DESCRIPTION
Nizatidine USP is a histamine H2-receptor antagonist. Chemically, it is N-[2-[[[2-[(dimethylamino)methyl]-4-thiazolyl]methyl]thio]ethyl]-N’-methyl-2-nitro-1,1-ethenediamine.
The structural formula is as follows:
Nizatidine has the molecular formula C12H21N5O2S2 representing a molecular weight of 331.46. It is an off-white to buff crystalline solid that is soluble in water. Nizatidine has a bitter taste and mild sulfur-like odor.
Each capsule for oral administration contains nizatidine 150 mg (0.45 mmol) or 300 mg (0.91 mmol), pregelatinized starch, povidone, corn starch, talc, croscarmellose sodium, dimethicone, gelatin, titanium dioxide, pharmaceutical glaze (modified), synthetic black iron oxide, propylene glycol, FD&C blue #2 aluminum lake, FD&C red #40 aluminum lake, FD&C blue #1 aluminum lake, and D&C yellow #10 aluminum lake. The 150 mg capsule also contains yellow iron oxide, and the 300 mg capsule also contains D&C red #28, FD&C blue #1, and FD&C yellow #6.
CLINICAL PHARMACOLOGY
Nizatidine is a competitive, reversible inhibitor of histamine at the histamine H2-receptors, particularly those in the gastric parietal cells.
Antisecretory Activity
Effects on Acid Secretion
Nizatidine significantly inhibited nocturnal gastric acid secretion for up to 12 hours. Nizatidine also significantly inhibited gastric acid secretion stimulated by food, caffeine, betazole, and pentagastrin (Table 1).
Table 1 Effect of Oral Nizatidine on Gastric Acid Secretion
|
|
Time After Dose (h) |
% Inhibition of Gastric Acid Output by Dose (mg) |
|
|
|
20 - 50 |
75 |
100 |
150 |
300 |
|
Nocturnal |
Up to 10 |
57 |
|
73 |
|
90 |
|
Betazole |
Up to 3 |
|
93 |
|
100 |
99 |
|
Pentagastrin |
Up to 6 |
|
25 |
|
64 |
67 |
|
Meal |
Up to 4 |
41 |
64 |
|
98 |
97 |
|
Caffeine |
Up to 3 |
|
73 |
|
85 |
96 |
Effects on Other Gastrointestinal Secretions
