Clinical beta

FMBM is currently in clinical beta. Content is for professional review/testing and must not replace local protocols, senior clinical judgment, or official prescribing references.

Drug Monograph

Famotidine

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USE IF: GERD/dyspepsia; selected PUD; stress ulcer prophylaxis in chosen inpatient pathways; nocturnal symptoms; PPI alternative when appropriate — with renal dosing and realistic potency vs PPI for severe disease.

AVOID IF: Expecting PPI-equivalent suppression for major UGI bleed or severe erosive esophagitis as sole therapy; continuing indefinitely without indication; ignoring renal dose adjustment or red-flag GI symptoms.

Famotidine

H2 receptor antagonist (acid suppression)

AdultGERDGIPUDICUWardClinicRenal

Indication

GERD / dyspepsia • Selected PUD • SUP (selected) • Nocturnal symptoms • PPI-sparing when appropriate

At a glance

INDICATIONS (CORE USE)

- GERD / dyspepsia - Peptic ulcer disease (selected contexts) - Stress ulcer prophylaxis (selected inpatient contexts) - PPI alternative when not preferred / not tolerated - Nocturnal acid suppression

ADULT DOSE (STANDARD)

Typical PO: 20 mg BID or 40 mg daily (indication-dependent) IV: protocol-based for inpatient use Adjust for renal function

MAX DOSE

Avoid oversimplified universal max — prioritize renal dose adjustment and indication-appropriate duration

Route

PO / IV

PEDIATRIC DOSE

Weight-based / protocol-driven only

Do not miss

Must-not-miss safety points

Major warning

- Renal impairment → accumulation risk; dose reduction required - CNS effects can occur in elderly / renal dysfunction (confusion, agitation) - H2 blockers are weaker than PPIs for severe acid-related disease / GI bleed protocols - Long-term casual continuation without indication should still be reassessed - Do not let symptomatic relief delay evaluation of serious GI pathology

Indications

Primary

  • GERD / dyspepsia
  • Peptic ulcer disease (selected contexts)
  • Stress ulcer prophylaxis (selected inpatient contexts)

Secondary

  • Histamine-mediated symptom adjunct (selected allergy/urticaria protocols)
  • Nocturnal acid suppression

Other

  • Alternative when PPI is not preferred / not tolerated

Dosing

STANDARD (ADULT PO)

Adult PO: 20 mg BID or 40 mg daily depending on indication; IV per inpatient protocol — renal-adjust

ADULT DOSE

STANDARD (ADULT): - Typical PO: 20 mg BID or 40 mg daily depending on indication - IV dosing: protocol-based for inpatient use

PEDIATRIC DOSE

Weight-based / protocol-driven only

MAX DOSE

Clinically safe ceiling depends on renal function and indication — emphasize dose/interval reduction in CKD over chasing a fixed max

Practical Note

- Renal adjustment is important (↓ dose / extend interval per guideline or labeling) - Usually less potent than PPI for severe acid suppression needs - Short outpatient trial for dyspepsia/reflux may be reasonable - Persistent symptoms → reassess; do not continue indefinitely without indication review

Warnings

Clinical warnings

  • Duration / reassessment: - Short outpatient trial may be reasonable for dyspepsia / reflux - Persistent symptoms require reassessment (endoscopy / alarm features per pathway) - Do not continue indefinitely without indication review
  • CNS effects in elderly / renal impairment (confusion, agitation)
  • Reduced efficacy versus PPI in severe erosive disease and in many major upper GI bleed / high-acid-suppression protocols
  • Masking serious pathology if symptoms persist without evaluation
  • Thrombocytopenia (rare)
  • Renal dysfunction increases drug exposure

Contraindications

  • Known hypersensitivity

Drug interactions (high-impact)

  • Acid-dependent absorption (e.g., selected azoles, iron, some kinase inhibitors) — clinical relevance varies; check when pH matters
  • Far fewer classic CYP issues than cimetidine; not interchangeable with omeprazole-type interaction expectations

Special populations

Pediatrics

Weight-based / protocol-driven only

Pregnancy

Use according to risk–benefit and local practice; follow current labeling and specialist guidance.

Lactation

See lactation references and product labeling.

Renal impairment

Dose reduction required / extend interval as appropriate; monitor for accumulation and CNS toxicity.

Hepatic impairment

Usually not the primary dose driver versus renal function — follow labeling in combined severe illness.

Elderly

Higher CNS adverse effect risk, especially with renal impairment — start conservative and reassess mental status.

Administration

- PO or IV per indication and protocol - Night dosing useful when nocturnal symptoms dominate - Tie dose/interval to renal function

Monitoring

  • Monitor: - Symptom response - Renal function - Mental status in elderly / renal impairment
  • Recheck: - After trial period or dose change - Earlier if renal function worsens or CNS effects appear - If inadequate symptom control at 48–72h on appropriate dosing → reassess diagnosis / escalate workup; do not continue blindly as chronic self-directed therapy
  • Hold if:
    - Significant confusion / CNS adverse effects
    - Accumulation concerns in worsening renal dysfunction
    - No clear indication after reassessment

Overdose / toxicity

Clinical Picture

Usually mild CNS effects more likely in renal impairment / elderly

Immediate Actions

Stop drug Supportive care

Antidote

No specific antidote

Decontamination

Large acute ingestion: poison center; supportive care mainstay.

Escalation

Severe CNS toxicity or hemodynamic instability → escalate per ED/ICU pathway.

Clinical pearls

Common mistakes, resistance logic, and bedside traps

High-Yield

  • Useful when simpler/shorter-term acid suppression is enough
  • Not a substitute for PPI-level suppression in major GI bleed or severe erosive disease pathways

Clinical

  • If symptoms persist despite famotidine, reassess diagnosis rather than reflexively escalating H2 alone

Safety

  • Most common avoidable error = omitting renal dose adjustment

Pharmacy Tool

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Famotidine 8 mg/mL oral suspension

suspension · oral

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Pharmacokinetics

- Renal clearance important - Exposure rises in kidney dysfunction (dose/interval adjustment)

Mechanism of action

- H2 receptor blockade on parietal cells → reduced gastric acid secretion

Common brand names

Saudi Arabia

Pepcid, Famodar

Global

Fluxid, Famotidine, (placeholder — verify local formulation)

Common trade names are curated examples only — formulations and availability vary. Verify the exact product name with your local pharmacy and national regulator before prescribing or dispensing.

Country practice notes

Global data (no country-specific data available)

  • Follow local antimicrobial stewardship policy, hospital formulary, and national resistance guidance.
  • Confirm dosing, stock, and restrictions with institutional pharmacy and current product labeling.

References

Saudi Arabia

  • SFDA (Saudi Food & Drug Authority)
  • Saudi National Formulary / MOH (where available)

International

  • WHO Model List of Essential Medicines (verify current edition)
  • US FDA or EU EMA product information (when national SmPC is unavailable)
  • ACG dyspepsia / GERD guidance (regional)
  • Inpatient stress ulcer prophylaxis protocols (institutional)
  • FDA / SFDA product labeling (renal dosing)