Antroduodenal motility and gastric emptying. Gastroduodenal motility and pH following ingestion of paracetamol

The influence of paracetamol on antroduodenal motility and gastric pH was studied in 11 healthy subjects and the relationship between gastroduodenal motility and gastric emptying rate time, tmax, to peak concentration of serum paracetamol, Cmax, was evaluated. The incidence of antral phase III activity and the duration of phase III was diminished with paracetamol (P less than 0.05). The other motility parameters assessed were unchanged. Three patterns of motility and absorption were observed. One group (n = 5) were fast absorbers with a tmax of 1 h and a motility pattern characterized by antral activity, a high motility index and a short duration of phase II (33-60 min); the phase IIIs were complete except in one case. The second group (n = 4) had tmax at 1.5 h and their phase II motility was characterized by a longer duration (80-133 min) (P less than 0.05), by antral activity, and by a high motility index; their phase IIIs were all incomplete. The last group (n = 2) were slow absorbers: Cmax was not reached in the investigation period, no antral contractions were seen, and the motility index was low. The area under the serum-concentration curve of paracetamol differed between the groups at 90 and 180 min (P less than 0.01).