Drug Interaction Report

Consumer information for this interaction is not currently available.

MONITOR: Coadministration with potent inhibitors of CYP450 3A4 or moderate to potent inhibitors of P-glycoprotein (P-gp) or breast cancer resistant protein (BCRP) may increase the plasma concentrations of riociguat, which is partially metabolized by CYP450 3A and also a substrate of the P-gp and BCRP efflux transporters. Increased levels of riociguat may increase the risk for hypotension. When riociguat was administered with ketoconazole, a potent CYP450 3A4 inhibitor that also inhibits P-gp and BCRP, riociguat peak plasma concentration (Cmax) and systemic exposure (AUC) increased by approximately 1.5- and 2.5-fold, respectively. The Cmax and AUC of the active metabolite, M1, which has 1/10th to 1/3rd the pharmacologic activity of riociguat, were reduced by approximately 50% and 25%, respectively. Administration with the potent CYP450 3A4 inhibitor clarithromycin increased the AUC of riociguat by about 30%. The Cmax and AUC of M1 were not significantly altered (i.e., <20% increase).

MANAGEMENT: Caution is advised when riociguat is prescribed with potent CYP450 3A4 inhibitors or moderate to potent P-gp or BCRP inhibitors. Patients should be monitored for signs and symptoms of hypotension, and the dosage of riociguat adjusted if necessary.

Chemical substances present in cigarette smoke may reduce the blood levels of riociguat. This means that the medication may be less effective if you smoke during treatment. Let your doctor know if you are a smoker, or if you start smoking or stop smoking during treatment with riociguat, because the dosage may need to be adjusted. 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.

Food may affect the absorption and blood levels of riociguat. To avoid significant fluctuations in blood levels of the medication, riociguat should be taken about the same time each day consistently either with or without food.