Sympathetic blockade of isolated limbs by intravenous guanethidine.

As a result of experience at the Montreal General Hospital, it has been found that intravenous guanethidine blockade of extremities has therapeutic, prophylactic and diagnostic value in conditions where the aetiology is a disorder of sympathetic nervous conduction. The properties of guanethidine, namely its selective action on blocking the sympathetic nervous system peripherally, together with its long half time and rapid tissue fixation, render it a very useful drug in techniques where an isolated limb is blocked with guanethidine. Experience on a 18-month basis suggests that the procedure of intravenous guanethidine blockade offers exceptionally good results for a non-invasive technique. Work is now in progress to study the possible use of guanethidine in the treatment of phantom limb pain, and also to see whether other drugs, such as thymoxamine, could be used in a similar fashion to guanethidine.