Drug Interactions between dextromethorphan / quinidine and riociguat

Do not consume grapefruit or grapefruit juice during treatment with quiNIDine unless specifically directed otherwise by your doctor. Grapefruit and grapefruit juice can interact with quiNIDine and increase the levels of quiNIDine in your body. If you are already consuming grapefruit products, do not increase or decrease the amount of these products in your diet without first talking to your doctor.

Alcohol can increase the nervous system side effects of dextromethorphan such as dizziness, drowsiness, and difficulty concentrating. Some people may also experience impairment in thinking and judgment. You should avoid or limit the use of alcohol while being treated with dextromethorphan. Do not use more than the recommended dose of dextromethorphan, and avoid activities requiring mental alertness such as driving or operating hazardous machinery until you know how the medication affects you. Talk to your doctor or pharmacist if you have any questions or concerns.

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.