Effect of prazosin on aqueous humor dynamics in rabbits
T. Krupin, M. Feitl and B. Becker
Prazosin hydrochloride, a systemic antihypertensive agent, lowers
intraocular pressure when applied topically to normal rabbit eyes. A 0.01%
solution of topically administered prazosin did not alter out-flow
facility, episcleral venous pressure, systemic blood pressure, or ocular
blood flow. Tonography suggested a 27% decrease in the rate of aqueous
humor formation two hours following topical administration. Posterior
chamber aqueous ascorbate levels were increased following topical
administration of prazosin, which also suggested a decreased entry rate of
water into the eye. The effect of prazosin on IOP was prevented by systemic
pretreatment with phentolamine mesylate, an alpha-adrenergic blocking
agent, but not by propranolol hydrochloride or atropine sulfate. This was
consistent with the known action of prazosin as a postsynaptic
alpha-adrenergic blocking agent.
