Liverpool HIV Interactions

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Do Not Coadminister

Darunavir/Cobicistat/ Emtricitabine/Tenofovir alafenamide (DRV/c/FTC/TAF)

Carbamazepine

Quality of Evidence: Moderate

Summary:

Coadministration with Symtuz has not been assessed in pharmacokinetic studies and is contraindicated. Coadministration could potentially increase carbamazepine concentrations and significantly reduce darunavir/cobicistat and tenofovir alafenamide plasma concentrations which may result in loss of therapeutic effect and development of resistance. Coadministration of carbamazepine (titrated from 100 mg to 300 mg twice a day) with emtricitabine/tenofovir alafenamide (200/25 mg once daily) decreased tenofovir alafenamide AUC and Cmax by 55% and 57%, respectively. Emtricitabine does not interact with this metabolic pathway. Limited data from a small number of patients showed TDM evaluations for carbamazepine and oxcarbazepine were within the therapeutic ranges and TDM results of darunavir were comparable with control values.

Description:

Coadministration is contraindicated due to the potential for loss of therapeutic effect. Based on theoretical considerations carbamazepine is expected to decrease darunavir and/or cobicistat and/or tenofovir alafenamide plasma concentrations (CYP3A and/or P-gp induction).

Symtuza Summary of Product Characteristics, Janssen-Cilag Ltd, June 2023.

Co-administration is contraindicated due to potential for loss of therapeutic effect and development of resistance. Co-administration is expected to decrease cobicistat, darunavir and tenofovir alafenamide concentrations.

Symtuza US Prescribing Information, Janssen Products, March 2023.

The drug-drug interactions between antiretrovirals and carbamazepine or oxcarbazepine were evaluated in a clinical setting using therapeutic drug monitoring (TDM) trough concentrations collected from HIV+ patients treated concomitantly with carbamazepine or oxcarbazepine and antiretrovirals for at least 3 months. HIV-infected patients not concomitantly treated with antiepileptic drugs and who underwent TDM for antiretrovirals in the previous 2 years were considered as controls. Eleven HIV-positive patients prescribed carbamazepine (n=7) or oxcarbazepine (n=4) were identified. All the TDM evaluations for carbamazepine and oxcarbazepine were within the therapeutic ranges. TDM results of darunavir measured in these patients were comparable with values usually measured in the control group.

Drug-drug interactions between antiretrovirals and carbamazepine/oxcarbazepine: a real-life investigation. Cattaneo D, Baldelli S, Cozzi V, et al. Ther Drug Monit. 2020;42(2):330-334.