Reflex changes induced by clonidine in spinal cord injured patients.
In a single blind study of 6 spinal cord injured (SCI) men, the effects of clonidine, a selective alpha-2 adrenergic agonist, on spasticity were compared to diazepam and placebo. Since a potential side-effect of clonidine is postural hypotension, a combination of clonidine and desipramine was also tested. Vibration of the leg will inhibit the H reflex in a normal subject; whereas, this inhibition is markedly reduced in SCI patients with spasticity. A vibratory inhibition index (VII) was derived for each treatment. The pre-treatment VII was 92.08 +/- 3.15%; for SCI subjects, compared to 46.5 +/- 7.7% for 6 normal subjects. Clonidine significantly reduced the mean index of SCI patients to 59.42 +/- 3.91% (p less than 0.001). The VII for placebo, diazepam and the clonidine-desipramine combination were not statistically different than the pre-treatment values in SCI patients. In conclusion, clonidine has an anti-spasticity effect in SCI patients, both subjectively, and objectively, in terms of vibratory inhibition of the H reflex.
Nance
P W
PW
Division of Physical Medicine and Rehabilitation, Dalhousie University, Halifax, Nova Scotia, Canada.
Shears
A H
AH
Nance
D M
DM
D000316:Adrenergic alpha-Agonists / Q000627:therapeutic use*; D000328:Adult; D003000:Clonidine / Q000627:therapeutic use*; D006181:H-Reflex / Q000187:drug effects*; D006801:Humans; D009128:Muscle Spasticity / Q000188:drug therapy* / Q000209:etiology / Q000503:physiopathology; D012023:Reflex, Monosynaptic / Q000187:drug effects*; D013119:Spinal Cord Injuries / Q000150:complications* / Q000503:physiopathology
D000316:Adrenergic alpha-Agonists; D003000:Clonidine