Injectable Therapies for Orofacial Myofascial Pain: A Rapid Review of Randomized Controlled Trials

Background/Objectives: Orofacial myofascial pain (MFP) is one of the leading causes of chronic orofacial pain, often resulting in functional limitations and a compromised quality of life. Intramuscular injection therapies appear to be a promising alternative for patients resistant to conservative treatment. The objective of this rapid review was to synthesize evidence from randomized controlled trials evaluating intramuscular injectable therapies for orofacial myofascial pain. Specifically, the review aimed to compare the clinical effects of different injectable agents on pain intensity, mandibular function, and patient-reported outcomes, and to identify methodological limitations and research gaps within the current evidence base. Methods: A comprehensive search across five databases (ACM, BASE, Cochrane, PubMed, and Scopus) was conducted on March 15, 2026. Randomized controlled trials (RCTs) published between 2022 and 2026 that investigated the use of active injectable agents into the masticatory muscles for clinically diagnosed myofascial pain syndrome were included. Data regarding post-interventional pain intensity, masticatory function, mandibular range of motion, and safety were extracted to compare therapeutic efficacy across interventions. Results: A total of five RCTs met the inclusion criteria. Eligible studies evaluated intramuscular injections of botulinum toxin A, platelet-rich plasma (PRP), magnesium sulfate, and lidocaine, with sample sizes ranging from 30 to 180 participants. Across all interventions, consistent reductions in pain intensity and enhancements in masticatory function were observed. Furthermore, no major adverse events were reported. Conclusions: Intramuscular injectable therapies represent an emerging approach for reducing orofacial myofascial pain, particularly as a treatment for patients with persistent symptoms.