Effects of regional guanethidine infusion in certain painful states.

Guanethidine was infused by the regional intravenous technique into upper and lower limbs of patients with painful hyperpathic states, due to peripheral or central lesions. The relief of pain and hyperpathia occurred within 20 minutes of infusion and lasted between three and 128 hours; in a few patients, the relief has lasted for months. Great reduction in skin conductance and vasodilatation occurred, there being marked variation in the time of onset and duration of these effects. In some cases there was marked pilo-erection. Guanethidine given in this way did not completely block the sympathetic control of digital blood-vessels. There were no effects on sensibility of normally innervated regions.