This information is generalized and not intended as specific medical advice. Consult your healthcare professional before taking or discontinuing any drug, changing your diet or commencing any course of treatment.
Very important. A change in your diet, medicine, or dosage may be necessary. Promptly consult your doctor or pharmacist.
How the interaction occurs:
Fesoterodine is processed by enzymes in your intestine. Grapefruit and grapefruit juice contain compounds that slow down this process.
What might happen:
The amount of fesoterodine in your blood may increase and cause more side effects than expected. You may notice an increase in side effects, such as blurred vision, dizziness, drowsiness, dry mouth, upset stomach, headache, dry eyes, or constipation.
What you should do about this interaction:
While you are taking this medicine, you should avoid eating grapefruit or drink grapefruit juice. You may choose an alternative citrus beverage (such as orange juice).In the event that you are instructed by a healthcare professional (e.g., doctor, pharmacist, or dietitian) to eat grapefruit or drink grapefruit juice, you should immediately discuss with doctor the effects of grapefruit on the blood levels of this medicine.Your healthcare professionals may be aware of this interaction and may be monitoring you for it. Do not start, stop, or change your medicine or diet before checking with them first.
1.Toviaz (fesoterodine fumarate) US prescribing information. Pfizer August, 2012.
2.Malhotra B, Dickins M, Alvey C, Jumadilova Z, Li X, Duczynski G, Gandelman K. Effects of the Moderate CYP3A4 Inhibitor, Fluconazole, on the Pharmacokinetics of Fesoterodine in Healthy Subjects. Br J Clin Pharmacol 2011 May 5.
3.US Food and Drug Administration (FDA). Drug Development and Drug Interactions: Table of Substrates, Inhibitors and Inducers. Available at: http://www.fda.gov/Drugs/DevelopmentApprovalProcess/DevelopmentResources/D rugInteractionsLabeling/ucm093664.htm. Updated 08/05/2011.