The purpose of this systematic review is to investigate current evidence for analgesic use in the prehospital environment using expert military and civilian opinion to determine the important clinical questions. There was a high degree of agreement that pain should be no worse than mild, that pain relief be rapid (within 10 minutes), that patients should respond to verbal stimuli and not require ventilatory support, and that major adverse events should be avoided. Twenty-one studies provided information about 6212 patients; the majority reported most of the outcomes of interest. With opioids 60-70% of patients still had pain levels above 30/100 mm on a Visual Analogue Scale after 10 minutes, falling to about 30% by 30-40 minutes. Fascia iliaca blocks demonstrated some efficacy for femoral fractures. No patient on opioids required ventilatory support; two required naloxone; sedation was rare. Cardiovascular instability was uncommon. Main adverse events were dizziness or giddiness, and pruritus with opioids. There was little evidence regarding the prehospital use ofketamine.