Penthrox® (Methoxyflurane) Inhalation 3ml also known as the “green whistle” is now available to medical practitioner’s

Penthrox ® (Methoxyflurane) Inhalation 3ml also known as the “green whistle” is now available to medical practitioner’s at

Penthrox (Methoxyflurane) Vivomed Green Whistle
Penthrox® (Methoxyflurane) now availabe from

Penthrox ®, also known as ‘the green whistle’ in Australia and New Zealand where it has been on the market for several years, could transform the management of emergency pain relief especially in sports medicine.

Penthrox ® is a hand-held inhaler used by adult trauma patients delivered via the inhaler to provide fast, effective pain relief within 6 – 10 breaths and is now available from the UK and Ireland’s leading sports medicine company Vivomed.

The innovative pocket-sized inhaler delivers an analgesic medicine quickly to trauma patients which could be especially important in a sporting environment where up until now the best practice option has been using ENTONOX® which is transported in pressurised cylinders and requires expensive consumables such as demand valves and aspirators.

The main advantages for Penthrox ® over ENTONOX® for sports teams and sports medical professionals is twofold:

  1. The size – the Penthrox ® inhaler is only about 15cm long and weighs about 300grams
  2. Teams can easily transport and fly with Penthro x® as unlike ENTONOX® it is not kept in a pressurised container.

What comes in the pack:

  • 1x 3ml Penthrox ® (Methoxyflurane) vial
  • 1x Inhaler
  • 1x AC Chamber

Penthrox ® is now available from UK and Ireland’s leading sports medicine supplier and the only one with a licensed pharmacy

As Penthrox ® is a Prescription only Medicine (POM) this can be purchased by Doctors through Vivomed’s secure online pharmaceutical ordering system Webmeds.

To access this please visit or contact the Vivomed office on +44(0) 28 44617666


Method of Administration

Instructions on the preparation of the PENTHROX Inhaler and correct administration are provided in the Figures below.

1 Ensure the Activated Carbon (AC) Chamber is inserted into the dilutor hole on the top of the PENTHROX Inhaler.  Penthrox now available from
2 Remove the cap of the bottle by hand. Alternatively, use the base of the PENTHROX Inhaler to loosen the cap with a ½ turn. Separate the Inhaler from the bottle and remove the cap by hand.  Penthrox now available from
3 Tilt the PENTHROX Inhaler to a 45° angle and pour the total contents of one PENTHROX bottle into the base of the Inhaler whilst rotating.  Penthrox now available from
4 Place wrist loop over patient’s wrist. Patient inhales through the mouthpiece of the PENTHROX Inhaler to obtain analgesia. First few breaths should be gentle and then breathe normally through Inhaler.  Penthrox now available from
5 Patient exhales into the PENTHROX Inhaler. The exhaled vapour passes through the AC Chamber to adsorb any exhaled methoxyflurane.  Penthrox now available from
6 If stronger analgesia is required, patient can cover dilutor hole on the AC chamber with finger during use.  Penthrox now available from
7 Patient should be instructed to inhale intermittently to achieve adequate analgesia. Continuous inhalation will reduce duration of use. Minimum dose to achieve analgesia should be administered.  Penthrox now available from
8 Replace cap onto PENTHROX bottle. Place used PENTHROX Inhaler and used bottle in sealed plastic bag and dispose of responsibly.  Penthrox now available from



One bottle of 3 mL PENTHROX to be vaporised in a PENTHROX inhaler. On finishing the 3 mL dose, another 3 mL may be used. Dose of PENTHROX should not exceed 6 mL in a single administration. Methoxyflurane may cause renal failure if the recommended dose is exceeded. The lowest effective dosage of PENTHROX to provide analgesia should be used.

Onset of pain relief is rapid and occurs after 6 – 10 inhalations. Patients should be instructed to inhale intermittently to achieve adequate analgesia. Patients are able to assess their own level of pain and titrate the amount of PENTHROX inhaled for adequate pain control. Continuous inhalation provides analgesic relief for up to 25-30 minutes. Intermittent inhalation may provide longer analgesic relief. Patients should be advised to take the lowest possible dose to achieve pain relief.

The frequency at which PENTHROX can be safely used is not established. Administration on consecutive days is not recommended and the total dose to a patient in a week should not exceed 15 ml (see section 4.4).


PENTHROX should not be used in children under 18 years.


  • Use as an anaesthetic agent.
  • Hypersensitivity to PENTHROX or any fluorinated anaesthetic.
  • Malignant hyperthermia: patients with known or genetically susceptible to malignant hyperthermia or a history of severe adverse reactions in either patient or relatives.
  • Patients who have a history of showing signs of liver damage after previous Methoxyflurane use or halogenated hydrocarbon anaesthesia.
  • Clinically significant renal impairment.
  • Altered level of consciousness due to any cause including head injury, drugs, or alcohol.
  • Clinically evident cardiovascular instability.
  • Clinically evident respiratory depression.


For full prescribing information for Penthrox® including Summaries of Product Characteristics (SPCs) and Patient Information Leaflets (PILs).

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One Response

  1. Akb medical solutions

    I am an anaesthetist and also work for a private medical company providing medical cover for cage fighting, Mma and boxing (I am also a Member of the British boxing medical board)
    We recently needed to use penthrox for a traumatic tib/fib # at a recent event for cage warriors, and it was highly effective.
    I would like to discuss adding penthrox to our emergency pre-hospital medical kit and would be grateful if someone could contact me

    Kind regards

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