Nizatidine
Brand names: Axid
Nizatidine is a histamine H2-receptor antagonist used to reduce gastric acid in conditions such as peptic ulcer disease and gastro-oesophageal reflux disease.
Adult dose
Dose adjustments
Reduce the dose in moderate renal impairment (creatinine clearance less than 50 mL/min) and severe renal impairment (creatinine clearance less than 20 mL/min). Duodenal ulcer, benign gastric ulcer and NSAID-associated ulcer: 150 mg in the evening (moderate) or 150 mg on alternate days (severe). Prevention of ulcer recurrence: 150 mg in the evening on alternate days (moderate) or 150 mg in the evening every third day (severe). Gastro-oesophageal reflux disease: from 150 mg daily up to 150 mg twice daily (moderate), or from 150 mg on alternate days up to 150 mg daily (severe). Patients with impaired liver or kidney function should be treated with caution.
Dose auto-extracted from UK Summary of Product Characteristics (SPC) via the eMC; US FDA prescribing information (openFDA / DailyMed) — cross-check; US labelling may differ from UK — not yet clinician-verified. Always confirm against the product SmPC and your local formulary before prescribing.
Contraindications
- Hypersensitivity to the active substance, to any other H2-receptor antagonist, or to any of the excipients
Side effects
- Sweating and urticaria (significantly more common than placebo in large-scale trials)
- Somnolence
- Mild, transient, asymptomatic elevations of transaminases or alkaline phosphatase; hepatitis and jaundice reported, including rare cholestatic or mixed hepatocellular and cholestatic injury
- Rarely: thrombocytopenic purpura, fatal thrombocytopenia, leucopenia, agranulocytosis, anaemia
- Headache and diarrhoea (frequency not known); rare hypersensitivity reactions including bronchospasm, laryngeal oedema, rash, pruritus, eosinophilia, serum sickness and anaphylaxis
Interactions
- No effect on serum levels of concomitantly administered aminophylline, theophylline, chlordiazepoxide, diazepam, lidocaine, phenytoin, ibuprofen, metoprolol, warfarin or lorazepam; nizatidine does not inhibit the hepatic cytochrome P450 drug-metabolising enzyme system
- Salicylates — nizatidine may increase their absorption when used in very high dosage
- Drugs whose absorption is dependent on an acidic gastric pH — nizatidine and other H2-receptor antagonists can reduce their gastric absorption
- Absorption of nizatidine is not clinically significantly affected by food intake, anticholinergic agents or antacids
Clinical monograph
How it works
It competitively blocks histamine H2 receptors on gastric parietal cells, reducing both basal and stimulated gastric acid secretion.
Prescribing in practice
- Exclude gastric malignancy before treatment, as acid suppression can mask the symptoms of gastric cancer.
- Dose adjustment is needed in renal impairment because the drug is largely renally cleared.
- It is generally well tolerated but its acid-lowering effect can alter absorption of pH-dependent medicines.
Monitoring
Routine laboratory monitoring is not usually required, but review symptom response and renal function where relevant.
Counselling the patient
- Advise patients to report persistent or alarm symptoms such as difficulty swallowing, weight loss or vomiting.
- Explain that the medicine reduces stomach acid and that lifestyle measures support reflux control.
Evidence & guidelines
H2-receptor antagonists such as nizatidine are well-established acid-suppressing agents, used in line with current prescribing references and NICE dyspepsia guidance.
Reference: Drug verified in RxNorm (NLM); confirm dosing against the manufacturer SPC (eMC). Verify against your local formulary and current prescribing references before prescribing. The structured dose values shown have been reviewed by a clinician. Monograph status: clinician-reviewed (2026-07-04).
Related
Curated clinical cross-links plus same-class fallbacks.
- Lower Gastrointestinal Bleed · BSG 2019; NICE NG141
- Variceal Upper GI Bleed · BSG 2015; Baveno VII (2022)
- Spontaneous Bacterial Peritonitis (SBP) · BSG / EASL 2018
- Hepatorenal Syndrome · EASL 2018; ICA 2015
- Hepatic Encephalopathy · EASL 2014; West Haven criteria
- Clostridioides difficile Colitis · NICE NG199 (2021); IDSA/SHEA 2021