Nocturnal intragastric acidity after over-the-counter doses of famotidine, ranitidine or placebo.
OBJECTIVE
To compare the inhibitory effects of over-the-counter doses of famotidine or ranitidine on nocturnal intragastric acidity in a placebo-controlled study.


METHODS
Twelve-hour intragastric acidity was measured simultaneously in 24 healthy subjects who ate a standard meal at 18.30 h and were dosed (at 19.30 h) with either famotidine 10 mg, ranitidine 75 mg or placebo in a balanced three-period crossover design. Five-millilitre aliquots of gastric juice were aspirated half-hourly 0-3 h post-dose, and then hourly until the end of the study. pH was measured with a glass electrode. Integrated pH (area under the curve (AUC) of the pH-time curve) was calculated for the intervals 0-12 h and 9-12 h post-dose. Statistical analysis was by ANOVA.


RESULTS
In the 0-12 h post-dose period, when the 24 subjects were dosed with placebo, mean AUC was 2.12, increasing by 75% to 3.70 with famotidine (P < 0.001) and by 81% to 3.83 with ranitidine (P < 0.001). In the 9-12 h post-dose period, when the subjects were dosed with placebo, mean AUC was 2.13, increasing by 91% to 4.07 with famotidine (P < 0.001) and by 79% to 3.82 with ranitidine (P < 0.001). There was no significant difference between the pH-raising effects of famotidine and ranitidine in both periods.


CONCLUSIONS
Famotidine and ranitidine in over-the-counter doses have a similar, sustained, effect on post-prandial nocturnal intragastric acidity in healthy subjects lasting up to 12 h after oral dosing.
Grimley
C E
CE
Department of Gastroenterology, Walsgrave Hospital, Coventry, UK.
Cottrell
J
J
Mann
S G
SG
Stauffer
L
L
Nwokolo
C U
CU
D000328:Adult; D018592:Cross-Over Studies; D015738:Famotidine / Q000494:pharmacology*; D005260:Female; D005744:Gastric Acid / Q000378:metabolism*; D005753:Gastric Mucosa / Q000187:drug effects* / Q000378:metabolism; D006635:Histamine H2 Antagonists / Q000494:pharmacology*; D006801:Humans; D006863:Hydrogen-Ion Concentration; D008297:Male; D008875:Middle Aged; D004366:Nonprescription Drugs / Q000494:pharmacology*; D011899:Ranitidine / Q000494:pharmacology*; D013997:Time Factors
D006635:Histamine H2 Antagonists; D004366:Nonprescription Drugs; D015738:Famotidine; D011899:Ranitidine