Drug Interactions between Detrol and toremifene

Consumer information for this interaction is not currently available.

GENERALLY AVOID: Toremifene has the potential to prolong the QT interval of the electrocardiogram in some patients. Theoretically, coadministration with other agents that can prolong the QT interval may result in additive effects and increased risk of ventricular arrhythmias including torsade de pointes and sudden death. The effect on the QT interval is dose- and concentration-dependent. In a placebo-controlled, parallel-design clinical trial, the mean QTc interval prolongation was 21 to 26 ms with 80 mg toremifene, and the 20 mg dose also affected the QTc interval. Abnormal new U waves were observed in 4.3% of subjects with the 80 mg dose. There are no data available for the therapeutic 60 mg dose. In general, the risk of an individual agent or a combination of agents causing ventricular arrhythmia in association with QT prolongation is largely unpredictable but may be increased by certain underlying risk factors such as congenital long QT syndrome, cardiac disease, and electrolyte disturbances (e.g., hypokalemia, hypomagnesemia). In addition, women and elderly patients may be more susceptible to the QT prolonging effects of drugs.

MANAGEMENT: Coadministration of toremifene with other drugs that can prolong the QT interval should generally be avoided. If treatment with other QT-prolonging drugs is required, interruption of toremifene therapy should be considered. Caution and clinical monitoring are recommended if concomitant use is unavoidable. In patients at increased risk, electrocardiograms (ECGs) are recommended at baseline and as clinically indicated. Patients should be advised to seek prompt medical attention if they experience symptoms that could indicate the occurrence of torsade de pointes such as dizziness, lightheadedness, fainting, palpitation, irregular heart rhythm, shortness of breath, or syncope.