The effects of atropine and glycopyrrolate on intra-ocular pressure in anaesthetised elderly patients.

The effects of glycopyrrolate 0.2 mg and atropine 0.6 mg, given intravenously, were studied in 40 elderly patients undergoing intra-ocular surgery. Twenty patients had normal intra-ocular pressure (IOP) and 20 had raised IOP. The effects of each of the drugs on IOP, heart rate, prevention of the oculocardiac reflex and incidence of dysrhythmias were assessed. Anaesthesia with thiopentone, suxamethonium, nitrous oxide/oxygen, and halothane, using a semiclosed circle system resulted in a decrease in mean IOP in both the atropine and glycopyrrolate groups. Patients who had pre-existing raised IOP showed a significantly greater decrease in IOP than those with normal IOP. Patients with raised IOP who had received atropine experienced a greater decrease in IOP than those who had received glycopyrrolate. Both atropine and glycopyrrolate were effective in preventing the oculocardiac reflex. The increase in heart rate was greater in those patients who had received atropine. The incidence of dysrhythmias was low.