The aim of this study was to introduce a continuous monitoring of side effects related to sedation-analgesia in the field. A document was completed by physicians on board the ambulances for all prehospital interventions and checked daily by the medical staff. A total of 3605 interventions were evaluated over a 12-month period. Six hundred four patients undertook analgesia and/or sedation: group 1 (spontaneously breathing patients) n = 289 and group 2 (intubated-ventilated patients) n = 315. Sixty-four percent of patients received intravenous opioids in group 1. The anesthetic technique used for intubation was the rapid sequence induction in 70% of patients. Side effects were observed in 5.5% in group 1 (nausea: 2%, hypotension: 1%, hypoxemia: 1%) and 22% of patients in group 2 (hypotension-arrhythmia: 12%, cardiac arrest: 2%, difficult intubation: 5%, hypoxemia: 1%, pulmonary aspiration: 1%, laryngospasm/bronchospasm: 2%). No death was related to these medications. A close monitoring of side effects related to sedation-analgesia must be included in a quality program to improve patient safety in the field.