Effects of the 5-HT3 receptor antagonist, ICS 205-930, on oesophageal motor activity and on lower oesophageal sphincter pressure: a double-blind cross-over study.

The selective 5-HT3 receptor antagonist, ICS 205-930 (Sandoz), has potent effects on gastrointestinal motor activity in vitro and in vivo. This double-blind, crossover study compared the effects of 20 mg of ICS 205-930 infused intravenously with those of a placebo on the motor activity of the oesophageal body and the lower oesophageal sphincter (LOS). Each of twelve healthy young men participated in two recording sessions one week apart. Oesophageal pressures were recorded using a catheter assembly with orifices 2, 5, 8, 11, and 14 cm above the oral border of the LOS and a Dent sleeve for measurement within the LOS. During and after the infusion of ICS 205-930, amplitude and duration of swallow-initiated contractions in the smooth muscle oesophagus increased slightly, the area under the curve as a measure of contraction strength being significantly greater than after placebo (P less than 0.05). LOS resting pressure increased slightly during ICS 205-930 infusion and was significantly higher than it was in the case of the placebo (P less than 0.001). Propagation velocity of contractions, incidence of tertiary contractions and relaxation of LOS upon swallowing remained unaffected. ICS 205-930 was well tolerated. It is concluded that ICS 205-930 has slight but distinct stimulatory effects on contraction strength in the smooth muscle oesophagus and LOS resting pressure.