An ambulatory trial of guanfacine

1. The effects of acute and long‐term treatment with guanfacine on ambulatory BP were studied. 2. The first day of therapy with guanfacine 1 mg produced a small reduction in BP whereas chronic therapy with doses up to 6 mg given once daily produced a substantial smooth reduction throughout the whole 24 hours. 3. There were no noticeable symptoms or rebound effects on withdrawal of the drug; side‐effects, were, however, prominent during therapy. 4. The drug reduced BP during dynamic exercise but did little during isometric exercise; no postural hypotension was noted during tilting.