Treatment of overactive bladder: selective use of anticholinergic agents with low drug-drug interaction potential.

Overactive bladder (OAB) is highly prevalent in the older population and decreases quality of life. Current therapy consists primarily of anticholinergic drugs. Because older individuals typically take multiple medications, clinicians must pay special attention to potential drug-drug interactions that may cause adverse events or alter drug efficacy. The most clinically important drug-drug interactions occur during cytochrome P450 (CYP450) isoenzyme metabolism, resulting in altered metabolism of one or more of the coadministered agents. Of the drugs indicated for OAB, tolterodine, darifenacin, solifenacin, and oxybutynin are extensively metabolized by CYP450, but trospium is not. Trospium is eliminated as unchanged drug, suggesting that it has lower potential for drug-drug interactions and may, therefore, represent a safer treatment option for OAB, particularly in the context of polypharmacy, a significant concern in older adults.