Antimuscarinic Action of Oxymetazoline on Human Intraocular Muscles

Abstract

At 10 μM or 100 μM concentration of oxymetazoline, the activity of carbachol was competitively blocked on the isolated human iris sphincter or ciliary muscles. On the ciliary muscle, the dissociation constant K_B of 5.2 μM was obtained. The value is approximately equal to that on the iris sphincter. Even though it is a weakly active antimuscarinic drug with potent α-adrenoceptor–mediated vasoconstriction activity, the therapeutic benefit in ocular decongestion recovery may be partly related to the weak anticholinergic activity.