PEPCID AC
Clinical safety rating: caution
Comprehensive clinical and safety monograph for PEPCID AC (PEPCID AC).
Competitive antagonist of histamine H2 receptors on gastric parietal cells, reducing basal and stimulated gastric acid secretion.
| Metabolism | Hepatic metabolism via cytochrome P450 (CYP1A2, CYP2C19, CYP2D6, CYP3A4) to metabolites (famotidine S-oxide) and renal excretion (65-70% unchanged). |
| Excretion | Renal (65-70% as unchanged drug), hepatic metabolism (minor), biliary/fecal (approx. 30%) |
| Half-life | 2.5-3.5 hours (prolonged in renal impairment, e.g., CrCl <30 mL/min: up to 20 hours) |
| Protein binding | 15-20% (primarily to albumin) |
| Volume of Distribution | 1.0-1.5 L/kg (distributes widely into tissues, including breast milk and placenta) |
| Bioavailability | Oral: 40-45% (first-pass metabolism; food may reduce absorption) |
| Onset of Action | Oral: 1 hour; IV: within 30 minutes |
| Duration of Action | Oral: 6-12 hours (dose-dependent); IV: 10-12 hours (up to 24 hours with continuous infusion) |
20 mg orally twice daily for 12 weeks for erosive esophagitis; 20 mg orally once daily for 4-8 weeks for GERD; 10 mg orally once daily for OTC use for heartburn.
| Dosage form | TABLET |
| Renal impairment | CrCl < 50 mL/min: 50% dose reduction or extended dosing interval (e.g., 20 mg every 48 hours). |
| Liver impairment | No dosage adjustment required for mild to moderate hepatic impairment. Severe impairment: use with caution, no specific guidelines. |
| Pediatric use | For GERD: 1-16 years: 1 mg/kg/day divided twice daily, max 40 mg/day. For erosive esophagitis: 2-4 mg/kg/day divided twice daily, max 80 mg/day. |
| Geriatric use | Start at lowest effective dose (e.g., 10 mg orally once daily); monitor renal function and adjust dose if CrCl < 50 mL/min as per renal adjustment. |
| 1st trimester | Consult provider |
| 2nd trimester | Consult provider |
| 3rd trimester | Consult provider |
Clinical note
Comprehensive clinical and safety monograph for PEPCID AC (PEPCID AC).
| Breastfeeding | Famotidine is excreted into human milk in low concentrations. M/P ratio is approximately 1.78. The American Academy of Pediatrics considers it compatible with breastfeeding. Caution is advised in nursing mothers due to potential for adverse effects in the infant. |
| Teratogenic Risk | No increased risk of major congenital malformations observed in human studies across all trimesters. Animal studies show no evidence of impaired fertility or harm to the fetus at doses up to 200 times the human dose. |
| Fetal Monitoring |
■ FDA Black Box Warning
None.
| Serious Effects |
Hypersensitivity to famotidine or other H2 antagonists.
| Precautions | May mask symptoms of gastric malignancy; adjust dose in renal impairment (CrCl <50 mL/min); rare CNS effects (confusion, hallucinations) especially in elderly or severe renal disease; QT prolongation risk in susceptible patients. |
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| No specific fetal monitoring required. Routine prenatal care is sufficient. |
| Fertility Effects | No adverse effects on fertility reported in animal studies at doses up to 200 times the human dose. Human data on fertility are limited but no significant effects have been documented. |