Drug Interactions between calcium carbonate / risedronate and riociguat

Calcium absorption may be increased by taking it with food. However, foods high in oxalic acid (spinach or rhubarb), or phytic acid (bran and whole grains) may decrease calcium absorption. Calcium may be taken with food to increase absorption. Consider spacing calcium administration for at least 2 hours before or after consuming foods high in oxalic acid or phytic acid. Talk to your doctor if you have any questions or concerns. 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 reduce the absorption of risedronate, which may lead to lower blood levels of the medication and possibly reduced effectiveness. You should take risedronate first thing in the morning, at least 30 minutes before you eat or drink anything or take any other medication. Take each dose with a full glass (6 to 8 ounces) of water, and use only plain water (not mineral or vitamin water). Do not take risedronate if you cannot sit upright or stand for at least 30 minutes. Because risedronate can cause irritation and ulcer in the stomach or esophagus (the tube that connects your mouth and stomach), you will need to stay upright for at least 30 minutes after taking this medication. Talk to your doctor or pharmacist if you have questions on how to take this or other medications you are prescribed. 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.

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.