Efficacy of duloxetine as a migraine preventive medication: possible predictors of response in a retrospective chart review.

OBJECTIVE: This case series is a retrospective chart analysis conducted to evaluate the efficacy of duloxetine as a migraine preventive medication and to suggest possible predictors of response.
BACKGROUND: Duloxetine, a relatively new selective serotonin and norepinephrine reuptake inhibitor, is FDA-approved for treatment of depression and diabetic peripheral neuropathic pain. The efficacy of duloxetine as a headache preventive medication is currently unknown.
METHOD: A retrospective chart review was performed using the electronic medical records of Headache Wellness Center, a headache specialty practice in Greensboro, North Carolina. From January 2004 to December 2006, 65 patients were identified who were prescribed duloxetine for migraine prevention for at least 2 months. Doses ranged from 30 mg qd to 90 mg qd. Frequency, severity, and impact of migraine disability were measured at baseline and compared to values obtained after 2 months of treatment.
RESULTS: The total patient sample demonstrated a reduction in mean monthly headache frequency from 19.40 (SD=7.1) to 15.70 (SD=8.2) (P= .01). The 50% responder rate was 22%. In subset analysis, individuals with abnormal baseline Zung anxiety scores demonstrated a greater reduction in mean monthly headache frequency (4.28, P= .03) and a greater responder rate (25%) than those in the total patient sample. Non-statistically significant trends were observed in those patients with abnormal baseline Zung Depression scores exhibiting a less robust mean monthly migraine reduction (2.75, P= .18) than those with normal baseline depression scores (3.42, P= .07).
CONCLUSIONS: Duloxetine demonstrates minimal effectiveness as a headache preventive medication. An interesting trend suggests that the presence of anxiety may be a positive predictor in treatment with duloxetine.