PEPCID

Clinical safety rating: caution

Comprehensive clinical and safety monograph for PEPCID (PEPCID).

How it works

Competitive antagonist of histamine H2 receptors on gastric parietal cells, reducing basal and stimulated gastric acid secretion by inhibiting cyclic AMP generation.

What the body does with it

Metabolism	Hepatic metabolism via cytochrome P450 enzymes (CYP3A4 and CYP1A2); minor first-pass metabolism; also undergoes sulfoxidation and N-oxidation.
Excretion	Renal: ~65-70% unchanged via tubular secretion (active) and glomerular filtration; hepatic metabolism (S-oxidation) ~30%; fecal: <5%.
Half-life	Terminal elimination half-life: 2.5-3.5 hours in normal renal function; prolonged to 8-10 hours in moderate renal impairment (CrCl 10-50 mL/min) and 15-20 hours in severe impairment (CrCl <10 mL/min); no significant change in hepatic impairment.
Protein binding	~15-20% bound to plasma proteins (primarily albumin).
Volume of Distribution	1.0-1.5 L/kg; large Vd indicates extensive tissue distribution (including cerebrospinal fluid with inflamed meninges).
Bioavailability	Oral: 40-45% (first-pass metabolism reduces bioavailability; food decreases absorption slightly).
Onset of Action	Oral: 30-60 minutes (peak plasma level at 1-3 hours); IV: immediate (within 5 minutes) for acid suppression.
Duration of Action	Oral: 10-12 hours (dose-dependent, 20 mg provides ~10 hours of acid suppression, 40 mg ~12 hours); IV: 8-12 hours.

Classification & Brands

Action Class	Proton pump inhibitors
Brand Substitutes	Kemopraz 20mg Capsule, Omee Capsule, Omecip Capsule, Omesec 20 Capsule

Dosing & administration

20 mg orally twice daily or 40 mg orally once daily at bedtime for duodenal ulcer; 40 mg orally once daily at bedtime for gastric ulcer; 20 mg orally once daily for GERD; 20 mg orally twice daily for erosive esophagitis; 20 mg intravenously every 12 hours for hospitalized patients with pathological hypersecretory conditions.

Dosage form	FOR SUSPENSION
Renal impairment	For creatinine clearance <50 mL/min: reduce oral dose to 50% of normal or extend dosing interval to every 36–48 hours; for intravenous administration, reduce dose to 20 mg every 24 hours.
Liver impairment	No dosage adjustment required for mild to moderate hepatic impairment (Child-Pugh A or B). For severe hepatic impairment (Child-Pugh C), use with caution; specific guidelines not established, consider dose reduction based on clinical response.
Pediatric use	For GERD in children 1–16 years: 1 mg/kg/day divided twice daily (max 40 mg twice daily). For peptic ulcer: 0.5 mg/kg/dose orally at bedtime or divided twice daily (max 40 mg/day). For intravenous use: 0.25 mg/kg every 12 hours (max 20 mg/dose).
Geriatric use	No specific dosage adjustment beyond renal function consideration; initiate at lower end of dosing range due to potential age-related renal impairment, monitor for adverse effects.

Use during pregnancy

1st trimester	Consult provider
2nd trimester	Consult provider
3rd trimester	Consult provider

Clinical note

Comprehensive clinical and safety monograph for PEPCID (PEPCID).

Breastfeeding	Famotidine is excreted in human milk in low amounts; M/P ratio is approximately 1.6. The drug is compatible with breastfeeding due to minimal infant exposure. Caution with premature infants or those with renal impairment.
Teratogenic Risk	Pepcid (famotidine) is FDA Pregnancy Category B. Animal studies have not shown fetal harm, but no adequate controlled studies in pregnant women. First trimester: data limited, risk cannot be excluded. Second and third trimesters: no known teratogenic effects, but use only if clearly needed.

Warnings & precautions

■ FDA Black Box Warning

None

Side Effect Profile

Serious Effects

Absolute Contraindications

Hypersensitivity to famotidine or other H2 receptor antagonists; use with caution in renal impairment (requires dose adjustment); not recommended in pediatric patients without specific indication.

