Tolterodine (>1 mg or >2 mg ER)/Selected CYP3A4 Inhibitors
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:
Cyclosporine, erythromycin, miconazole, and vinblastine may prevent your body from processing tolterodine correctly.
What might happen:
The levels of tolterodine in your blood may increase. You may notice an increase in side effects from your tolterodine, such as blurred vision, dizziness, drowsiness, dry mouth, upset stomach, headache, dry eyes, or constipation.
What you should do about this interaction:
If you notice an increase in any side effects from your tolterodine, contact your healthcare professional (e.g. doctor or pharmacist). Your doctor may want to decrease the dose of your tolterodine.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.
1.Detrol (tolterodine tartrate) US prescribing information. Pfizer Inc. August, 2012.
2.Detrol LA (tolterodine tartrate) US prescribing information. Pfizer Inc. August, 2012.
3.Brynne N, Forslund C, Hallen B, Gustafsson LL, Bertilsson L. Ketoconazole inhibits the metabolism of tolterodine in subjects with deficient CYP2D6 activity. Br J Clin Pharmacol 1999 Oct;48(4):564-72.