[Effects of flunitrazepam on intraocular pressure (author's transl)].

Though ophthalmologists operate upon patients that are in a debilitated state, a general anesthesia has to be employed with increasing frequency. Flunitrazepam, known to possess good cardiovascular tolerance, was studied to evaluate its effects on intraocular pressure in 34 unselected patients undergoing 41 operations under general anesthesia, usually 41 operations under general anesthesia, usually for retinal detachment or cataract. Ocular pressure was normal in all cases before surgery, but a history of chronic respiratory insufficiency was obtained in 8 cases and of cardiovascular disease in 18. After premedication with 0.02 mg . kg-1 of flunitrazepam and 0.01 mg . kg-1 of atropine, anesthesia was induced by 0.04 mg . kg-1 i.v. of flunitrazepam alone. No marked alterations in cardiac of respiratory functions were observed. Intraocular pressure was measured with a Schiötz tonometer, just before and 5 minutes after the i.v. injection of flunitrazepam. Results showed -- before: 1.61 +/- 0.51 kPa (12.1 +/- 3.8 mmHg); after: 1.09 +/- 0.36 kPa (8.2 +/- 2.7 mmHg) -- a statistically reduction of 32 p.cent. The precise mechanism of action of flunitrazepam on intraocular pressure is not known, but cannot be related to the reduction in aqueous humor secretory flow or the marked diminution in arterial or venous pressure. A probable explanation is the lowering of resistance to aqueous humor flow exterior to the ocular globe as a result of the muscle relaxant properties of the product. Flunitrazepam appears to be a narcohypnotic of choice in ophthalmological surgery on these inherently debilitated patients.