Amitriptyline in the prophylaxis of central poststroke pain. Preliminary results of 39 patients in a placebo-controlled, long-term study.

BACKGROUND AND PURPOSE We performed a double-blind, placebo-controlled study to investigate the effectiveness of amitriptyline for the prophylactic treatment of patients with acute thalamic stroke in preventing central poststroke pain. METHODS Subject received, in a randomized sequence, either amitriptyline titrated from 10 to 75 mg in extended-release form or placebo over a therapy period of 365 days. We documented the time when pain developed; the intensity, type, site, and distribution of pain; and the presence/absence and type of allodynia. RESULTS Thirty-nine patients (23 women and 16 men; age range, 36 to 68 years) with central poststroke pain participated. The placebo group showed a pain rate of 21% within 1 year after the diagnosis of thalamic stroke compared with 17% in the group under prophylactic treatment with amitriptyline. Average (SE) time to pain was 318 (23) days for patients in the placebo group and 324 (24) days for patients in the amitriptyline group. CONCLUSIONS With the achieved sample sizes of this study and a pain rate of approximately 21% in the placebo group, any near-perfect pain protection would have been detected. Near-perfect pain protection, in this context, refers to pain in <2.4% of the recruited patients treated with amitriptyline or in approximately 89% of placebo-treated patients. Larger studies are recommended to test the hypothesis that prophylactic amitriptyline reduces but does not completely prevent central poststroke pain.