Can benztropine be used for analgesia of patients with acute MSK pain?
Date First Published:
February 4, 2021
Last Updated:
April 8, 2021
Report by:
Ben Forestell, Resident Physician (McMaster University)
Search checked by:
January 25, 2020, McMaster University
Three-Part Question:
Does [benztropine] [improve pain scores] for patients with [acute musculoskeletal pain]?
Clinical Scenario:
You see a 32-year-old man in the rapid assessment zone of your emergency department with acute neck pain a few hours after helping his friends move to their new apartment. There was no direct trauma and he has no neurological deficits and no bony tenderness. He has tried acetaminophen and ibuprofen but he continues to have limited range of motion and significant pain on the left side of his neck.
Search Strategy:
OVID Medline and EMBASE
Search Details:
(benztropine.mp or exp Benztropine OR cogentin.mp) AND (back pain.mp or exp Back Pain OR spasm.mp or exp Spasm OR msk pain.mp or exp Musculoskeletal Pain OR exp Acute Pain or pain.mp or exp Low Back Pain or exp Neck Pain or exp Pain or exp Pain Management)
Outcome:
716 studies imported for screening
t28 duplicates removed
688 studies screened
t673 studies irrelevant
15 full texts assessed
t13 studies excluded
2 relevant studies were identified
t28 duplicates removed
688 studies screened
t673 studies irrelevant
15 full texts assessed
t13 studies excluded
2 relevant studies were identified
Relevant Paper(s):
| Study Title | Patient Group | Study type (level of evidence) | Outcomes | Key results | Study Weaknesses |
|---|---|---|---|---|---|
| Benztropine for acute muscle spasm in the emergency department. Epstein, N.L. 2001 Canada | Eight emergency department patients (16-42 yo) with acute onset spasmodic neck and back pain. Benztropine 2-4 mg IM. | Case series | Pain (using ten-point visual analog scale) | All patients had improvement in pain scores after treatment | Small, single investigator, single-arm, case series Unclear if consecutive enrolment |
| Benztropine for the relief of acute non-traumatic neck pain (wry neck): A randomised trial. Asha, S.E., Kerr, A., Jones, K., & McAlpine, A. 2014 Australia | Thirty emergency department patients with acute, non-traumatic neck pain. Benztropine 2mg IM vs placebo IM injection. | Placebo-controlled, randomized-controlled trial | Mean pain (using ten-point verbal numeric rating scale) at 30 min after treatment | No significant difference in pain scores between groups (5.6 v 6.2, p = 0.40) | Compared post-treatment scores of benztropine v placebo, rather than change in scores pre to post-treatment between groups Small study, underpowered |
Author Commentary:
There is limited evidence on the use of benztropine for acute musculoskeletal pain. Our only high-quality evidence shows no evidence of benefit for treating acute spasmodic neck pain, and increased adverse events, when administering benztropine. The results of this study are limited by it’s small sample size.
Bottom Line:
Benztropine should not be routinely used in the treatment of acute musculoskeletal pain.
References:
- Epstein, N.L.. Benztropine for acute muscle spasm in the emergency department.
- Asha, S.E., Kerr, A., Jones, K., & McAlpine, A.. Benztropine for the relief of acute non-traumatic neck pain (wry neck): A randomised trial.