12h) was added to APV and EFV on day 15, and a PK study was conducted on day 21. Controls continued APV and EFV without a second PI. Among subjects, the APV areas under the curve (AUCs) on days 0, 14, and 21 were compared using the Wilcoxon signed-rank test. Ninety-percent confidence intervals around the geometric mean ratios (GMR) were calculated. APV AUCs were 46% to 61% lower (median percentage of AUC) with EFV (day 14 versus day 0; P values of <0.05). In the NFV, IDV, and RTV groups, day 21 APV AUCs with EFV were higher than AUCs for EFV alone. Ninety-percent confidence intervals around the GMR were 3.5 to 5.3 for NFV (P < 0.001), 2.8 to 4.5 for IDV (P < 0.001), and 7.8 to 11.5 for RTV (P = 0.004). Saquinavir modestly increased the APV AUCs (GMR, 1.0 to 1.4; P = 0.106). Control group AUCs were lower on day 21 compared to those on day 14 (GMR, 0.7 to 1.0; P = 0.042). African-American non-Hispanics had higher day 14 efavirenz AUCs than white non-Hispanics. We conclude that EFV lowered APV AUCs, but nelfinavir, indinavir, or ritonavir compensated for EFV induction.
authors.affiliation: Adult ACTG Pharmacology Support Laboratory, Pharmacotherapy Research Center, Department of Pharmacy Practice, School of Pharmacy and Pharmaceutical Sciences, 317 Hochstetter Hall, University at Buffalo, Amherst, NY 14260, USA. emorse@buffalo.edu
authors.forename: Gene D
authors.initials: GD
authors.lastname: Morse
authors.forename: Susan
authors.initials: S
authors.lastname: Rosenkranz
authors.forename: Michael F
authors.initials: MF
authors.lastname: Para
authors.forename: Yoninah
authors.initials: Y
authors.lastname: Segal
authors.forename: Robin
authors.initials: R
authors.lastname: Difrancesco
authors.forename: Elizabeth
authors.initials: E
authors.lastname: Adams
authors.forename: Barbara
authors.initials: B
authors.lastname: Brizz
authors.forename: Kevin E
authors.initials: KE
authors.lastname: Yarasheski
authors.forename: Richard C
authors.initials: RC
authors.lastname: Reichman
mesh_terms: D000293:Adolescent; D000328:Adult; D000480:Alkynes; D019380:Anti-HIV Agents / Q000008:administration & dosage / Q000009:adverse effects / Q000493:pharmacokinetics*; D019540:Area Under Curve; D048588:Benzoxazines; D002219:Carbamates; D003521:Cyclopropanes; D004347:Drug Interactions; D004359:Drug Therapy, Combination; D005260:Female; D005663:Furans; D017320:HIV Protease Inhibitors / Q000008:administration & dosage* / Q000009:adverse effects; D018023:HIV Seronegativity; D006801:Humans; D008297:Male; D008875:Middle Aged; D010078:Oxazines / Q000008:administration & dosage / Q000009:adverse effects / Q000493:pharmacokinetics*; D018894:Reverse Transcriptase Inhibitors / Q000008:administration & dosage / Q000009:adverse effects / Q000493:pharmacokinetics*; D013449:Sulfonamides / Q000008:administration & dosage / Q000009:adverse effects / Q000493:pharmacokinetics*
chemical_list: D000480:Alkynes; D019380:Anti-HIV Agents; D048588:Benzoxazines; D002219:Carbamates; D003521:Cyclopropanes; D005663:Furans; D017320:HIV Protease Inhibitors; D010078:Oxazines; D018894:Reverse Transcriptase Inhibitors; D013449:Sulfonamides; C095108:amprenavir; C098320:efavirenz