Objective: To determine whether naloxone administered i.v. to out-of-hospital patients with suspected opioid overdose would have a more rapid therapeutic onset than naloxone given subcutaneously (s.q.).
Methods: A prospective, sequential, observational cohort study of 196 consecutive patients with suspected opioid overdose was conducted in an urban out-of-hospital setting, comparing time intervals from arrival at the patient's side to development of a respiratory rate > or =10 breaths/min, and durations of bag-valve-mask ventilation. Subjects received either naloxone 0.4 mg i.v. (n = 74) or naloxone 0.8 mg s.q. (n = 122), for respiratory depression of <10 breaths/min.
Results: Mean interval from crew arrival to respiratory rate > or =10 breaths/min was 9.3 +/- 4.2 min for the i.v. group vs 9.6 +/- 4.58 min for the s.q. group (95% CI of the difference -1.55, 1.00). Mean duration of bag-valve-mask ventilation was 8.1 +/- 6.0 min for the i.v. group vs 9.1 +/- 4.8 min for the s.q. group. Cost of materials for administering naloxone 0.4 mg i.v. was $12.30/patient, compared with $10.70/patient for naloxone 0.8 mg s.q.
Conclusion: There was no clinical difference in the time interval to respiratory rate > or =10 breaths/min between naloxone 0.8 mg s.q. and naloxone 0.4 mg i.v. for the out-of-hospital management of patients with suspected opioid overdose. The slower rate of absorption via the s.q. route was offset by the delay in establishing an i.v.