Double-blind comparison of lidocaine, tubocurarine and diazepam pretreatment in modifying intraocular pressure increases.

One hundred and sixty patients, divided randomly into four groups received normal saline (5 ml), d-tubocurarine (0.05 mg X kg-1), diazepam (0.1 mg X kg-1) or lidocaine (1 mg X kg-1) as pretreatment, in a double blind manner, five minutes before anaesthetic induction with thiopentone and succinylcholine (1 mg X kg-1). Succinylcholine caused a significant increase in IOP in all groups. However, in the lidocaine group, this increase was significantly less than that observed in the control group. The post-succinylcholine increase in IOP was further aggravated by tracheal intubation in all except the lidocaine group. A further clinical trial with higher doses of lidocaine is suggested to assess its ability to obtund the succinylcholine-induced increase in IOP. Lidocaine in a dose of 1 mg X kg-1 IV prevents the rise in IOP which follows intubation.