A Pilot Study on the Use of Methoxyflurane (Penthrox®) for Pain Control in the Emergency Department
Condition: Acute Traumatic Pain
MeSH terms: Emergencies
Study type: Interventional
Phase: Phase 3

Summary: 
      Patients commonly visit the emergency department (ED) for pain after musculoskeletal injury
      and need early treatment with analgesic. Prompt and adequate pain relief can reduce suffering
      and promote early discharge and return to work. Nonsteroidal anti-inflammatory drugs (NSAIDs)
      and opioids are the major injectable analgesic used for moderate to severe pain in EDs in
      Hong Kong. They are given via intravenous or intramuscular route for faster onset of action
      to achieve rapid pain relief in the emergency setting. However, injections are invasive and
      can be distressing for patients. Methoxyflurane (Penthrox®) is recently introduced to our
      emergency department as an inhalational analgesic. It has been granted registration approval
      in Hong Kong since 2018, but it is not widely used in the locality. Methoxyflurane is a
      volatile fluorinated hydrocarbon self-administrated by inhalation through a portable
      hand-held whistle-shaped inhaler device (Penthrox®) to relieve pain associated with trauma or
      minor surgical procedures in stable and conscious patients. In this study, the investigators
      will evaluate the efficacy and safety Penthrox® in the treatment of acute traumatic pain in
      hospital emergency department setting by comparing it to another conventional analgesic
      commonly used.
    


Intervention name(s): Methoxyflurane; Ketorolac
Intervention type(s): Drug; Drug
Intervention description(s): Each patient in the methoxyflurane group will use one Penthrox inhaler under supervision of trained personnel. After priming the inhaler with 3 mL of methoxyflurane, patient is instructed to inhale through the mouthpiece to obtain analgesia, and then exhale back into the mouthpiece so that any unmetabolized methoxyflurane can be adsorbed by activated charcoal chamber. First few breaths should be gentle and then breathe normally through Inhaler. Onset of pain relief is rapid and occurs after 6-10 inhalations. If stronger analgesia is required, patient can cover the diluter hole with a finger during inhalation. Patients are able to titrate the amount of methoxyflurane inhaled and should be instructed to inhale intermittently to achieve adequate pain control.; Each patient in the ketorolac group will receive one dose of 30mg intramuscular ketorolac injected at gluteal muscle by nursing staff as usual daily practice.
Other intervention name(s): Penthrox; Toradol
Intervention MeSH terms: Ketorolac; Methoxyflurane
Allocation: Randomized
Intervention model: Parallel Assignment
Intervention model description: Patients will be enrolled on a convenience basis. After being seen and screened by investigators, patients who meet all inclusion and non-exclusion criteria will be enrolled and randomized 1:1 by drawing from equal preset numbers of envelopes. Patients will receive either inhalational methoxyflurane or intramuscular ketorolac. Patients and investigators are not blinded to the treatment due to the nature of drug administration.
Masking: None (Open Label)
Primary purpose: Treatment