Date of report 04 Jul 2019
Reported case interaction between
Dolutegravir and Oxcarbazepine
Dolutegravir and Oxcarbazepine
Drugs suspected to be involved in the DDI
Complete list of drugs taken by the patient
Oxcarbazepine (600 mg qd), quetiapine (300 mg qd), olanzapine (15 mg qd), mirtazapine (15 mg qd)
Clinical case description
41-year-old patient diagnosed with HIV infection in 2005. On cART with dolutegravir/3TC/ABC since 2016. No prior failures. Psycotic disorder on treatment with quetiapine (300 mg qd), olanzapine (15 mg qd), mirtazapine (15 mg qd) and, since November 2017, with oxcarbazepine (600 mg qd). Despite potential decrease in dolutegravir concentrations due to induction of UGT1A1 and CYP3A by oxcarbazepine, the patient has maintained HIV viral load <50 copies/mL until last follow up (June 2019), even when he is receiving dolutegravir 50 mg qd (the European SPC suggests that dolutegravir be dosed at 50 mg twice daily in this context).
Clinical Outcome
Editorial Comment
Coadministration of dolutegravir with oxcarbazepine, phenytoin or phenobarbital has not been studied but, based on results of coadministration with carbamazepine, is expected to decrease dolutegravir exposure due to induction of UGT1A1 and CYP3A. The US Prescribing Information advises to avoid coadministration due to insufficient data to make dosing recommendations. However, the European SPC suggests that dolutegravir be dosed at 50 mg twice daily, but recommends that alternative combinations should be used where possible in INSTI-resistant patients.
University of Liverpool Recommendation
Potential interaction - may require close monitoring, alteration of drug dosage or timing of administration