Objective To assess the effects of naproxen sodium-codeine phosphate, naproxen sodium-dexamethasone, and naproxen sodium on myofascial pain. Methods This randomized, double-blind prospective clinical study was conducted with patients who applied with the complaint of pain in the temporomandibular region. A total of 169 patients were randomly divided into four groups and received the following treatments: Group A: naproxen sodium 550 mg; Group B: naproxen sodium 550 mg + codeine phosphate 30 mg; Group C: naproxen sodium 550 mg + single-dose dexamethasone 8 mg, and Group D: paracetamol 500 mg. Results Of the patients, 132 were female, and 37 were male, with a mean age of 27.04 +/- 10.56 (18-69 years). Analgesic efficiency of the naproxen sodium-codeine phosphate group was the most effective at the 2nd week and 4th week (p< 0.05). Conclusion Naproxen sodium-codeine phosphate might be preferred as an analgesic in similar cases with severe myofascial pain.