Amprenavir and ritonavir plasma concentrations in HIV-infected patients treated with fosamprenavir/ritonavir with various degrees of liver impairment.
OBJECTIVE
The purpose of this study was to evaluate the steady-state pharmacokinetics of amprenavir and ritonavir in HIV-infected patients with different degrees of hepatic impairment.


METHODS
HIV-positive patients receiving fosamprenavir/ritonavir (700/100 mg twice daily) were included. Patients were classified into three groups: (i) chronic hepatitis; (ii) liver cirrhosis; (iii) normal liver function. Serial blood samples for steady-state amprenavir and ritonavir pharmacokinetics (>14 days on treatment) were collected in the fasting state before the morning dose (C(trough)) and then 1, 2, 3, 4, 6, 8, 10 and 12 h after drug intake. Amprenavir and ritonavir plasma concentrations were determined by HPLC.


RESULTS
Twenty-one HIV-infected patients were included. Seven had chronic hepatitis, eight had liver cirrhosis and six patients were in the control group. Amprenavir AUC(0-12), AUC(0-infinity), C(max) and C(ss) were increased by 50% to 60% in the cirrhotic group when compared with controls, whereas CL/F was decreased by 40%. Patients with chronic hepatitis showed a significant increase in AUC(0-12), C(max) and C(ss) values when compared with controls. Ritonavir pharmacokinetics was different only in cirrhotic patients when compared with controls. Liver function parameters at weeks 4, 12 and 24 were not different from baseline in any of the groups. Overall, a significant correlation between amprenavir AUC(0-12) and total bilirubin values on the day of pharmacokinetic analysis was found (r = 0.64, P = 0.003).


CONCLUSIONS
On the basis of these data and also of data available in the literature, it seems reasonable to adapt the dose of fosamprenavir and/or ritonavir exclusively in the presence of adverse events, possibly related to protease inhibitors (i.e. liver toxicity), in subjects with high drug plasma levels. Therapeutic drug monitoring is advised in the management of these patients.
Infectious Disease Department, San Raffaele Scientific Institute and Università Vita-Salute San Raffaele, Via Stamina d'Ancona 20, 20122 Milan, Italy. elena.seminari@hsr.it
Elena
E
Seminari
Anna
A
De Bona
Gianluca
G
Gentilini
Laura
L
Galli
Giulia
G
Schira
Nicola
N
Gianotti
Caterina
C
Uberti-Foppa
Armando
A
Soldarini
Fernanda
F
Dorigatti
Adriano
A
Lazzarin
Antonella
A
Castagna
D000328:Adult; D019380:Anti-HIV Agents / Q000097:blood / Q000493:pharmacokinetics* / Q000627:therapeutic use; D019540:Area Under Curve; D001288:Attention; D001663:Bilirubin / Q000097:blood; D002219:Carbamates / Q000008:administration & dosage / Q000097:blood / Q000493:pharmacokinetics* / Q000627:therapeutic use*; D002851:Chromatography, High Pressure Liquid; D005260:Female; D005663:Furans; D015658:HIV Infections / Q000150:complications* / Q000188:drug therapy*; D006801:Humans; D008107:Liver Diseases / Q000150:complications*; D008297:Male; D008875:Middle Aged; D010755:Organophosphates / Q000008:administration & dosage / Q000627:therapeutic use*; D010949:Plasma / Q000737:chemistry*; D019438:Ritonavir / Q000008:administration & dosage / Q000097:blood / Q000493:pharmacokinetics* / Q000627:therapeutic use; D013449:Sulfonamides / Q000008:administration & dosage / Q000097:blood / Q000493:pharmacokinetics* / Q000627:therapeutic use*; D013997:Time Factors
D019380:Anti-HIV Agents; D002219:Carbamates; D005663:Furans; D010755:Organophosphates; D013449:Sulfonamides; C095108:amprenavir; D019438:Ritonavir; D001663:Bilirubin; C426859:fosamprenavir