Dihydrolevobunolol is a potent ocular beta-adrenoceptor antagonist

The ocular beta-adrenoceptor antagonist activity of dihydrolevobunolol (DHLB), the major ocular and systemic metabolite of levobunolol was investigated by determining its ability to block isoproterenol-induced ocular hypotension in normotensive rabbits. Topically-applied 0.001% and 0.01% DHLB virtually abolished the response to isoproterenol, indicating a beta-blocking potency similar to that of timolol. Thus, the ocular metabolism of levobunolol leads to the formation of a highly potent beta-adrenoceptor antagonist that may contribute to its clinical efficacy.