Purpose:
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.
Results:
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.
Conclusion:
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.