Drug Interaction Report

Ask your doctor before using carBAMazepine together with darunavir. Using these medications together may cause darunavir to be less effective. If your doctor prescribes these medications together, you may need a dose adjustment or special tests to safely take 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.

Consumer information for this interaction is not currently available.

CONTRAINDICATED: Coadministration of cobicistat with a drug that is both a substrate as well as a potent inducer of CYP450 3A4 may result in significantly decreased plasma concentrations of cobicistat and significantly increased concentrations of the other drug. Cobicistat is a substrate and a potent inhibitor of CYP450 3A4. In a study of 12 healthy volunteers, coadministration of the potent CYP450 3A4 inducer carbamazepine (200 mg twice daily) with cobicistat-elvitegravir (150 mg-150 mg once a day) reduced the cobicistat systemic exposure (AUC) and peak plasma concentration (Cmax) by 84% and 72%, respectively, and the elvitegravir AUC and Cmax by 69% and 45%, respectively. In addition, the AUC and Cmax of carbamazepine increased by 43% and 40%, respectively, due to inhibition of the CYP450 3A4-mediated metabolism by cobicistat.

MANAGEMENT: Given the risk of reduced viral susceptibility and resistance development associated with subtherapeutic drug levels along with the risk of serious and/or life-threatening adverse effects associated with elevated plasma levels, the concomitant use of antiretroviral regimens containing cobicistat with potent CYP450 3A4 inducers that are also sensitive CYP450 3A4 substrates is considered contraindicated.

You should preferably avoid the regular consumption of grapefruits and grapefruit juice while taking carBAMazepine. This can cause carBAMazepine levels to increase. You should report signs of carBAMazepine side effects such as nausea, visual disturbances, dizziness, or muscle weakness to your doctor. You should avoid or limit the use of alcohol while being treated with carBAMazepine. Alcohol can increase the nervous system side effects of carBAMazepine such as dizziness, drowsiness, and difficulty concentrating. Some people may also experience impairment in thinking and judgment. Talk to your doctor or pharmacist if you have any questions or concerns.

Food can enhance the levels of darunavir in your body. Take darunavir with food. The type of food does not matter. This will make it easier for your body to absorb the medication. Swallow the whole tablets with a drink such as water or milk. Do not chew the tablets. Darunavir must be always be taken together at the same time as another medication called ritonavir (Norvir).