Interactions between zidovudine and Aptivus (tipranavir)
zidovudine and tipranavir (Moderate Drug-Drug)
MONITOR: Coadministration with tipranavir in combination with low-dose ritonavir may decrease the plasma concentrations of zidovudine. The mechanism of interaction is unknown. In 102 HIV-positive subjects, three different regimens of tipranavir/ritonavir (250 mg/200 mg; 750 mg/100 mg; and 1250 mg/100 mg twice a day for 21 days) decreased the mean peak plasma concentration (Cmax) and area under the plasma concentration-time curve (AUC) of steady-state zidovudine (300 mg twice a day) by approximately 50% and 35%, respectively, compared to administration of zidovudine without tipranavir/ritonavir. In 54 healthy volunteers, tipranavir/ritonavir (500 mg/100 mg and 750 mg/200 mg twice a day for 12 days) reduced the Cmax and AUC of zidovudine (300 mg single dose) by approximately 60% and 40%, respectively. The clinical significance of these changes is unknown. Zidovudine had negligible effects on the pharmacokinetics of tipranavir.
MANAGEMENT: Antiretroviral response should be monitored closely when tipranavir/ritonavir is used in combination with zidovudine. Currently, there are no dosage adjustment recommendations available for zidovudine when prescribed with tipranavir/ritonavir.
