Severe. These medicines may interact and cause very harmful effects and are usually not taken together. Contact your healthcare professional (e.g. doctor or pharmacist) for more information.
How the interaction occurs:
Your diuretic (or "water-pill") lowers the amount of potassium in your blood. If your potassium levels are too low, cisapride may have harmful effects on your heart.
What might happen:
You may experience an irregular heartbeat that may be life threatening.
What you should do about this interaction:
Contact your healthcare professionals (e.g. doctor or pharmacist) as soon as possible about taking these two medicines together. You may need to have your potassium level checked. Your doctor may want you to take a potassium supplement or your medicine may need to be changed. They may already be aware of this interaction and may be monitoring you for it. Do not start, stop, or change the dosage of any medicine before checking with them first.
1.Prepulsid (cisapride) US prescribing information. Janssen Pharmaceutica Products, L.P. January, 2000.
2.Drew BJ, Ackerman MJ, Funk M, Gibler WB, Kligfield P, Menon V, Philippides GJ, Roden DM, Zareba W. Prevention of torsade de pointes in hospital settings: a scientific statement from the American Heart Association and the American College of Cardiology Foundation. J Am Coll Cardiol 2010 Mar 2;55(9):934-47.