Negative predictors of clinical response to amitriptyline in Japanese patients with migraine

Background Migraine is the most common neurological disease. Recently, there is a wide variety of prophylactic drugs, but their effects differ among individuals. Aim To investigate clinical factors affecting the response to amitriptyline therapy and establish a scoring system for predicting the negative response to prophylactic therapy. Methods We examined clinical factors from medical records of 29 consistent responders (CRs) and 21 inconsistent responders (IRs) to amitriptyline. Results Multivariate analysis revealed that a past history of medication overuse headache (MOH) and allodynia from associated symptoms were significant factors that independently contributed to a negative response. Odds ratio of MOH was 4.489 (no vs yes; 95% CI = 1.109–14.224), and odds ratio of allodynia was 4.489 (yes vs no; 95% CI = 1.109–14.224). A predictive index (PI) of the negative response to amitriptyline in patients with migraine was calculated using the regression coefficients of these two factors as integers, and the index was significantly higher for IRs than CRs (1.33 ± 0.58 vs 0.76 ± 0.69, mean ± SD, P = 0.003) Conclusion The obtained PI may represent an appropriate scoring system for negative responses in patients using amitriptyline.