Schedule H

Oral

• Capsules 150 mg

• Capsules 300 mg

INDICATIONS + DOSING — FOR CLINICIAN USE ONLY

Primary Indications (Approved / Standard in India)

◾ 1. Duodenal Ulcer

Parameter Recommendation

Starting dose 300 mg once daily at bedtime OR 150 mg twice daily

Titration Not applicable

Usual maintenance dose 150 mg once daily at bedtime (for recurrence prevention)

Maximum dose 300 mg/day

Clinical Notes:

• Treatment duration: 4–8 weeks

• Symptomatic relief often precedes complete mucosal healing; continue full course

• Confirm H. pylori status and treat if positive

◾ 2. Benign Gastric Ulcer

Parameter Recommendation

Starting dose 300 mg once daily at bedtime OR 150 mg twice daily

Titration Not applicable

Usual maintenance dose Not routinely required for gastric ulcers

Maximum dose 300 mg/day

Clinical Notes:

• Treatment duration: 6–8 weeks

• Rule out malignancy before initiating therapy

• Endoscopic confirmation of healing recommended

◾ 3. Gastroesophageal Reflux Disease (GERD)

Parameter Recommendation

Starting dose 150 mg twice daily

Titration May increase to 300 mg twice daily for severe or refractory cases

Usual maintenance dose 150 mg twice daily

Maximum dose 600 mg/day (short-term use only)

Clinical Notes:

• Treatment duration: 8–12 weeks for symptom control

• Less effective than PPIs for erosive esophagitis

• Consider PPI if inadequate response after 4 weeks

◾ 4. Zollinger-Ellison Syndrome (Hypersecretory Conditions)

Parameter Recommendation

Starting dose 150 mg twice daily

Titration Increase by 150 mg increments every 2–3 days based on symptom control and gastric acid output

Usual maintenance dose 300–450 mg/day in divided doses

Maximum dose 600 mg/day

Clinical Notes:

• Specialist supervision required

• PPIs generally preferred; use nizatidine only if PPI-intolerant or contraindicated

• Dose adjustment guided by gastric acid secretion studies

Secondary Indications – Adults (Off-label, if any)

Indication Dose Duration Notes

Functional (non-ulcer) dyspepsia 150 mg twice daily 2–4 weeks trial OFF-LABEL — Limited Indian evidence; consider in cases unresponsive to antacids or prokinetics

PAEDIATRIC DOSING (Specialist Only)

Primary Indications – Paediatric

◾ Duodenal or Gastric Ulcer

Age/Weight Dose Schedule

12 years 150 mg twice daily OR 300 mg at bedtime Adult dosing applies

8–12 years 2.5 mg/kg per dose Twice daily (max 150 mg per dose)

Parameter Recommendation

Starting dose 2.5 mg/kg twice daily (ages 8–12 years)

Titration Not applicable

Usual maintenance dose Same as starting dose

Maximum dose 300 mg/day

Clinical Notes:

• Treatment duration: 4–8 weeks

• Use under gastroenterologist supervision with endoscopy guidance

• Confirm ulcer etiology (H. pylori, NSAID-related)

◾ GERD in Children

Age Recommendation

12 years Adult dosing applies

<12 years Limited evidence; PPIs preferred as first-line therapy

Secondary Indications – Paediatric (Off-label, if any)

Not applicable — No robust off-label indications documented in Indian guidelines

Minimum Age Recommendation:

• Not recommended below 8 years except under specialist supervision

• Capsule formulation limits use in younger children

Safety Monitoring:

• Monitor for CNS effects (agitation, irritability) in younger children

• Adjust dose in adolescents with renal impairment

• Periodic assessment of symptom response

Note: Risk of drug accumulation — monitor for CNS effects (confusion, agitation), especially in elderly patients with renal impairment

• Known hypersensitivity to nizatidine or other H2-receptor antagonists

• History of acute porphyria

• Severe hepatic failure (unless under specialist monitoring)

• Renal impairment — dose adjustment necessary to prevent accumulation

• Elderly patients — increased risk of CNS adverse effects (confusion, agitation, hallucinations)

• Undiagnosed GI symptoms — rule out gastric malignancy before initiating ulcer treatment

• Prolonged therapy (>6 months) — risk of vitamin B12 deficiency

• May mask symptoms of gastric carcinoma — ensure appropriate diagnostic workup in chronic dyspepsia

• Patients on multiple medications — consider pH-dependent drug interactions

Parameter Details

Risk category Limited human data; no definitive evidence of fetal harm in available studies

