Schedule H

Oral, Intravenous

• Tablets: 20 mg, 40 mg

• Injection: 20 mg/2 mL ampoule (10 mg/mL)

INDICATIONS + DOSING — FOR CLINICIAN USE ONLY

Primary Indications (Approved / Standard in India)

1. Peptic Ulcer Disease (Duodenal and Gastric Ulcers)

Oral Administration:

Parameter Details

Starting dose 40 mg once daily at bedtime

Titration Not routinely required

Usual maintenance dose 20 mg once daily at bedtime

Maximum dose 40 mg twice daily

Duration 4–8 weeks for active ulcer; reassess at 4 weeks

Clinical Notes:

• Bedtime dosing suppresses nocturnal acid secretion effectively

• Healing rates typically 70–80% at 4 weeks, >90% at 8 weeks

1. Gastroesophageal Reflux Disease (GERD)

Oral Administration:

Parameter Details

Starting dose 20 mg orally twice daily

Titration May increase to 40 mg twice daily if inadequate symptom control

Usual maintenance dose 20 mg twice daily

Maximum dose 40 mg twice daily

Duration 6–12 weeks based on symptom response

Clinical Notes:

• Less effective than PPIs for erosive esophagitis

• Suitable for mild-moderate GERD or PPI-intolerant patients

1. Zollinger-Ellison Syndrome

Parameter Details

Starting dose 20 mg orally every 6 hours

Titration Adjust based on gastric acid output and symptom control

Usual maintenance dose 20–40 mg every 6–8 hours

Maximum dose Up to 160 mg every 6 hours (specialist supervision only)

Clinical Notes:

• Higher doses often required compared to standard ulcer therapy

• PPIs generally preferred; famotidine used when PPIs not tolerated

1. Stress Ulcer Prophylaxis (ICU Setting)

Intravenous Administration:

Parameter Details

Starting dose 20 mg IV every 12 hours

Titration Not applicable

Usual maintenance dose 20 mg IV every 12 hours

Maximum dose 20 mg IV every 8 hours (select protocols)

Duration Duration of ICU stay; typically ≤14 days

Clinical Notes:

• Used when oral route not feasible

• Transition to oral therapy when patient can take orally

• Consider infection risk with prolonged acid suppression

Secondary Indications — Adults Only (Off-label)

Indication Dose Duration Remarks

NSAID-associated dyspepsia — OFF-LABEL 20 mg once or twice daily As needed Specialist supervision; Indian clinical practice

Chronic urticaria (adjunct to H1-antihistamines) — OFF-LABEL 20 mg orally twice daily Short-term; reassess at 4 weeks Specialist only (Dermatologist); based on H2-blocker add-on therapy evidence

PAEDIATRIC DOSING (Specialist Only)

Primary Indications

1. GERD and Peptic Ulcer Disease (Age ≥1 month)

Oral Dosing:

1–12 months 0.5 mg/kg/dose twice daily Based on symptom response 0.5 mg/kg/dose twice daily 1 mg/kg/day

1–16 years 0.5 mg/kg/dose twice daily May increase based on response 0.5–1 mg/kg/dose twice daily 40 mg/day

Duration: 4–8 weeks

Intravenous Dosing (Hospitalised Patients):

≥1 month 0.25–0.5 mg/kg/dose Every 12 hours 20 mg/day

Monitoring:

• Clinical symptom response

• Signs of acid over-suppression

• Stool consistency (diarrhoea)

Secondary Indications — Paediatric (Off-label)

Indication Dose Duration Remarks

Stress ulcer prophylaxis in PICU — OFF-LABEL 0.25 mg/kg IV every 12 hours Duration of PICU stay Specialist only; Indian PICU protocols; monitor for nosocomial infections

⚠️ Not recommended below 1 month of age except under neonatologist supervision with documented justification.

CrCl (mL/min) Dose Adjustment

50 No adjustment required

30–50 Reduce dose by 50% OR extend interval to once daily

10–30 20 mg once daily or 50% of standard dose

<10 20 mg every 36–48 hours based on clinical response

Haemodialysis Administer after dialysis session; not significantly removed by dialysis

Peritoneal dialysis Dose as for CrCl <10 mL/min

• Known hypersensitivity to famotidine or other H2-receptor antagonists (ranitidine, cimetidine)

• Acute porphyria

• Renal impairment — dose adjustment required to prevent accumulation

• Elderly patients — higher risk of CNS effects (confusion, delirium)

• Long-term use (>6 months) — risk of vitamin B12 deficiency, hypomagnesaemia

• May mask symptoms of gastric malignancy — endoscopic evaluation recommended before initiating therapy in patients with alarm features (weight loss, dysphagia, GI bleeding)

