Actions of tizanidine on alpha 1-and alpha 2-adrenoceptors in the peripheral tissues

Tizanidine behaved as the partial agonist on the alpha 1-adrenoceptor in high doses (10(-6) -10(-4)M) and as the alpha 2-adrenoceptor agonist in low doses (3 X 10(-9) - 10(-6)M). Tizanidine is about one-third as potent as clonidine in alpha 2-agonistic effect