Influence of topically applied prazosin on the intraocular pressure of experimental animals
B. R. Smith, D. L. Murray and I. H. Leopold
Prazosin hydrochloride, an oral antihypertensive, is reported to inhibit
phosphodiesterase and block postsynaptic alpha-adrenergic receptors,
intraocular pressure (IOP) in rabbits was reduced in a dose-related manner
following topical ocular application of concentrations of 0.0001% to 0.1%.
The ocular hypotensive response lasted six to eight hours with a maximum
effect at approximately two hours. The IOP of unilaterally sympathectomized
rabbits treated in both eyes with prazosin decreased more in the normal
eyes than in the sympathectomized eyes. Treatment of only the
unsympathectomized eyes of these rabbits elicited a similar response.
Normal rabbits elicited a similar response. Normal rabbits treated in only
one eye also showed a slight response in the contralateral eye. Preliminary
experiments did not support the hypothesis that these effects were due to a
decrease of systemic blood pressure. No substantial ocular toxicity or
pupillary changes were observed.
