This paper reviews the behaviour of intraocular pressure (IOP) in glaucomatous eyes treated with
metipranolol with and without
drug-induced adverse reactions (ADRs). Two hundred and forty seven patients with
open angle glaucoma who were receiving the three different strengths of
metipranolol (0.1%, 0.3%, and 0.6%) in our Department and the 7 patients who participated in the
metipranolol rechallenge trial were included in this study. Out of the 247 patients, there were 52 eyes of 29 patients who showed 78 episodes of ADRs associated with
metipranolol. Forty five of these 78 episodes (57.6%) were associated with loss of IOP control. Two of the 7 eyes treated with
metipranolol in the rechallenge trial showed loss of IOP control, 1 of them without any signs of ocular
inflammation. We further studied all the glaucomatous eyes controlled with
metipranolol 0.6% only and 22 eyes were identified with loss of IOP control but without recognisable signs or symptoms of ADR. Five other eyes in this group later developed
metipranolol-induced ADRs. The possible pathophysiological mechanisms for the loss of IOP control are discussed and it is suggested that the active
drug,
metipranolol, could be directly implicated.