The pharmacological effects of selective alpha 1 blockers on the prostate are well studied, however regulatory effects of adrenoreceptor on the intraocular pressure (IOP) and iris smooth muscle are not apparent . Here in we aimed to assess the acute effect of oral alpha 1 antagonist on the IOP in rabbits eye.
Material and Methods:
Oral selective Alpha 1 blocker (doxasozin) was given for 4 rabbits and 2 rabbits were used as control group. The daily dose of doxasozin was 0.08 mg/kg and it was given orally via injector after dissolving the drug in isotonic solution. The IOP of right and left eyes were measured immediately before and 2 hours after therapy for each rabbit. The IOP for the rabbits in the control group was also measured at the same times. Local anesthetic eye drops, oxybuprocaine hydrochloride 0.4% (Localin), was used before measuring IOP. Ten observations for each rabbit were done. All observations were done at intervals separated by one week to wash out the previous drug.
The mean values of IOP for the right eye before and after therapy were 13.62+ 3.82 and 11.08 +4.59 mmHg respectively (p=0.002). The mean values of IOP of the left eye before and after therapy were 13.08+4.15 and 10.13+ 4.4 mmHg respectively (p=0.005). The average percentage of reduction in the IOP of the right and left eyes were 34.49% and 39.29% respectively and no significant difference between both eyes were detected( p=0.31). Out of 40 observations for the IOP for the right eye, 27 (67%) of them had showed reduction in the IOP, 6 (15%)showed no change in IOP and 7 (16%) of them showed increments in the IOP. Out of 40 observations for the IOP of the left eye, 29(73%) of them showed reduction in the IOP, 3 (7.5%)showed no change and 8 (20%)showed increment in IOP. The control group showed no significant variation in the IOP neither in the right nor in the left eye, p=0.7, p=0.13 respectively.
Oral alpha 1 adrenergic antagonists result in a significant acute reduction in IOP in rabbits eye. Giving alpha 1 blocker for patients with high IOP may be beneficial. Further studies in vitro and vivo should be carried out with large numbers of cases to confirm our results.