Low dose famotidine and cimetidine in single postprandial doses: a placebo controlled comparative study of overnight pH.

Abstract

To investigate the relative abilities of low doses of famotidine and cimetidine to raise intragastric pH after a single postprandial evening dose, 16 healthy volunteers were recruited to a four period crossover trial of famotidine 10 mg, cimetidine 100 mg and 200 mg compared with placebo. Intragastric pH was monitored between 1800 and 0730 with a nasogastric pH electrode. Median gastric pH rose from 1.35 (interquartile range 1-1-1-65) with placebo to 1 95 (1.6-5.35, p<O.OOl Friedman rank) after dosing with famotidine 10 mg, to 1.46 (1.3-2.0, 0.05<p<0.1) after cimetidine 200 mg, and remained 1.35 (1-1-1.6, p>0.2) after cimetidine 100 mg. Intragastric pH was above 3 for 34% (p<0.005) of the time after dosing with famotidine, compared with 13.6% (p>0.2) after cimetidine 200 mg, 9.5% (p>02) after cimetidine 100 mg, and 4.7% after placebo. The rise of intragastric pH after famotidine 10 mg is significantly greater than that after either 200 mg or 100 mg cimetidine when the drugs are used postprandially. (Gut 1995; 37: 325-328) Keywords: H2 receptor antagonist, intragastric pH, famotidine, cimetidine. Study designThe investigation was designed as a four period crossover study with all subjects receiving the four different preparations in a random order. The study was partially blinded in that the drugs were recognisably different but the subjects were not aware of which was which. Of the two principal investigators one (RPW) was blinded to the drugs. There was a wash out period of at least six days between studies.On each study day subjects arrived at 1700 on the investigation unit having fasted for six hours. Bipolar glass pH electrodes (Ingold M440) were calibrated in standard buffer solutions of pH 7.00 and 4.01 and calibration was verified at pH 1.69. These electrodes were passed by the nasogastric route. A drop in pH to less than 2 was taken as evidence of the tip of the probe having entered the stomach, and the electrode was advanced a further 8 cm from this point. At 1830 a standard meal was given, which consisted of a supermarket ready meal of cottage pie, peas, and carrots, followed by chocolate coated ice cream and two chocolate mints to give a total of 700 kcal, provided by 22 g protein, 70 g carbohydrate, and 37 g fat, accompanied by 250 ml mineral water.

Control of intragastric acidity with over‐the‐counter doses of ranitidine or famotidine

“…In this study, the gastric acid inhibitory effect of ranitidine, 75 mg, and famotidine, 10 mg, taken around midday, persisted even in the overnight period. Overall, the effects of ranitidine and famotidine were similar and consistent with previous studies which have evaluated low doses of famotidine and ranitidine 3–6 , . 16 However, it is uncertain whether this late and modest effect can translate into symptomatic benefit for patients.…”

“…Several studies have compared the onset and duration of action of ranitidine, famotidine and cimetidine on intragastric acidity using the model of 24‐h acidity 3–6 . This model was designed for the study of the effect of these drugs on gastric acidity by attempting to simulate normal everyday activity.…”

Comparison of the effect of the antacid Rennie versus low‐dose H2‐receptor antagonists (ranitidine, famotidine) on intragastric acidity

“…The introduction of low doses of H 2 ‐antagonists as OTC treatments for nocturnal heartburn and dyspepsia offers a potential solution to this problem, because of their long duration of action 16 , . 17 So far, no studies exist comparing these two medication groups at OTC dosages for patients with nocturnal heartburn.…”

Impact of food intake on the antisecretory effect of low‐dose ranitidine and famotidine

“…Earlier studies have, however, demonstrated that at over-the-counter doses, cimetidine has a slightly lower antisecretory ef®cacy than famotidine and ranitidine. 9,11 On the other hand, a new effervescent preparation of 200 mg cimetidine has been shown to induce a more rapid suppressive effect on intragastric acidity than ®lm-coated tablets of famotidine. 31 This is likely to induce a more rapid symptom relief during the daytime.…”

“…Studies comparing the efficacy of the H 2 ‐antagonists at over‐the‐counter dosage were usually performed either in fasting or postprandial subjects 6 –11 . It is well known that meal intake reduces the acid inhibitory effect of high dose H 2 ‐antagonists 12 –14 .…”