A comparison of regional intravenous guanethidine and reserpine in reflex sympathetic dystrophy. A controlled, randomized, double-blind crossover study.

Both regional intravenous guanethidine and reserpine have been reported as effective in the treatment of reflex sympathetic dystrophy. Reserpine depletes storage of norepinephrine, and guanethidine interferes with transport of norepinephrine while depleting storage in the sympathetic nerve terminal. The purpose of this study was to compare drug efficacy in double-blind fashion. Twelve patients, 10 of whom had previous stellate or lumbar sympathetic blocks, were entered into this double-blind cross-over study. Each patient successively received 20 mg guanethidine in 50 ml 0.5% lidocaine, 1.25 mg reserpine in 50 ml 0.5% lidocaine, and 50 ml 0.5% lidocaine with a 1-week interval between medications. At the end of the study and before the code was broken, each patient had the option of continuing treatment with any of the three drugs: the patient merely asked for the first, second, or third drug. Pain assessment used verbal ordinal, numeric, and visual analog scales. Follow-up lasted for a minimum of 6 months. Changes in pain intensity for the first 3 days did not differ significantly among guanethidine, reserpine, and control groups. Pain relief from 2 to 14 months was achieved in two patients receiving reserpine, one receiving guanethidine, and none receiving lidocaine. None of the patients experienced permanent relief. No difference was found between reserpine and guanethidine.