Effects of guanadrel on patients with thyrotoxicosis.

Eleven patients with Graves' disease were treated with guanadrel sulfate and observed for changes in neuromuscular and cardiovascular manifestations. No notable changes in pulse rate or muscle strength were detected in either these patients during a three-day pretreatment period or in five control patients with Graves' disease receiving placebo for six days. Thyroid hormone levels were not altered by seven days of guanadrel sulfate therapy (5 to 20 mg orally every six hours), and no adverse side effects were encountered. Mean supine resting pulse fell from 102 +/- 6 (mean +/- SEM) to 90 +/- 3 beats per minute (P less than .02). The patients' proximal and distal muscle strengths were initially decreased, when compared with healthy subjects, and improved substantially with guanadrel therapy. We conclude that guanadrel sulfate may be useful in the symptomatic management of patients with thyrotoxicosis.