The use of oxytocin and relaxin in the treatment of refractory chronic pain with mixed characteristics (neuropathic and myofascial pain). Case report

ABSTRACT BACKGROUND AND OBJECTIVES: Some studies have related the use of synthetic oxytocin for the treatment of painful syndromes that relies on central and peripheral modulation mechanisms of pain. Thus, the objective of this study was to report a case of a patient with a refractory chronic pain of mixed characteristics (myofascial and neuropathic pain) who responded to the treatment with synthetic oxytocin and relaxin. CASE REPORT: Female patient, 41 years old, presenting a 10-year history of right hemifacial pain after dental surgery, with neuropathic characteristics, diagnosed as atypical facial pain (atypical trigeminal neuralgia). Later, she developed pain in the right cervical region, radiating to the shoulder, with several muscle trigger points in the pericranial region, suggestive of myofascial pain. After treatment with antidepressants, neuromodulators, anesthetic blockade, capsaicin and topical lidocaine, with partial results and pain recurrence, she started treatment with intramuscular oxytocin and oral relaxin. Over the year she followed the proposed treatment, she presented light pain, greater pain-free intervals, reduced need of pain blockade, improved tolerance to physical exercise and of the local face allodynia. CONCLUSION: Despite the new drugs, procedures, and protocols to treat chronic pain, the patients often present unsatisfactory outcomes. Many times, there are situations of mixed pain (neuropathic and myofascial pain) with central and peripheral sensitization, resulting in worse prognostic and refractoriness. In this case, synthetic oxytocin and relaxin presented a satisfactory response.