Effect of muscle relaxants on experimental jaw-muscle pain and jaw-stretch reflexes: a double-blind and placebo-controlled trial.

Abstract

A randomised, double-blind, placebo-controlled three-way cross-over study was performed to investigate the effect of two muscle relaxants (tolperisone hydrochloride and pridinol mesilate) on experimental jaw-muscle pain and jaw-stretch reflexes. Fifteen healthy men participated in three randomised sessions separated by at least 1 week. In each session 300 mg tolperisone, 8 mg pridinol mesilate or placebo was administered orally as a single dose. One hour after drug administration 0.3 ml hypertonic saline (5.8%) was injected into the right masseter to produce muscle pain. Subjects continuously rated their perceived pain intensity on an electronic 10-cm visual analogue scale (VAS). The pressure pain threshold (PPT) was measured and short-latency reflex responses were evoked in the pre-contracted (15% maximal voluntary contraction) masseter and temporalis muscles by a standardised stretch device (1 mm displacement, 10 ms ramp time) before (baseline), 1 h after medication (post-drug), during ongoing experimental muscle pain (pain-post-drug), and 15 min after pain had vanished (post-pain). Analysis of variance demonstrated significantly lower VAS peak pain scores (5.9 +/- 0.4 cm) after administration of tolperisone hydrochloride compared with pridinol mesilate (6.8 +/- 0.4 cm) and placebo (6.6 +/- 0.4 cm) (P=0.020). Administration of pridinol mesilate was associated with a significant decrease in PPTs compared with tolperisone hydrochloride and placebo (P=0.002) after medication, but not after experimental jaw-muscle pain. The normalised peak-to-peak amplitude of the stretch reflexes were not significantly influenced by the test medication (P=0.762), but were in all sessions significantly facilitated during ongoing experimental jaw-muscle pain (P=0.034). In conclusion, tolperisone hydrochloride provides a small, albeit significant reduction in the perceived intensity of experimental jaw-muscle pain whereas the present dose had no effect on the short-latency jaw-stretch reflex.

• Authors: Peter Svensson, Kelun Wang, Lars Arendt-Nielsen
• Journal: European journal of pain (London, England) (Eur J Pain) Vol. 7 Issue 5 Pg. 449-56 ( 2003) ISSN: 1090-3801 [Print] England
• PMID: 12935797 (Publication Type: Clinical Trial, Journal Article, Randomized Controlled Trial, Research Support, Non-U.S. Gov't)

Chemical References

• Muscle Relaxants, Central
• Piperidines
• pridinol
• Tolperisone

Topics

• Adult
• Cross-Over Studies
• Double-Blind Method
• Humans
• Male
• Masticatory Muscles (drug effects, physiopathology)
• Muscle Relaxants, Central (pharmacology)
• Pain (drug therapy, physiopathology)
• Pain Measurement
• Pain Threshold (drug effects, physiology)
• Piperidines (pharmacology)
• Reaction Time (drug effects, physiology)
• Reflex, Stretch (drug effects, physiology)
• Temporomandibular Joint Dysfunction Syndrome (drug therapy, physiopathology)
• Tolperisone (pharmacology)
• Trismus (drug therapy, physiopathology)