A comparison of clonidine, cyproheptadine and baclofen in spastic spinal cord injured patients.

In twenty-five SCI subjects, antispasticity effects of three putative antispasticity agents [clonidine (an alpha-2 noradrenergic agonist), cyproheptadine (a 5-HT2 antagonist) and baclofen (a GABA-B agonist)] were tested in terms of changes in leg tone as graded by the Ashworth scale (AS), in terms of the vibratory inhibition of the H-reflex (VII) and in terms of the ability of the knee to swing passively in the pendulum test as quantified by video motion analysis. When compared to the no drug period, all three drug treatments showed an antispasticity effect on the AS, the VII and the amplitude of the first swing and the relaxation index of the pendulum test, p. < 0001. Surprisingly, cyproheptadine and baclofen produced a greater reduction in the VII than clonidine, p. < 01. The amplitude of the first swing in the pendulum test correlated well with the AS, r = .88, and the antispasticity effects of the drugs produced improvements in both measures, a reduced AS and increased amplitude of knee swing in the pendulum test. Therefore, video motion analysis of the pendulum test is as valid a measure of spasticity as the Ashworth scale and is not limited by subjectivity of the examiner.