Overactive Bladder Prescribing Considerations: The Role of Polypharmacy, Anticholinergic Burden, and CYP2D6 Drug‒Drug Interactions

Overactive bladder (OAB) is a common disorder in the general population, and the prevalence increases with age. Adults with OAB typically have a greater number of comorbid conditions, such as hypertension, depression, and dementia, compared with adults without OAB. Subsequent to an increased number of comorbidities, adults with OAB take a greater number of concomitant medications, which may increase the risk of potentially harmful drug‒drug interactions. There are two important considerations for many of the medications approved for the treatment of OAB in the USA: anticholinergic burden and potential for drug‒drug interactions, notably related to cytochrome P450 (CYP) 2D6, which is responsible for the metabolism of approximately 25% of all drugs. A substantial number of drugs used for the treatment of OAB and comorbid conditions (e.g., cardiovascular and neurologic disorders) are CYP2D6 substrates or inhibitors. Furthermore, a substantial number of drugs with CYP2D6 properties also have strong anticholinergic properties. Here, we review polypharmacy associated with OAB and its common comorbidities, identify drugs with reported anticholinergic properties, and provide an overview of clinically relevant drug‒drug interactions in the treatment of OAB as they relate to CYP2D6 metabolism. This review aims to provide clinicians with essential information necessary for making treatment decisions when managing OAB.