Nizatidine

Nizatidine is a histamine H2 receptor antagonist used to decrease gastric acid production. It is indicated for the treatment and prevention of peptic ulcers (duodenal and gastric), gastroesophageal reflux disease (GERD) and erosive esophagitis, and may be used for gastritis, dyspepsia, and NSAID-associated ulcers. It is available in oral form and, less commonly, as an injectable, and has been marketed under the brand name Axid; generic versions are available in some regions.

Mechanism of action: Nizatidine competitively inhibits histamine at H2 receptors on gastric parietal cells, reducing basal and nocturnal acid secretion and elevating gastric pH. This acid-suppressive effect facilitates healing of ulcers and improves GERD symptoms.

Pharmacokinetics and dosing: After oral administration, nizatidine is absorbed with peak plasma concentrations in about 1 to 3 hours. The elimination half-life is around 1.5 to 2.5 hours, and most of the drug is excreted unchanged in urine. Renal impairment requires dose adjustment. Adult regimens typically involve divided doses, tailored to the condition and patient factors.

Adverse effects and safety: Nizatidine is generally well tolerated. Common adverse effects include headache, dizziness, abdominal discomfort or diarrhea, and fatigue. Rare serious reactions include hypersensitivity, elevations in liver enzymes, and confusion in the elderly; caution is advised in renal impairment. Drug interactions mainly concern absorption—antacids or other orally administered drugs may have altered absorption when given with nizatidine. Pregnancy category varies by region; consult local guidelines.

History and regulation: Developed as part of the H2 blocker class in the late 20th century for peptic ulcers and GERD. Availability varies by country; many markets have shifted to newer agents, but the drug remains in use in some regions.