Oxybutynin for refractory hot flashes in cancer patients

There is little information available on the treatment of hot flashes in patients refractory to pharmaceutical interventions. Anecdotal evidence led to the use of oxybutynin for the management of hot flashes in refractory cancer patients; therefore, we performed a retrospective chart review of such patients to determine the effect of oxybutynin in treating hot flashes and to observe the side effects of the drug in these patients.

A prospective database of all patients treated for hot flashes was started in July 2004 and was retrospectively analyzed as of March 2006. Also included were individual charts preceding July 2004. Fifty-two patient charts were examined. Demographic information was obtained along with baseline severity and frequency of hot flashes, dose and duration of treatment with oxybutynin, patient response to oxybutynin, and side effects.

More than 90% of patients analyzed were refractory to hot flash treatments before starting oxybutynin. Seventy percent of patients showed a partial or excellent response to oxybutynin. The duration of oxybutynin use ranged from 2 weeks to 5 years with more than half of patients currently on oxybutynin or taking oxybutynin for longer than 6 months. Of those patients who experienced an excellent or partial response to treatment, 12% stopped because of documented oxybutynin-related side effects within 4 weeks.

Oxybutynin seems promising in the management of hot flashes with tolerable side effects in the majority of refractory patients. A placebo-controlled, randomized study is being developed to look more closely at the effectiveness of oxybutynin in reducing hot flashes.