‘Green Whistle’ Inhaled Painkiller Found to be Quickest Form of Pain Relief in Ambulances

A new study has revealed that an inhaled painkiller recently introduced to the UK can relieve severe pain two to three times quicker than conventional therapies, such as gas and air or morphine, following traumatic injury.

The year-long MAPIT study, led by Professor Aloysius Niroshan Siriwardena of the University of Lincoln, UK, and carried out by East Midlands Ambulance Service, showed that the drug Penthrox (methoxyflurane), is significantly more effective than routine therapies, in terms of speed of pain reduction.

Treatment during the first hour after a traumatic incident is vital to improve patient survival and good analgesia can mean easier management of the injury and increased potential to avoid chronic pain later in life, the researchers say. Despite this, less than a third of people in UK ambulances are given appropriate pain relief.

The drug methoxyflurane, which has been dubbed the ‘green whistle’ has already been proven to be a convenient and effective option for pain relief, leading to patients spending less time in hospital emergency departments. Although it is used regularly in UK hospitals, it is not widely used in ambulances.

Data from the MAPIT study, presented at the 999 EMS Research Forum Annual Conference in the UK this week (23 March 2021), offers paramedics and technicians another first-line treatment option for trauma patients, which can reduce the amount of time patients spend in severe pain and offers an effective alternative to opioid pain relief.

As a single-use product that does not require canisters, additional breathing masks or tubes and is disposed of after use via a sealable plastic bag, this drug also minimises the potential of inadvertently spreading infection at the scene of an incident or in an ambulance, of particular importance currently as the NHS continues to face exceptional pressure from the COVID-19 pandemic.

Chief Investigator, Professor Aloysius Niroshan Siriwardena, a specialist in quality improvement in primary and prehospital healthcare at the University of Lincoln, said: “There are many barriers to adequate pain relief. This study is the first to compare methoxyflurane with all other commonly used analgesics in the prehospital setting and the superior results add to the weight of positive findings from other UK and European hospital studies.
“From an academic perspective, it is an important addition to the evidence, and we look forward to seeing how greater uptake impacts patients in other ambulance trusts.”

Dr Leon Roberts, Medical Director for East Midlands Ambulance Service NHS Trust, which carried out the study, commented: “Rapid and effective pain relief is undeniably important in the prehospital setting and this study showed that emergency care staff have access to a well-tolerated treatment, which is easy to administer. EMAS is proud to be a leading organisation in prehospital research collaborating with key partners such as the University of Lincoln, who has analysed and evaluated this data.”

Reference: Smith M, Rowan E, et al. Evaluation of the effectiveness and costs of inhaled methoxyflurane versus usual analgesia for prehospital injury and trauma. Presented at 999 EMS Research Forum Annual Conference, March 2021.