QTc Shortening on Electrocardiogram With Amitriptyline May Indicate No Effect on Pain Relief in Burning Mouth Syndrome.

OBJECTIVE: Burning mouth syndrome (BMS) is an intractable chronic pain disorder characterized by a burning sensation without organic abnormalities in the oral mucosa. Amitriptyline may be effective for BMS or, conversely, may exacerbate pain. QTc is necessary for monitoring psychotropic adverse effects, but it is not known if it is a predictor of efficacy for BMS. We investigated the efficacy of amitriptyline in BMS and its effect on QTc. METHODS: Visual analog scale and electrocardiogram were examined before and 1 month after treatment in 51 consecutive patients diagnosed with BMS according to the International Classification of Headache Disorders, Third Edition (ICHD-3), criteria and treated with amitriptyline. RESULTS: There were 26 amitriptyline responders and 25 nonresponders, with no differences in age, sex, and amitriptyline dosage. Amitriptyline responders showed little change in QTc, whereas nonresponders showed a trend toward significantly shorter QTc. Changes in visual analog scale correlated statistically significantly with changes in QTc (Spearman rank correlation coefficient: 0384; P = 0.0054). The degree of pain tended to worsen with QTc shortening. CONCLUSION: Amitriptyline provides analgesia in about half of BMS patients, but some BMS patients have worse pain with amitriptyline. Not only do changes in the QTc detect amitriptyline adverse effects with prolongation, but also, conversely, its shortening predicts amitriptyline ineffectiveness.