Interaction entre Fosamprénavir et Rifapentine

Initiation of medications that inhibit or induce CYP3A may increase or decrease concentrations of fosamprenavir calcium/ritonavir, respectively.

Coadministration of fosamprenavir calcium with drugs that induce CYP3A4 may decrease amprenavir (active metabolite) concentrations leading to potential loss of virologic activity.

Coadministration of fosamprenavir calcium and drugs that induce CYP3A4, such as rifampin, may decrease amprenavir concentrations and reduce its therapeutic effect.

Data also suggest that amprenavir induces CYP3A4.

Ritonavir also appears to induce CYP3A, CYP1A2, CYP2C9, CYP2C19, and CYP2B6, as well as other enzymes, including glucuronosyl transferase.

Concomitant use of rifapentine with other drugs metabolized by these enzymes, such as protease inhibitors, certain reverse transcriptase inhibitors, and hormonal contraception may cause a significant decrease in plasma concentrations and loss of therapeutic effect [see Drug Interactions (7.1 , 7.2 , 7.3 , 7.4) and Clinical Pharmacology (12.3) ] .

Concomitant use of PRIFTIN with other drugs metabolized by these enzymes, such as protease inhibitors and certain reverse transcriptase inhibitors, may cause a significant decrease in plasma concentrations and loss of therapeutic effect of the protease inhibitor or reverse transcriptase inhibitor [see Warnings and Precautions (5.6) and Clinical Pharmacology (12.3)…

Fixed-Dose Combination of Efavirenz, Emtricitabine, and Tenofovir Once-weekly coadministration of 900 mg PRIFTIN with the antiretroviral fixed-dose combination of efavirenz 600 mg, emtricitabine 200 mg and tenofovir disoproxil fumarate 300 mg in HIV-infected patients did not result in any substantial change in steady state exposures of efavirenz, emtricitabine,…

Protease Inhibitors and Reverse Transcriptase Inhibitors.

Protease Inhibitors and Reverse Transcriptase Inhibitors Rifapentine is an inducer of CYP450 enzymes.