Intranasal analgesia as an alternative to intravenous therapy for acute pain in adult emergency department patients: a systematic review

Analgesia in the emergency department (ED) is often delayed by the need for intravenous (i.v.) access. Intranasal (i.n.) analgesics offer rapid, needle-free delivery, but their effectiveness relative to i.v. therapy in adults remains uncertain. A descriptive systematic review was conducted in accordance with PRISMA guidelines, searching electronic databases from inception through December 2025. Randomized and observational studies enrolling adults with acute ED pain were included if they compared i.n. and i.v. analgesics. Outcomes included pain intensity or change within 60 min, time to analgesia, rescue analgesia, and adverse events. Eighteen studies involving 1950 patients were included. I.v. analgesics produced faster pain reduction at early timepoints (≤5-10 min). I.n. analgesics, including ketamine and opioids, achieved clinically meaningful pain relief within 15-30 min, with similar pain control to i.v. therapy by 30-60 min. Both rescue analgesia and adverse event rates were comparable between routes. I.n. analgesia is an effective and safe option for selected adult ED patients, particularly when i.v. access is delayed or unnecessary. These findings support the selective use of i.n. analgesics as part of ED pain management strategies.