Preferred alternatives Famotidine may be considered; PPIs (omeprazole, pantoprazole) if acid suppression essential

When may be used Only if clearly needed and benefit outweighs potential risk; avoid high doses

Monitoring Maternal symptom control; fetal growth on routine antenatal scans

Parameter Details

Breastfeeding compatibility Generally compatible; excreted in breast milk in low concentrations

Expected drug levels in milk Low

Preferred alternatives Famotidine (minimal milk excretion) if concern about infant exposure

Infant monitoring Feeding pattern, irritability, GI symptoms (diarrhoea, constipation)

Parameter Recommendation

Starting dose 150 mg once daily

Titration Slower titration; assess renal function before dose escalation

Special risks Increased susceptibility to CNS effects (confusion, hallucinations, agitation); falls; delirium

Additional considerations Assess renal function at baseline and periodically; prefer lower effective dose

Interacting Drug Effect Management

Ketoconazole/Itraconazole Reduced antifungal absorption due to increased gastric pH Avoid combination; if essential, administer antifungal with acidic beverage

Atazanavir Significantly reduced atazanavir absorption (pH-dependent) Avoid co-administration

Rilpivirine Reduced antiretroviral bioavailability Avoid combination

Interacting Drug Effect Management

Warfarin Minor interaction via gastric pH alteration; potential INR fluctuation Monitor INR more frequently during initiation

Theophylline Possible minor effect on clearance Monitor theophylline levels if on high-dose therapy

Iron salts Reduced iron absorption with elevated gastric pH Space doses by 2 hours; monitor for iron deficiency

Antacids May affect nizatidine absorption Space administration by at least 1 hour

Sucralfate Reduced nizatidine absorption Administer nizatidine at least 2 hours before sucralfate

• Headache

• Dizziness

• Fatigue and somnolence

• Diarrhoea or constipation

• Nausea

• Abdominal discomfort

• Sweating

Adverse Effect Clinical Action

Acute interstitial nephritis (rare) Discontinue; nephrology referral

Hepatotoxicity/Drug-induced hepatitis (rare) Discontinue immediately; monitor LFTs

Confusion/Agitation/Hallucinations (especially in elderly or renal impairment) Reduce dose or discontinue

Gynecomastia (rare, reversible) Consider discontinuation; usually resolves after stopping

Anaphylaxis (very rare) Immediate discontinuation; emergency management

Thrombocytopenia (rare) Discontinue; haematology review

Phase Parameters

Baseline Renal function (serum creatinine, eGFR); LFTs if prolonged use anticipated; symptom assessment

After initiation Symptom response at 2–4 weeks; assess for CNS effects in elderly

Long-term (>6 months) CBC periodically; vitamin B12 levels annually; renal function in elderly; reassess need for continued therapy

• Axid® (limited availability)

• Naxid® (Zydus Cadila)

• Nizac® (various manufacturers)

Note: Brand availability may be limited compared to other H2 blockers; verify local availability

Note: Not listed under NLEM; not under NPPA price control

1. Limited use in current practice — PPIs have largely replaced H2 blockers for most acid-related disorders; consider nizatidine mainly in PPI-intolerant patients or for nocturnal acid control adjunct

1. Minimal CYP450 interactions — Advantage over cimetidine in patients on multiple medications; preferable H2 blocker when drug interactions are a concern

1. CNS effects in vulnerable populations — Start low in elderly and renally impaired; confusion and agitation are dose-related and reversible

1. Space pH-dependent medications — Antifungals, iron, and certain antivirals require timing adjustments due to reduced gastric acidity

1. Not effective for nocturnal acid breakthrough — When used with PPIs, H2 blockers may provide temporary benefit but tachyphylaxis develops within 1–2 weeks

1. Rule out malignancy — Symptomatic improvement may mask underlying gastric carcinoma; endoscopy recommended for persistent or alarming symptoms

Nizatidine; H2 blocker; H2 receptor antagonist; acid suppression; peptic ulcer disease; GERD; duodenal ulcer; gastric ulcer; renal-adjustment; elderly-caution; pregnancy-compatible

RxIndia v1.0 — 04 May 2025

• CDSCO (Central Drugs Standard Control Organisation) approved product labels

• IP/NFI (Indian Pharmacopoeia / National Formulary of India 2021)

• API Textbook of Medicine

• Goodman & Gilman's The Pharmacological Basis of Therapeutics

• AIIMS Pharmacology Department Prescribing Guidelines

• Indian hospital protocols from tertiary care centres

• WHO Essential Medicines List (supportive paediatric data)