Drug Interaction Report

Using tenofovir together with darunavir may increase the plasma concentrations of both medicines. You may need a special test or more frequent monitoring by your doctor to safely use both medications. Contact your doctor if your condition changes or you experience increased side effects such as kidney problems. 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.

Using cobicistat together with tenofovir can increase the effects of tenofovir, which can cause new or worse kidney problems. You may need a dose adjustment or more frequent monitoring by your doctor to safely use both medications. Contact your doctor if your condition changes or you experience increased side effects. 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.

MONITOR: Coadministration with maribavir may increase the plasma concentrations of drugs that are substrates of the P-glycoprotein (P-gp) and/or breast cancer resistance protein (BCRP) efflux transporters, both of which have been shown to be inhibited in vitro by maribavir at clinically relevant concentrations. Inhibition of transporter-mediated efflux in the intestine and possibly other organs such as the liver and kidney can increase the systemic bioavailability and decrease the clearance of affected substrates. When a single 0.5 mg dose of digoxin, a sensitive P-gp substrate, was coadministered with maribavir 400 mg twice daily in 18 study subjects, mean digoxin peak plasma concentration (Cmax) and systemic exposure (AUC) increased by 25% and 21%, respectively, compared to digoxin administered alone. There are no clinical data regarding the use of maribavir with BCRP substrates, but increases in plasma concentrations of sensitive substrates such as rosuvastatin are expected according to the prescribing information.

MANAGEMENT: Caution is advised when maribavir is prescribed with drugs that are P-gp and/or BCRP substrates, particularly sensitive substrates or those with a narrow therapeutic range. Clinical and laboratory monitoring as well as dosage adjustments may be appropriate for some drugs whenever maribavir is added to or withdrawn from therapy. The prescribing information for concomitant medications should be consulted to assess the benefits versus risks of coadministration of P-gp/BCRP inhibitors and for any dosage adjustments that may be required.

Cobicistat is a medication used to boost the effects of some medications that treat HIV infection. However, using cobicistat together with other HIV medications, such as emtricitabine, may alter the blood levels and effects of both medications. Using emtricitabine with cobicistat may reduce or increase blood levels of cobicistat. Reduced blood levels of cobicistat may make cobicistat less effective and may cause overall HIV treatment to be less effective. Cobicistat may increase blood levels of emtricitabine which may increase the risk of side effects. Talk to your doctor or pharmacist if you have any questions on how to use these medications properly. Your doctor may be able to prescribe alternatives that do not interact, or you may need a dose adjustment or more frequent monitoring to safely use both medications. Contact your doctor if your condition changes or you experience increased side effects. 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.

Information for this minor interaction is available on the professional version.

Information for this minor interaction is available on the professional version.

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).

Information for this minor interaction is available on the professional version.