indication

For the treatment of acid-reflux disorders (GERD), peptic ulcer disease, active benign gastric ulcer, and active duodenal ulcer.

pharmacology

Nizatidine is a competitive, reversible inhibitor of histamine at the histamine H2-receptors, particularly those in the gastric parietal cells. By inhibiting the action of histamine on stomach cells, nizatidine reduces stomach acid production. Nizatidine had no demonstrable antiandrogenic action. Full-dose therapy for the problems treated by nizatidine lasts no longer than 8 weeks. It has been demonstrated that treatment with a reduced dose of nizatidine is effective as maintenance therapy following healing of active duodenal ulcers.

mechanism of action

Nizatidine competes with histamine for binding at the H₂-receptors on the gastric basolateral membrane of parietal cells. Competitive inhibition results in reduction of basal and nocturnal gastric acid secretions. The drug also decreases the gastric acid response to stimuli such as food, caffeine, insulin, betazole, or pentagastrin.

toxicity

Oral, rat LD₅₀: 301 mg/kg. Symptoms of overdose include cholinergic-type effects including lacrimation, salivation, emesis, miosis, and diarrhea.

biotransformation

Hepatic. Less than 7% of an oral dose is metabolized as N2-monodes-methylnizatidine, an H2-receptor antagonist, which is the principal metabolite excreted in the urine. Other likely metabolites are the N2-oxide (less than 5% of the dose) and the S-oxide (less than 6% of the dose).

absorption

Rapid (bioavailability of nizatidine exceeds 70%)

half life

1-2 hours

drug interactions

Atazanavir: This gastric pH modifier decreases the levels/effects of atazanavir

Cefditoren: H2-Antagonists such as nizatidine may decrease the serum concentration of cefditoren. Cefditoren prescribing information recommends to avoid concomitant use with H2-antagonists (eg, famotidine, ranitidine) and antacids as well. Consider alternative methods to minimize/control acid reflux (eg, diet modification) or alternative antimicrobial therapy if use of H2-antagonists can not be avoided.

Enoxacin: Nizatidine may decrease the absorption of enoxacin.

Itraconazole: The H2-receptor antagonist, nizatidine, may decrease the absorption of itraconazole.

Ketoconazole: The H2-receptor antagonist, nizatidine, may decrease the absorption of ketoconazole.