Intelence and Rifabutin

In the database of official manuals used in the service creation an interaction registered by statistical results of studies was found, which can either lead to negative consequences for the patient health or strengthen a mutual positive effect. A doctor should be consulted to address the issue of joint drug administration.

Ask your doctor before using rifabutin together with etravirine. Using rifabutin together with etravirine may decrease the effects of etravirine. Contact your doctor if your condition changes. If your doctor does prescribe these medications together, you may need a dose adjustment or special test to safely use both medications. It is important to tell your doctor about all other medications you use, including vitamins and herbs. Do not stop using any medications without first talking to your doctor.

GENERALLY AVOID: (Only if etravirine is also coadministered with darunavir/ritonavir or saquinavir/ritonavir) Coadministration with rifabutin may decrease the plasma concentrations of etravirine. The mechanism is rifabutin induction of etravirine metabolism via CYP450 3A4. In 12 study subjects administered etravirine with rifabutin 300 mg once a day, etravirine peak plasma concentration (Cmax), systemic exposure (AUC) and trough plasma concentration (Cmin) decreased by approximately one-third each. These decreases are similar to those observed when etravirine is coadministered with darunavir/ritonavir or saquinavir/ritonavir. Because all subjects in Phase 3 trials of etravirine received darunavir/ritonavir as part of the background regimen and etravirine exposures from these trials were determined to be safe and effective, etravirine and rifabutin may be coadministered without any dosage adjustments. However, in the presence of darunavir/ritonavir or saquinavir/ritonavir, further reductions in the plasma concentrations of etravirine may occur.

Etravirine may also decrease the plasma concentrations of rifabutin and its active metabolite, 25-O-desacetylrifabutin. In the study, Cmax, AUC and Cmin of rifabutin decreased by 10%, 17% and 24%, respectively, while those of 25-O-desacetylrifabutin decreased by 15%, 17% and 22%, respectively. The clinical significance of these changes are unknown.

MANAGEMENT: Given the risk of reduced viral susceptibility and resistance development associated with subtherapeutic antiretroviral drug levels, rifabutin should not be prescribed if etravirine is coadministered with darunavir/ritonavir or saquinavir/ritonavir. Rifabutin 300 mg once a day is recommended if etravirine is not coadministered with a protease inhibitor/ritonavir combination.

Intelence

Generic Name: etravirine

Brand name: Intelence

Synonyms: n.a.

What is Intelence?

Rifabutin

Generic Name: rifabutin

Brand name: Mycobutin

Synonyms: n.a.

What is Rifabutin?