title: Steady-state pharmacokinetics of amprenavir coadministered with ritonavir in human immunodeficiency virus type 1-infected patients.
abstract: The protease inhibitor (PI) ritonavir is used as a strong inhibitor of cytochrome P450 3A4, which boosts the activities of coadministered PIs, resulting in augmented plasma PI levels, simplification of the dosage regimen, and better efficacy against resistant viruses. The objectives of the present open-label, multiple-dose study were to determine the steady-state pharmacokinetics of amprenavir administered at 600 mg twice daily (BID) and ritonavir administered at 100 mg BID in human immunodeficiency virus type 1 (HIV-1)-infected adults treated with different antiretroviral combinations including or not including a nonnucleoside reverse transcriptase inhibitor (NNRTI). Nineteen patients completed the study. The steady-state mean minimum plasma amprenavir concentration (C(min,ss)) was 1.92 microg/ml for patients who received amprenavir and ritonavir without an NNRTI and 1.36 microg/ml for patients who received amprenavir and ritonavir plus efavirenz. For patients who received amprenavir-ritonavir without an NNRTI, the steady-state mean peak plasma amprenavir concentration (C(max,ss)) was 7.12 microg/ml, the area under the concentration-time curve from 0 to 10 h (AUC(0-10)) was 32.06 microg. h/ml, and the area under the concentration-time curve over a dosing interval (12 h) at steady-state (AUC(ss)) was 35.74 microg. h/ml. Decreases in the mean values of C(min,ss) (29%), C(max,ss) (42%), AUC(0-10) (42%), and AUC(ss) (40%) for amprenavir occurred when efavirenz was coadministered with amprenavir-ritonavir. No unexpected side effects were observed. As expected, coadministration of amprenavir with ritonavir resulted in an amprenavir C(min,ss) markedly higher than those previously reported for the marketed dose of amprenavir. When amprenavir-ritonavir was coadministered with efavirenz, amprenavir-ritonavir maintained a mean amprenavir C(min,ss) above the mean 50% inhibitory concentration of amprenavir previously determined for both wild-type HIV-1 isolates and HIV-1 strains isolated from PI-experienced patients. These data support the use of low-dose ritonavir to enhance the level of exposure to amprenavir and increase the efficacy of amprenavir.
authors.affiliation: Internal Medicine Department, Bicetre Hospital, Le Kremlin Bicetre, France.
authors.forename: Cecile
authors.initials: C
authors.lastname: Goujard
authors.forename: Isabelle
authors.initials: I
authors.lastname: Vincent
authors.forename: Jean-Luc
authors.initials: JL
authors.lastname: Meynard
authors.forename: Nathalie
authors.initials: N
authors.lastname: Choudet
authors.forename: Diane
authors.initials: D
authors.lastname: Bollens
authors.forename: Cyril
authors.initials: C
authors.lastname: Rousseau
authors.forename: Didier
authors.initials: D
authors.lastname: Demarles
authors.forename: Catherine
authors.initials: C
authors.lastname: Gillotin
authors.forename: Roselyne
authors.initials: R
authors.lastname: Bidault
authors.forename: Anne-Marie
authors.initials: AM
authors.lastname: Taburet
mesh_terms: D000328:Adult; D000480:Alkynes; D019540:Area Under Curve; D048588:Benzoxazines; D002219:Carbamates; D003521:Cyclopropanes; D004334:Drug Administration Schedule; D004359:Drug Therapy, Combination; D005260:Female; D005663:Furans; D015658:HIV Infections / Q000188:drug therapy* / Q000378:metabolism; D017320:HIV Protease Inhibitors / Q000097:blood / Q000493:pharmacokinetics* / Q000627:therapeutic use; D015497:HIV-1; D006207:Half-Life; D006801:Humans; D008297:Male; D010078:Oxazines / Q000008:administration & dosage / Q000627:therapeutic use; D019438:Ritonavir / Q000008:administration & dosage / Q000097:blood / Q000627:therapeutic use*; D013449:Sulfonamides / Q000008:administration & dosage / Q000097:blood / Q000493:pharmacokinetics*
chemical_list: D000480:Alkynes; D048588:Benzoxazines; D002219:Carbamates; D003521:Cyclopropanes; D005663:Furans; D017320:HIV Protease Inhibitors; D010078:Oxazines; D013449:Sulfonamides; C095108:amprenavir; C098320:efavirenz; D019438:Ritonavir