Penthrox inhaler analgesia in transrectal ultrasound-guided prostate biopsy

Periprostatic injection of local anaesthetic (PILA) has been shown to significantly reduce pain in patients undergoing transrectal ultrasound-guided prostate biopsy (TRUSPB). However, this method does not address pain that is associated with ultrasound probe insertion, and the injection of local anaesthetic itself causes pain. The aim of this study was to explore the efficacy of methoxyflurane delivered by a Penthrox inhaler as a novel method of pain relief during TRUSPB.

From July 2012 to July 2013, 64 patients were scheduled at a single centre to undergo TRUSPB while receiving analgesia via Penthrox inhaler. Fifteen minutes after the biopsy procedure, these patients were asked to complete a pain score survey using a 10-cm visual analogue scale (VAS) to separately report the degree of pain experienced during digital rectal examination (DRE), ultrasound probe insertion and core biopsy.

The median pain scores on a 10-cm VAS were 2.0, 2.4 and 3.0 during DRE, probe insertion and needle biopsy, respectively, while using the Penthrox inhaler. Of the 64 patients, 11 had undergone TRUSPB previously receiving PILA. In these patients, PILA was significantly better than the Penthrox inhaler for pain relief during needle biopsy (median pain score 2.0 versus 4.0; P = 0.012).

The Penthrox inhaler appears to be a safe and effective method of analgesia for TRUSPB. Patients who had experienced both PILA and Penthrox reported pain scores that significantly favoured PILA over the Penthrox inhaler.