Table 1 Percentages of time with gastric pH above 3 and 4, and gastric acid concentrations for the 24-hour, diurnal and nocturnal periods following a single dose of placebo, 20 mg omeprazole (O) or 20 mg rabeprazole (R) in 18 obese volunteers

% time above pH3

• 24-hour period

46.5 (37.3-54.9)

29.7 (15.2-55.5)

8.8 (4.8-10.8)

0.10

• Diurnal period

52.1 (36.4-67.8)

32.3 (14.9-64.0)

10.2 (6.2-15.1)

0.08

• Nocturnal period

38.2 (24.2-56.6)

29.5 (6.7-49.2)

4.1 (1.9-13.2)

0.25

% time above pH4

• 24-hour period

33.4 (27.2-44.3)

21.3 (10 .1-38.9)

5.3 (2.5-8.2)

0.24

• Diurnal period

37.9 (25.1-49.7)

20.1 (9.8-48.6)

4.6 (1.8-8.5)

0.21

• Nocturnal period

27.7 (14.0-49.3)

20.1 (3.3-37.4)

3.1 (0.2-10.6)

0.46

Acid concentration [H ⁺ ] mmol/l

• 24-hour period

22 (14–53)

54 (19–130)

95 (73–170)

0.01

• Diurnal period

27 (9–57)

53 (10–81)

97 (64–150)

0.05

• Nocturnal period

29 (18–48)

57 (23–160)

115(76–180)

0.01