PEPCID PRESERVATIVE FREE
Clinical safety rating: caution
Comprehensive clinical and safety monograph for PEPCID PRESERVATIVE FREE (PEPCID PRESERVATIVE FREE).
Competitive antagonist of histamine at H2 receptors on gastric parietal cells, inhibiting gastric acid secretion.
| Metabolism | Hepatic metabolism primarily via sulfoxidation and minor oxidative pathways; limited first-pass effect. |
| Excretion | Renal (65-70% unchanged by tubular secretion); minor biliary/fecal elimination (<30%). Clearance correlates with creatinine clearance. |
| Half-life | 2.5-3.5 hours (normal renal function); prolonged to 20-30 hours in severe renal impairment (CrCl <10 mL/min). Clinical context: dose adjustment required in renal insufficiency. |
| Protein binding | 15-20% bound to plasma proteins. |
| Volume of Distribution | 1.0-1.5 L/kg; indicates extensive extravascular distribution. |
| Bioavailability | Oral: 40-45% (first-pass metabolism); IM: 90-100%. |
| Onset of Action | Oral: 60 minutes; IV: within 30 minutes; IM: 30-60 minutes. Effect on gastric acid secretion begins within 1 hour. |
| Duration of Action | 6-12 hours (dose-dependent); single dose suppresses 80-95% of basal acid secretion for 10-12 hours. Clinical note: used in once-daily dosing for GERD. |
20 mg intravenously over at least 2 minutes or as an infusion over 15-30 minutes every 12 hours; alternatively, 20 mg orally once or twice daily.
| Dosage form | INJECTABLE |
| Renal impairment | CrCl < 50 mL/min: reduce intravenous dose to 20 mg every 24 hours; for oral administration, reduce dose to 20 mg once daily or 50% of usual dose. |
| Liver impairment | No specific dose adjustment required for hepatic impairment; however, caution in severe hepatic dysfunction. |
| Pediatric use | For children 1-16 years: 0.25-0.5 mg/kg/dose intravenously every 12 hours (max 40 mg/day); oral: 0.5 mg/kg/dose twice daily (max 40 mg/day). |
| Geriatric use | No specific dose adjustment, but consider age-related renal impairment; may require dose reduction based on CrCl. |
| 1st trimester | Consult provider |
| 2nd trimester | Consult provider |
| 3rd trimester | Consult provider |
Clinical note
Comprehensive clinical and safety monograph for PEPCID PRESERVATIVE FREE (PEPCID PRESERVATIVE FREE).
| Breastfeeding | Famotidine is excreted in human milk at low concentrations (M/P ratio approximately 0.5). Limited data suggest no adverse effects in breastfed infants. Use caution and monitor infant for potential side effects such as irritability or feeding difficulties. |
| Teratogenic Risk | First trimester: No evidence of increased risk for major malformations based on prospective cohort studies. Second and third trimesters: No reported adverse fetal effects. Animal studies show no teratogenicity at doses up to 500 mg/kg/day. |
■ FDA Black Box Warning
None.
| Serious Effects |
["Hypersensitivity to famotidine or other H2 receptor antagonists."]
| Precautions | ["May cause delirium, confusion, and hallucinations, especially in elderly or renally impaired patients.","Adjust dose in renal impairment (CrCl <50 mL/min).","Potential for cross-sensitivity in patients with hypersensitivity to other H2 antagonists.","May mask symptoms of gastric cancer.","Use in pregnancy only if clearly needed; excreted in breast milk."] |
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| Fetal Monitoring |
| No specific maternal or fetal monitoring required beyond routine prenatal care. Monitor maternal renal function if high doses used long-term. |
| Fertility Effects | No adverse effects on fertility observed in animal studies. Human data insufficient to assess impact on fertility. |