Please confirm that an ethics committee approval has been applied for or granted: Not relevant

Background and Aims Persistent Idiopathic Facial Pain (PIFP) is complex, both in its diagnosis and in its treatment, which currently lacks a gold standard. Recent studies approached the idea that an imbalance in Dopamine release and in D1,D2 receptors expression could be involved in chronic pain, rather than a simple Dopamine depletion. It was in fact demonstrated tjat there is an increase in D2 receptor availability and a decrease in D1/D2 ratio in the striatal dopaminergic system of PIFP animal models. This study aimed to retrospectively evaluate the efficacy of treatment with amitriptyline–perphenazine (a postsynaptic inhibitor of dopamine receptors) association in patients with severe PIFP.

Methods In 2021, 31 patients with severe PIFP were given a regimen dose of amitriptyline–perphenazine, ranging between 10/2 mg and 20/4 mg. All patients were retrospectively analyzed for their pain intensity using a numerical rating scale (NRS) and for their quality of life using a SF-36 questionnaire. Non-normal distributed NRS results were analyzed using the Wilcoxon test for paired data, whereas normally distributed SF-36 questionnaire results were analyzed using the t-test for paired data. A p value < 0.05 was considered statistically significant.

Results Pain values, frequency of acute episodes and quality of life were found to be significantly improved. See table 1.

Conclusions The amitriptyline-perphenazine combination seems to be effective and well-tolerated by patients with PIFP, leading to a whole new therapeutic prospective. It is abundantly clear that dopaminergic pathways play a key role in pain modulation, whereas the underlying mechanisms have yet to be understood, requiring further investigation