Effects of effervescent ranitidine on gastric pH: comparison with almagate and placebo in fasting and postprandial conditions.
OBJECTIVE
To compare the effect of effervescent ranitidine, almagate (magnesium carbonate-aluminium hydroxide) and placebo on gastric pH, in fasting and postprandial conditions.


METHODS
Twelve healthy volunteers underwent a gastro-oesophageal pH monitoring on three different occasions after the administration of each of the following randomly allocated treatments: almagate, effervescent ranitidine and placebo. Treatment effects were assessed in fasting and postprandial conditions. Onset and duration of alkalinization, percentage of time with pH > 4 and median gastric pH after treatments were calculated in both periods.


RESULTS
Onset of action of effervescent ranitidine was similar to almagate in fasting [median 1.2 min (IQR: 0.6-12.7) vs. 2.9 min (0.4-227.6)] and postprandial conditions [1.4 min (0.5-4.9) vs. 4.1 min (1.3-63.8)] and both were significantly faster than placebo [fasting 211.1 min (2.7-240); postprandial 240 min (175.6-240)]. The duration of action of effervescent ranitidine was statistically significant longer than almagate in fasting [235 min (105.2-239.4) vs. 19.4 min (6.7-38.8)] and postprandial conditions [171.8 min (133.2-239.5) vs. 61.3 min (44.7-91.9)]. Effervescent ranitidine was more effective than almagate in increasing the percentage of time with a pH > 4 both in fasting (73.9% vs. 7.3%) and postprandial (59.1% vs. 21.3%).


CONCLUSIONS
Effervescent ranitidine shows an effect on gastric pH as fast as almagate but provides a duration of alkalinization longer than almagate, in both fasting and postprandial conditions.
Rey
E
E
Service of Digestive Diseases, Hospital Clínico San Carlos, Madrid, Spain. enrique.rey@erey.net
Poves-Francés
C
C
Sánchez
G
G
Fueyo
A
A
Badiola
C
C
Díaz-Rubio
M
M
D000328:Adult; D000536:Aluminum Hydroxide / Q000494:pharmacology*; D000863:Antacids / Q000494:pharmacology*; D000897:Anti-Ulcer Agents / Q000494:pharmacology*; D002254:Carbonates / Q000494:pharmacology*; D018592:Cross-Over Studies; D005215:Fasting / Q000502:physiology; D005260:Female; D005744:Gastric Acid / Q000502:physiology*; D006801:Humans; D006863:Hydrogen-Ion Concentration; D008276:Magnesium Hydroxide / Q000494:pharmacology*; D008297:Male; D019518:Postprandial Period / Q000502:physiology; D011446:Prospective Studies; D011899:Ranitidine / Q000494:pharmacology*
D000863:Antacids; D000897:Anti-Ulcer Agents; D002254:Carbonates; C043698:almagate; D000536:Aluminum Hydroxide; D011899:Ranitidine; D008276:Magnesium Hydroxide