Use of onabotulinumtoxinA for overactive bladder with concomitant warfarin

The symptoms of overactive bladder (OAB) can be treated with oral medications using a variety of antimuscarinic medications and, more recently, mirabegron, a beta-3 agonist. However, the use of these medications may be limited for patients because of adverse drug reactions, contraindications, and those who are refractory to oral medications. Recently, intravesical injections of onabotulinumtoxinA (onaBoNTA) have been proven to be safe and effective as an alternative to oral OAB medications. Although this procedure is typically thought to be outside the realm of a consultant pharmacist, there are incidences in which a pharmacist can make a substantial impact on patient care. The patient, a 71-year old female, presents to her urologist for evaluation to assess appropriateness of intravesical onaBoNTA injections. She has failed multiple oral medications for the treatment of her OAB with urge incontinence. The procedure is further complicated by the patient's past medical history of atrial fibrillation (A fib), deep vein thrombosis (DVT), and pulmonary embolism (PE) that require anticoagulation with warfarin therapy. This case demonstrates the use of onaBoNTA for OAB in a patient concomitantly receiving warfarin for A fib, PE, and DVT. Specifically, it demonstrates discontinuation, bridge therapy, and reinitiation of warfarin on a patient undergoing intravesical injections of onaBoNTA for OAB, and a collaborative approach to care between a pharmacist and a urologist.