We conducted a randomised controlled trial to compare the severity of hypotension and ephedrine requirements following spinal anaesthesia for elective caesarean section in women pretreated with either i.v. glycopyrrolate 4.0 mu g/kg (group G) or saline (group S). Data were analysed using sequential analysis which allowed us to terminate the study after data from 40 patients had been analysed (20 in each group). There were no differences between the two groups in the severity of hypotension (mean +/- SD decrease from baseline 35 +/- 14% in group G and 29 +/- 15% in group S) or ephedrine requirements (15 +/- 11 mg in group G and 18 +/- 12 mg in group S). Intra-operative heart rate increased by a greater amount in group G than in group S (58 +/- 26% vs 35 +/- 21% mean +/- SD: P = 0.002) and there was a greater incidence of dry mouth (75% vs 15%; P = 0.0006) but no difference in the incidence of nausea and vomiting (30% vs 50%; P = 0.33). Pretreatment with glycopyrrolate did not confer an advantage in this study. (C) 2000 Harcourt Publishers Ltd.