Clinical effects of regional intravenous guanethidine (Ismelin) in reflex sympathetic dystrophy.

Twenty patients with documented reflex sympathetic dystrophy were treated with a series of regional intravenous guanethidine blocks. The mean delay between the first clinical symptoms and the start of guanethidine blocks was 3.6 months. The overall result was good in 11 patients, moderate in two patients and poor in seven patients. Poor results are due mainly to incorrect diagnosis and to application either too late in the third phase or too early in the first phase when only signs of increased blood flow are part of the symptomatology. Side effects, except pain after the injection, were few and of minor importance. The tolerance of the procedure may be improved by preceding the injection of guanethidine by an injection of a local anaesthetic agent. It may be concluded that with correct diagnosis and indication, guanethidine injections may play an important part in the treatment of reflex sympathetic dystrophy and may replace sympathetic blocks with local anaesthetics because of the longer duration of action and lower incidence of serious side-effects.