Aim: The aim of the present investigation was to evaluate the usefulness of tizanidine hydrochloride in the treatment of myofascial pain of the masticatory muscles.
Methods: This work is a preliminary report of clinical experience with the use of tizanidine hydrochloride at the Section of Prosthetic Dentistry, Department of Neuroscience, University of Pisa, Pisa, Italy. During the period from January 2000 to March 2003, 145 patients were given Research Diagnostic Criteria for Temporomandibular Disorders (RDC/TMD) axis I group I diagnosis of myofascial pain in the absence of any painful temporomandibular joint condition. Seventy-eight subjects agreed to suspend any kind of treatment they had undergone and to start assuming tizanidine hydrochloride (SIRDALUD) 4 mg/die per os (2 2- mg tablets a day, 1 in the morning and 1 after dinner) for 2 weeks. All underwent a clinical assessment according to RDC/TMD guidelines at baseline time and were re-evaluated at the end of the treatment period.
Results: At the end of the treatment period all patients had improved; 42/78 patients (53.8%) showed absence of clinical symptoms; 18/78 (23.1%) showed a good improvement, still presenting a low number of painful sites, but not satisfying RDC/TMD parameters for diagnosis of myofascial pain; 18/78 (23.1%) showed only a slight improvement, still presenting a high number of painful sites and satisfying RDC/TMD parameters for diagnosis of myofascial pain.
Conclusion: Given the absence of papers on the use of tizanidine hydrochloride in the treatment of myofascial pain of the masticatory muscles, the present investigation could provide some preliminary data about its possible efficacy. Randomized and controlled clinical trials are needed to confirm these results.