Early clinical experience with clonidine in spinal spasticity.

The centrally active, alpha-2 adrenergic receptor agonist clonidine was given to 12 spinal cord injury patients with problematic spasticity not adequately controlled by recognized spasmolytic drug therapy. Five patients had an excellent reduction and 2 patients had some reduction in clinical spasticity (average dose 0.39 mg daily). Four of the 7 responders discontinued clonidine because of adverse reactions after an average of ten weeks of therapy. Three responders have continued to tolerate the drug well with excellent control of spasticity for 18 to 34 months. Five patients had no change in clinical spasticity (average dose of 0.24 mg daily). Three of the non-responders discontinued clonidine because of adverse reactions after an average of three weeks of therapy. Significant associated adverse reactions included syncopal seizures (3), cerebrovascular accident (1), deep vein thrombosis (1), autonomic hyperreflexia (3), lethargy/drowsiness (3), and nausea/vomiting (1). Possible mechanisms of action for clonidine to affect spasticity and the unstable cardiovascular system of quadriplegics is discussed. While spinal cord injured patients with severe spasticity may benefit from clonidine, great caution is recommended during its use until further study establishes safe parameters of administration and efficacy is confirmed on controlled studies.