Before taking fesoterodine,
tell your doctor and pharmacist if you are allergic to fesoterodine, tolterodine (Detrol, Detrol LA), any other medications, or any of the ingredients in fesoterodine tablets. Ask your pharmacist for a list of the ingredients.
tell your doctor and pharmacist what other prescription and nonprescription medications, vitamins, nutritional supplements, and herbal products you are taking or plan to take. Be sure to mention any of the following: antihistamines; certain antifungals such as itraconazole (Sporanox) and ketoconazole (Nizoral); clarithromycin (Biaxin); diltiazem (Cardizem, Cartia XT, Dilacor XR®, others); erythromycin (ERY-C, Ery-Tab); certain HIV protease inhibitors including indinavir (Crixivan), nelfinavir (Viracept), and ritonavir (Norvir); ipratropium (Atrovent); medications for irritable bowel disease, motion sickness, Parkinson's disease, or ulcers; other medications for urinary problems; and verapamil (Calan, Covera-HS, Isoptin SR, Verelan). Your doctor may need to change the doses of your medications or monitor you carefully for side effects.
tell your doctor if you are unable to empty your bladder, and if you have or have ever had slowed or delayed emptying of your stomach, or glaucoma (increased pressure in the eye that may lead to vision loss). Your doctor may tell you not to take fesoterodine.
tell your doctor if you have or have ever had a slow or weak urine stream, constipation, any conditions that affect your stomach or intestines, myasthenia gravis (a disease that causes severe muscle weakness), or liver or kidney disease.
tell your doctor if you are pregnant, plan to become pregnant, or are breast-feeding. If you become pregnant while taking fesoterodine, call your doctor.
you should know that fesoterodine may cause drowsiness and blurred vision. Do not drive a car or operate machinery until you know how this medication affects you.
ask your doctor about the safe use of alcoholic beverages while you are taking fesoterodine. Alcohol can add to the drowsiness caused by this medication.
you should know that fesoterodine may make it harder for your body to cool down when it gets very hot. Avoid exposure to extreme heat, and call your doctor or get emergency medical treatment if you have fever or other signs of heat stroke such as dizziness, upset stomach, headache, confusion, and fast pulse after you are exposed to heat.