Effect of ritonavir/saquinavir on stereoselective pharmacokinetics of methadone: results of AIDS Clinical Trials Group (ACTG) 401.
J Acquir Immune Defic Syndr
; 27(2): 153-60, 2001 Jun 01.
Article
in En
| MEDLINE
| ID: mdl-11404537
ABSTRACT
UNLABELLED The effect of ritonavir 400 mg/saquinavir 400 mg twice daily on the stereoselective pharmacokinetics of methadone was examined in 12 HIV-infected, methadone-using study subjects. DESIGN:
A 24-hour methadone pharmacokinetic study was performed before antiretroviral therapy was begun and after 15 days of therapy. Methadone concentration was measured by a chiral plasma assay because the drug is administered as a racemic mixture of R- and S-methadone, but only the R-isomer is active. Both changes in plasma protein binding and changes in objective and subjective opioid effect were monitored.RESULTS:
Ritonavir/saquinavir administration was associated with 40% decrease in total S-methadone AUC0-24hr and 32% decrease in R-methadone area under the curve (AUC)0-24hr, and both changes were statistically significant (p =.001 for both). When AUC was corrected for the changes in protein binding induced by ritonavir/saquinavir, R-methadone free AUC0-24hr decreased 19.6% whereas the S-methadone decreased 24.6%, neither of these changes was statistically significant (p =.129 and p =.0537, respectively). This change in methadone exposure was not associated with any evidence of withdrawal from narcotics and no modification of methadone dose was required.CONCLUSIONS:
Our data indicate that ritonavir/saquinavir administration is associated with induction of metabolism of methadone but this is greater for the inactive S-methadone. However, approximately 37% of the decrease in the total R-methadone exposure can be explained by protein binding displacement. Ritonavir/saquinavir can be used in HIV-infected people taking methadone without routine dose adjustments.
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Collection:
01-internacional
Database:
MEDLINE
Main subject:
HIV Protease Inhibitors
/
Ritonavir
/
Saquinavir
/
Methadone
/
Narcotics
Type of study:
Prognostic_studies
Limits:
Adult
/
Female
/
Humans
/
Male
/
Middle aged
Language:
En
Journal:
J Acquir Immune Defic Syndr
Journal subject:
SINDROME DA IMUNODEFICIENCIA ADQUIRIDA (AIDS)
Year:
2001
Document type:
Article
Affiliation country:
United States