Twenty four hour intragastric acidity and plasma gastrin concentration in healthy volunteers taking nizatidine 150 mg, nizatidine 300 mg, ranitidine 300 mg, or placebo at 21:00 h.
Nine healthy volunteers were studied on the seventh day of dosing at 21:00 h with nizatidine 150 mg (N 150), nizatidine 300 mg (N 300), ranitidine 300 mg (R 300), or placebo, given in a predetermined random order. The double-blind 24 hour studies, using the Royal Free Hospital standard protocol, simultaneously measured intragastric acidity and plasma gastrin concentration. Compared with placebo, subjects responded to dosing with each H2-antagonist by a significant decrease of 24 hour intragastric acidity (N 150-45%; N 300-49% R 300-56%; p less than 0.01) and a significant rise of plasma gastrin concentration (N 150 + 20%; N 300 + 27%; R 300 + 58%; p less than 0.01). All three drug regimens caused similar significant decreases of nocturnal acidity (N 150-72%; N 300-79%; R 300-85%; p less than 0.01) and increases of nocturnal plasma gastrin concentration (N 150 + 41%; N300 + 52%; R 300 + 80%; p less than 0.01). Dosing with ranitidine 300 mg at 21:00 h also caused a simultaneous significant decrease of morning acidity (-32%; p less than 0.05) with a significant increase of plasma gastrin concentration (+36%; p less than 0.05), but the antisecretory effects of nizatidine 150 or 300 mg at 21:00 h were only observed during the night, with no effect during the morning. No drug regimen had any effect on acidity or plasma gastrin in the afternoon or early evening.
Lanzon-Miller
S
S
Academic Department of Medicine, Royal Free Hospital School of Medicine, London.
Pounder
R E
RE
Chronos
N A
NA
Raymond
F
F
Hamilton
M R
MR
Dalgleish
D
D
D000328:Adult; D005744:Gastric Acid / Q000378:metabolism*; D005745:Gastric Acidity Determination; D005755:Gastrins / Q000097:blood*; D006635:Histamine H2 Antagonists / Q000494:pharmacology*; D006801:Humans; D008297:Male; D016567:Nizatidine; D011899:Ranitidine / Q000494:pharmacology*; D013844:Thiazoles / Q000494:pharmacology*; D013997:Time Factors
D005755:Gastrins; D006635:Histamine H2 Antagonists; D013844:Thiazoles; D011899:Ranitidine; D016567:Nizatidine