Drug Interaction Report

Consumer information for this interaction is not currently available.

MONITOR: Coadministration with inhibitors of uridine diphosphate glucuronosyltransferase (UGT) 1A1 and/or 1A9 may increase the plasma concentrations of the riociguat metabolite M1, which is pharmacologically active and has 1/10th to 1/3rd the activity of the parent drug. UGT 1A1 and 1A9 are involved in the N-glucuronidation of metabolite M1 to the inactive metabolite M4. In vitro, the UGT 1A1 inhibitor atazanavir and the UGT 1A9 inhibitor niflumic acid considerably reduced the biotransformation of M1 to M4. The clinical significance of this interaction has not been established; however, increased levels of M1 may potentiate the risk of hypotension.

MANAGEMENT: Caution is advised when riociguat is prescribed with UGT 1A1 and/or 1A9 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.