• prostate;
  • needle biopsy;
  • analgesia;
  • patient-controlled;
  • methoxyflurane;
  • ultrasonography;
  • interventional


What's known on the subject? and What does the study add?

Periprostatic infiltration of local anaesthetic (PILA) is accepted as the current ‘gold standard’ of analgesia for TRUS-guided biopsy. However, it does not account for discomfort of anal probe insertion and has not received wide uptake amongst clinicians. A better method is therefore sought. PenthroxTM (methoxyflurane) is an effective systemic analgesic that is self-administered via a hand-held inhaler. Its use in TRUS-guided biopsy has not been previously reported.

An initial experience with a novel analgesic for TRUS-guided biopsy, which appears to be safe and effective. It has led to the planning of a randomised control trial, which will compare Penthrox with PILA for TRUS-guided biopsy.


  • To determine the feasibility of using a novel inhaled analgesic agent (PenthroxTM, methoxyflurane)) for transrectal ultrasonography (TRUS)-guided biopsies of the prostate.

Patients and methods

  • Patients undergoing TRUS-guided biopsies were each given a Penthrox inhaler to self-administer during the procedure and instructed in its use.
  • Immediately after the procedure, patients were asked to rate their pain using a verbal rating scale from 0 to 10.


  • In all, 42 consecutive men underwent a TRUS-guided biopsy.
  • The median pain score was 3.
  • All 42 patients stated they would be happy to undergo the same procedure again. The only adverse effects reported by patients were brief light-headedness and a sickly sweet taste.


  • This study of our initial experience using Penthrox suggests that it may have a role in analgesia for TRUS-guided biopsy.
  • It may provide safe, adequate analgesia that is easy for urologists to use and avoids excessive use of resources.
  • Planning for a randomised control trial comparing Penthrox to the current ‘gold standard’ of prostatic infiltration of local anaesthetic is presently underway.