Hydroxyzine for lowering patient's anxiety during prehospital morphine analgesia: A prospective randomized double blind study.

STUDY OBJECTIVE: Hydroxyzine is an antihistamine drug used for symptomatic relief of anxiety and tension. We hypothesized that managing the anxiety of patients with severe pain by adding hydroxyzine to a conventional intravenous morphine titration would relieve their pain more effectively.

METHODS: This was a randomized, double-blind, controlled group study of prehospital patients with acute pain scored greater than or equal to 6 on a 0-10 verbal numeric rating scale (NRS). Patients'anxiety was measured with the self-reported Face Anxiety Scale (FAS) ranking from 0 to 4. The percentage of patients with pain relief (NRS score ≤ 3) 15 min after the first injection was the primary outcome.

RESULTS: One hundred forty patients were enrolled. Fifty-one percent (95% CI 39% to 63%) of hydroxyzine patients versus 52% (95% CI 40% to 64%) of placebo patients reported a pain numeric rating scale score of 3 or lower at 15 min. Ninety-one percent (95% CI 83% to 98%) of patients receiving hydroxyzine reported no more severe anxiety versus 78% (95% CI 68% to 88%) of patients with placebo (p > 0.05). Adverse events were minor, with no difference between groups (6% in hydroxyzine patients and 14% in placebo patients).

CONCLUSION: Addition of hydroxyzine to morphine in the prehospital setting did not reduce pain or anxiety in patients with acute severe pain and therefore is not indicated based on our results.