In adults, what is the Ketamine dose for acute pain from trauma, given via IV over five minutes, and can be repeated after 15 minutes if pain persists, and which routes are prohibited?

• A. 0.1 mg/kg IV over 2 minutes; may repeat after 5 minutes; IVP allowed
• B. 0.3 mg/kg to max 30 mg in 50-100 ml NS via IV over five minutes. May repeat after 15 minutes if pain score remains at five or higher. Do not administer IVP, IO, IM, or IN.
• C. 0.3 mg/kg IV push; may repeat after 15 minutes
• D. 0.5 mg/kg IM; no repeats

Answer: (B)

Ketamine provides analgesia at subanesthetic doses by blocking NMDA receptors, which helps reduce central sensitization and pain perception without causing full anesthesia. For adults with acute traumatic pain, the recommended approach is 0.3 mg/kg given intravenously, diluted in 50–100 mL of normal saline and infused over five minutes, with a maximum of 30 mg. If pain remains at a clinically significant level after about 15 minutes, a repeat dose at the same 0.3 mg/kg (not exceeding the 30 mg total per dose) can be given. This infusion method, with a 15-minute reassessment window, allows controlled delivery and safer monitoring of effects and side effects.

Routes other than IV infusion are avoided because they can lead to unpredictable absorption and peak concentrations, increasing the risk of adverse effects such as dissociation, airway reflex changes, or hemodynamic instability. IV push, IO, IM, and intranasal administration are not allowed in this protocol, as the infusion over five minutes provides a safer, more controllable analgesic effect in the acute trauma setting.