[Experimental study on ocular hypotensive efficacy of parenteral metoprolol]

to evaluate ocular hypotensive efficacy of parenteral metoprolol in an experiment.

A total of 3 series of experiments on 24 rabbits were performed. The first series involved a single subconjunctival injection of 0.3 mg of metoprolol in the right eye, while the left served as a control. During the second series the rabbits received 0.5 mg of metoprolol intramuscularly. The third series also implied a subconjunctival injection of 0.3 mg of metoprolol in the right eye, however, supplemented with timolol 0.5% instilled in the left. In all rabbits tonometry was performed before the injection and then in 30 min, 1, 2, 3, 6, 8, and 24 hours. Biomicroscopy and ophthalmoscopy were also performed before and 1, 3, and 7 days after the injection.

The maximum reduction (down to 30% from the baseline) of intraocular pressure (IOP) was registered in intramuscular metoprolol rabbits. Subconjunctival metoprolol was associated with a faster and more pronounced decrease in IOP as compared to timolol instillations. In case of local or systemic parenteral administration the hypotensive effect of metoprolol lasts for more than a day.