Epidural clonidine treatment for refractory reflex sympathetic dystrophy

Area of Science:

• Anesthesiology
• Pain Management
• Neurology

Background:

• Alpha 2-adrenergic agonists administered intraspinally show potential for pain relief in sympathetically maintained pain (SMP) syndromes.
• Reflex sympathetic dystrophy (RSD) is a type of SMP characterized by severe, refractory chronic pain.

Purpose of the Study:

• To evaluate the analgesic efficacy and side effects of epidurally administered clonidine in patients with severe, refractory RSD.
• To compare different doses of epidural clonidine and assess the potential for continuous epidural infusion.

Main Methods:

• A randomized, blinded, placebo-controlled study involving 26 patients with RSD.
• Patients received epidural injections of clonidine (300 or 700 micrograms) or placebo on three consecutive days.
• Pain, sedation, blood pressure, and heart rate were monitored; responders entered a trial of open-label continuous epidural clonidine infusion.

Main Results:

• Epidural clonidine, unlike placebo, provided significant pain relief, sedation, and reduced blood pressure and heart rate.
• The 300 microgram dose of clonidine yielded pain relief and hemodynamic changes comparable to the 700 microgram dose, but with reduced sedation.
• Sustained analgesia was achieved in 19 patients via continuous epidural infusion for an average of 43 days.

Conclusions:

• Epidural administration of clonidine can provide extensive analgesia for RSD.
• Sedation and hypotension are potential limiting factors for bolus epidural clonidine administration in RSD.
• The long-term role of chronic epidural clonidine infusion for RSD requires further investigation.