Efficacy and safety of methoxyflurane (Penthrox) for pain control during water vapor thermal therapy (Rezum) for benign prostatic enlargement.

INTRODUCTION: The safety and efficacy of low dose methoxyflurane disposable inhaler (Penthrox) was assessed in this study of men undergoing Rezum water vapor thermal therapy (WVTT).

MATERIAL AND METHODS: An open-labeled, single-center study was conducted to demonstrate the safety and efficacy of using methoxyflurane inhaler during a Rezum procedure. Patients assessed current pain intensity using a 10-point Visual Analog Scale (VAS) of Pain at 4 timepoints including (1) before any medication, (2) initially after insertion of the rigid cystoscope and before any Rezum treatment, (3) immediately after final injection of Rezum treatment and (4) at discharge. Patients were asked to fill out the Treatment Satisfaction Questionnaire for Medication (TSQM 1.4) and one question about pain relief at discharge. Treating physician also completed the TSQM 1.4.

RESULTS: Ten patients were recruited. Median prostate volume was 53.4 cc (range 24-158 cc). Patients received a median of 10.5 Rezum injections, with a median procedure time of 4.5 minutes. Median VAS scores were 0, 0.1, 0 (primary efficacy outcome) and 0 (out of scale of 10) at the 4 timepoints, respectively. TSQM scores on effectiveness, side effects, convenience and global median satisfaction rated by patients were respectively 69.4, 100.0, 77.8 and 82.1 (out of scale of 100). Treatment satisfaction on pain relief was rated as 4.0 (very good). There were no observed adverse events.

CONCLUSIONS: Methoxyflurane inhaler (Penthrox) was low cost, rapid, feasible and easy to administer as a pain management strategy for Rezum therapy. Further data from a larger comparative study will be conducted.