Reduction of spastic hypertonia in patients with spinal cord injury: A double-blind comparison of intravenous orphenadrine citrate and placebo

Spasticity is one of the major problems affecting the outcome of rehabilitation in paraplegic patients. Orphenadrine citrate possesses an effective muscle relaxant action in many pathologies. Nevertheless, despite a recognized central site of action, no controlled data are available on its use in the treatment of spastic hypertonia in patients with spinal cord injuries. Therefore, the effect of intravenous administration of 60mg of orphenadrine citrate versus placebo on spastic hypertonia after spinal cord injury was studied in 11 patients. The threshold of the flexion reflex of the lower limb was studied as a neurophysiological correlate of spastic hypertonia. Clinical assessment was made using the Ashworth Spasticity Scale. The threshold, expressed in mAmp, was studied for 60 minutes after the treatment. A significant difference was found using the active drug compared with placebo ( p < 0.0001). In 9 patients, the reduction of the abnormal flexion responses after orphenadrine appeared to begin only after 30 minutes. In one patient the onset of the therapeutic effect was early but weak. One patient with severe spastic hypertonia leading to triple flexion when the limb was manipulated did not gain any relief with orphenadrine. The clinical and neurophysiological results suggest an efficacy of orphenadrine citrate in the control of spastic hypertonia in paraplegics. This could be relevant in the rehabilitation strategy, although further studies are needed on the duration of its action.