SHORT-TERM EFFECT OF CAPTOPRIL ON INTRAOCULAR PRESSURE

The angiotensin converting enzyme (ACE), which is responsible for the conversion of angiotensin-I to angiotensin-II, and metabolism of bradykinin is found to be present in human ocular tissue and it manifests a variety of physiological and pharmacological effects. Angiotensin increased the intraocular pressure (IOP) in animals. Even, the topical instillation of ACE inhibitors have been reported to reduce the IOP in rabbits. We, therefore performed this randomized, double masked, parallel groups-design and placebo controlled study, to investigate the acute effect of captopril (6.25 mg, 12.50 mg, and 25.00 mg) and placebo on IOP, systolic blood pressure (SBP), diastolic blood pressure (DBP) and heart rate in healthy human volunteers. These parameters were monitored for 4.0 h after the administration of drugs. Captopril 12.50 mg and 25.00 mg significantly reduced the IOP and SBP (P < 0.05). Captopril 6.25 mg also had a tendency to lower the IOP and significantly decreased the SBP (P < 0.05). The mechanism involved in the decrease of IOP and blood pressure with captopril could be due to inhibition in the formation of angiotensin-II and sparing of bradykinin.