after providing consent, you are assigned by a computer system to receive either methoxyflurane (inhaled medication) or the standard oral pain medication used in the emergency department.

if assigned to the methoxyflurane group, you receive a single dose of 6 ml of the liquid for inhalation using a specially designed inhaler. you inhale the medication until you feel pain relief, but the total amount will not exceed 6 ml.

if assigned to the standard‑care group, you receive the usual oral analgesic prescribed for non‑traumatic pain; the exact drug and dose follow the emergency department protocol.

pain intensity is measured with the visual analog scale (vas), a straight line marked from 0 (no pain) to 100 mm (worst possible pain). you mark the point that best represents your pain.

the first measurement is taken at the moment of inclusion, before the medication is given.

subsequent measurements are taken at 3 minutes, and then at 5, 10, 15, 20, 25, and 30 minutes after you receive the medication.

further vas measurements are performed at 60 minutes, 90 minutes, and 120 minutes after randomization to track any changes in pain over time.

if the assigned medication does not provide sufficient relief or pain returns, you may receive a rescue analgesic—an additional pain‑relieving drug from any class—according to the treating clinician’s judgment.

throughout the observation period, you are monitored for any adverse events or serious adverse events, which are recorded by the study staff.

the trial participation ends after the final vas assessment at 120 minutes, unless a rescue analgesic or adverse event requires further medical care.