Clinical Precautions

Precautions

Use with caution in elderly patients, those with renal impairment (creatinine clearance <50 mL/min), and severe hepatic impairment; may cause confusion and delirium in elderly; long-term use may lead to vitamin B12 deficiency; abrupt discontinuation may cause rebound gastric acid secretion; potential for false-positive urine protein tests.

Clinical Tips & Counseling

Drug interactions

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PEPCID

Clinical safety rating: caution

Comprehensive clinical and safety monograph for PEPCID (PEPCID).

How it works

Competitive antagonist of histamine H2 receptors on gastric parietal cells, reducing basal and stimulated gastric acid secretion by inhibiting cyclic AMP generation.

What the body does with it

Metabolism	Hepatic metabolism via cytochrome P450 enzymes (CYP3A4 and CYP1A2); minor first-pass metabolism; also undergoes sulfoxidation and N-oxidation.
Excretion	Renal: ~65-70% unchanged via tubular secretion (active) and glomerular filtration; hepatic metabolism (S-oxidation) ~30%; fecal: <5%.
Half-life	Terminal elimination half-life: 2.5-3.5 hours in normal renal function; prolonged to 8-10 hours in moderate renal impairment (CrCl 10-50 mL/min) and 15-20 hours in severe impairment (CrCl <10 mL/min); no significant change in hepatic impairment.
Protein binding	~15-20% bound to plasma proteins (primarily albumin).
Volume of Distribution	1.0-1.5 L/kg; large Vd indicates extensive tissue distribution (including cerebrospinal fluid with inflamed meninges).
Bioavailability	Oral: 40-45% (first-pass metabolism reduces bioavailability; food decreases absorption slightly).
Onset of Action	Oral: 30-60 minutes (peak plasma level at 1-3 hours); IV: immediate (within 5 minutes) for acid suppression.
Duration of Action	Oral: 10-12 hours (dose-dependent, 20 mg provides ~10 hours of acid suppression, 40 mg ~12 hours); IV: 8-12 hours.

Classification & Brands

Action Class	Proton pump inhibitors
Brand Substitutes	Kemopraz 20mg Capsule, Omee Capsule, Omecip Capsule, Omesec 20 Capsule

Dosing & administration

Dosage form	FOR SUSPENSION
Renal impairment	For creatinine clearance <50 mL/min: reduce oral dose to 50% of normal or extend dosing interval to every 36–48 hours; for intravenous administration, reduce dose to 20 mg every 24 hours.
Liver impairment	No dosage adjustment required for mild to moderate hepatic impairment (Child-Pugh A or B). For severe hepatic impairment (Child-Pugh C), use with caution; specific guidelines not established, consider dose reduction based on clinical response.
Pediatric use	For GERD in children 1–16 years: 1 mg/kg/day divided twice daily (max 40 mg twice daily). For peptic ulcer: 0.5 mg/kg/dose orally at bedtime or divided twice daily (max 40 mg/day). For intravenous use: 0.25 mg/kg every 12 hours (max 20 mg/dose).
Geriatric use	No specific dosage adjustment beyond renal function consideration; initiate at lower end of dosing range due to potential age-related renal impairment, monitor for adverse effects.

Use during pregnancy

1st trimester	Consult provider
2nd trimester	Consult provider
3rd trimester	Consult provider

Clinical note

Comprehensive clinical and safety monograph for PEPCID (PEPCID).

Breastfeeding	Famotidine is excreted in human milk in low amounts; M/P ratio is approximately 1.6. The drug is compatible with breastfeeding due to minimal infant exposure. Caution with premature infants or those with renal impairment.
Teratogenic Risk	Pepcid (famotidine) is FDA Pregnancy Category B. Animal studies have not shown fetal harm, but no adequate controlled studies in pregnant women. First trimester: data limited, risk cannot be excluded. Second and third trimesters: no known teratogenic effects, but use only if clearly needed.

Warnings & precautions

■ FDA Black Box Warning

None

Side Effect Profile

Serious Effects

Absolute Contraindications

Hypersensitivity to famotidine or other H2 receptor antagonists; use with caution in renal impairment (requires dose adjustment); not recommended in pediatric patients without specific indication.