How the interaction occurs:
In addition to treating seizures, topiramate also inhibits the carbonic anhydrase enzyme. When this enzyme is inhibited, your kidneys do not remove as much citrate as they normally do and the acidity of your urine is decreased. These conditions can increase the risk of a kidney stone forming.
What might happen:
If you use these medicines together, you may get a kidney stone.
What you should do about this interaction:
Let your healthcare professionals (e.g. doctor or pharmacist) know that you are taking these medicines together. Also tell your doctor if you are a special diet for weight loss or epilepsy. Some of these diets may also increase your risk of a kidney stone. Your doctor may want to change one of your medicines. You may need to drink more water while taking these medicines together. If you develop any symptoms of a kidney stone (blood in your urine, a burning sensation when urinating, or pain in the lower back), contact your doctor.Your healthcare professionals 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.Reference:1.Topamax (topiramate) US prescribing information. Janssen Pharmaceuticals, Inc. October, 2012.