What is the best first choice oral drug therapy for OAB?

The management of overactive bladder (OAB) involves lifestyle changes and conservative measures in the first instance with the use of liquid/dietary advice, weight loss, and bladder training. Thereafter oral pharmacotherapy is instigated in symptomatic patients. Antimuscarinics and beta 3 agonists form the main classes of drug therapy in this field. Views on what is the best first line OAB treatment is changing based on recent evidence and adverse event profiles of these medications.