• Concurrent use of pH-dependent drugs — may affect absorption

Parameter Details

Safety Category Limited human data; generally considered safe (compatible with use)

Preferred alternatives Famotidine is preferred H2 blocker in Indian obstetric practice

When to use May be used when clinically indicated for GERD or peptic ulcer

Monitoring Maternal symptom control; reassess continued need periodically

Parameter Details

Compatibility Compatible with breastfeeding

Drug levels in milk Low (concentrated in breastmilk but infant dose remains low)

Preferred alternatives Famotidine acceptable; no preferred alternative needed

Infant monitoring GI symptoms (loose stools, irritability) if prolonged maternal use

Parameter Recommendation

Starting dose 20 mg once daily

Titration Cautious; slower titration recommended

Special considerations Assess renal function before dosing; higher risk of CNS adverse effects (confusion, disorientation, hallucinations); increased falls risk due to dizziness

Additional precautions Avoid long-term high-dose use without periodic reassessment; monitor for B12 deficiency

Drug Mechanism Clinical Effect Recommendation

Atazanavir Increased gastric pH reduces atazanavir solubility Markedly decreased atazanavir absorption and efficacy Avoid combination; if essential, separate by ≥12 hours and use atazanavir with ritonavir

Rilpivirine pH-dependent absorption Profound reduction in rilpivirine levels Contraindicated — do not co-administer

Dasatinib Requires acidic pH for absorption Significantly reduced dasatinib efficacy Avoid H2 blockers; if unavoidable, administer dasatinib ≥2 hours before famotidine

Erlotinib pH-dependent absorption Reduced erlotinib levels Avoid concurrent use

Drug Interaction Recommendation

Ketoconazole, Itraconazole Reduced absorption due to elevated gastric pH Administer antifungal ≥2 hours before famotidine

Iron supplements Decreased iron absorption Separate dosing; consider ascorbic acid to enhance absorption

Warfarin Rare reports of altered INR Monitor INR closely during initiation and dose changes

Cefuroxime axetil, Cefpodoxime Reduced absorption with elevated gastric pH Monitor for treatment failure

CNS depressants Additive CNS effects in susceptible patients Use caution in elderly

• Headache

• Dizziness

• Constipation

• Diarrhoea

• Fatigue

• Nausea

• Dry mouth

• CNS effects — Confusion, hallucinations, agitation, delirium (particularly in elderly or renally impaired) — discontinue and evaluate

• Agranulocytosis, thrombocytopenia — Rare; discontinue immediately if suspected

• QT prolongation — Rare; caution in patients with pre-existing QT prolongation or on other QT-prolonging drugs

• Pancreatitis — Very rare

• Severe hypersensitivity reactions — Anaphylaxis, angioedema; discontinue immediately

Phase Parameters

Baseline Renal function (serum creatinine, eGFR); symptom assessment; consider endoscopy if alarm features present

During treatment Symptom response at 2–4 weeks; reassess need for continued therapy

Long-term use (>6 months) Renal function; serum magnesium; vitamin B12 levels; periodic reassessment of indication

IV administration Injection site monitoring; vital signs

• Famocid® (Sun Pharma)

• Famonext® (Zydus Cadila)

• Famotag® (Cipla)

• Pepcia® (Aristo)

• Topcid® (Dr. Reddy's)

• Facid® (Intas)

Note: Available in FDCs with antacids (domperidone combinations available for OTC use in lower doses).

Note: Not included in NLEM 2022; not NPPA price-controlled.

• H2 blocker of choice: Famotidine preferred over cimetidine due to fewer drug interactions and lower CNS side effect profile

• Nocturnal acid control: Bedtime dosing particularly effective for nocturnal acid breakthrough when used with PPIs

• Pregnancy safety: Preferred H2 blocker during pregnancy in Indian obstetric practice

• Renal impairment: Always adjust dose in CKD — accumulation leads to CNS toxicity, especially in elderly

• Tachyphylaxis: Tolerance develops with continuous use; intermittent or on-demand dosing may be preferred for long-term symptom control

• H. pylori evaluation: Test for H. pylori infection in recurrent peptic ulcer disease despite adequate acid suppression

acid suppression; H2 blocker; GERD; peptic ulcer; stress ulcer prophylaxis; renal adjustment; pregnancy-safe; elderly-caution; Schedule H; India

RxIndia v1.0 — 09 Apr 2025

• CDSCO approved prescribing information

• Indian Pharmacopoeia

• API Textbook of Medicine — Acid Peptic Disease

• AIIMS Drug Formulary

• IAP Textbook of Pediatrics — Gastrointestinal Disorders

• Indian ICU protocols for stress ulcer prophylaxis

• Harrison's Principles of Internal Medicine

• Goodman & Gilman's The Pharmacological Basis of Therapeutics