Repeated use of pain relief puffer may damage liver

Repeated exposure to a widely-used anaesthetic may cause liver disease, according to a case study published in the Medical Journal of Australia.

The case has implications for the way methoxyflurane – which is used for rapid short-term pain relief during brief, painful procedures – is prescribed, the researchers say.

Methoxyflurane is no longer used in general anaesthesia due to its toxic effects on the liver, but side effects are rare from the single-dose puffers carried by paramedics.

Doctors examined a 33-year-old woman who was admitted to the Royal Brisbane and Women’s Hospital with acute hepatitis, four weeks after beginning a series of treatments for varicose veins.

She had no history of alcohol abuse, no risk factors for viral hepatitis and no family history of hepatitis or liver disease, Dr Kacey O’Rourke, the treating medical registrar said.

However, during each of her three vein treatments, she was given methoxyflurane via an inhaler.

“It seems the exposure to methoxyflurane in our patient was the likely cause of acute hepatitis, and it may be that repeated exposure was a contributing factor,” Dr O’Rourke said.

“This observation has implications for the way methoxyflurane is prescribed, including its use for procedural analgesia in cases in which several procedures (and hence, repeated dosing) are required.”

The patient recovered and has been advised to avoid future exposure to methoxyflurane.

(Source: Australian Medical Association: Medical Journal of Australia)