PEPCID RPD
Clinical safety rating: caution
Comprehensive clinical and safety monograph for PEPCID RPD (PEPCID RPD).
Competitive antagonist of histamine H2 receptors in gastric parietal cells, inhibiting gastric acid secretion (basal and stimulated).
| Metabolism | Metabolized in the liver via sulfoxidation and N-demethylation; CYP450 isoenzymes not significantly involved. |
| Excretion | Renal (25-30% as unchanged drug); biliary/fecal (approximately 70% as metabolites); hepatic metabolism to famotidine S-oxide. |
| Half-life | Terminal elimination half-life 2.5-3.5 hours (prolonged to ~12-20 hours in renal impairment; CrCl <10 mL/min). |
| Protein binding | 15-20% (mainly to albumin). |
| Volume of Distribution | 1.0-1.5 L/kg (extensive extravascular distribution). |
| Bioavailability | Oral bioavailability 40-50% (first-pass metabolism); IV is 100%. |
| Onset of Action | Orally disintegrating tablet: 30-60 minutes (peak effect at 1-3 hours); intravenous: immediate within 30 minutes. |
| Duration of Action | Gastric acid suppression up to 10-12 hours (single dose); therapeutic effect persists up to 24 hours for ulcer healing. |
20 mg orally 1-2 times daily for GERD; 40 mg orally once daily for duodenal ulcer or erosive esophagitis. Max 40 mg/day.
| Dosage form | TABLET, ORALLY DISINTEGRATING |
| Renal impairment | CrCl <50 mL/min: reduce dose to 50% or extend interval to every 36-48 hours. |
| Liver impairment | No adjustment required for mild to moderate impairment (Child-Pugh A/B). Severe impairment (Child-Pugh C): reduce dose by 50% or extend interval. |
| Pediatric use | Children ≥12 years: same as adult. 1-11 years: 1 mg/kg/day divided twice daily; max 40 mg/day. Infants <1 year: 0.5 mg/kg once daily. |
| Geriatric use | Initiate at 20 mg once daily; reduce dose if renal impairment present (CrCl <50 mL/min). |
| 1st trimester | Consult provider |
| 2nd trimester | Consult provider |
| 3rd trimester | Consult provider |
Clinical note
Comprehensive clinical and safety monograph for PEPCID RPD (PEPCID RPD).
| Breastfeeding | Famotidine is excreted into human breast milk in low concentrations. The milk-to-plasma ratio is approximately 1.0 (range 0.5-1.5). Infant exposure is estimated at 1-6% of the maternal dose. Considered compatible with breastfeeding due to minimal risk, but caution in premature infants or those with renal impairment. |
| Teratogenic Risk | Famotidine (PEPCID RPD) is classified as FDA Pregnancy Category B. Animal studies have not demonstrated fetal risk, and there are no adequate and well-controlled studies in pregnant women. No known teratogenic effects in first trimester; second and third trimester use is considered safe based on available data. |
■ FDA Black Box Warning
None.
| Serious Effects |
["Hypersensitivity to famotidine or any component of the formulation","Cross-sensitivity with other H2 antagonists (potential risk)"]
| Precautions | ["May cause B12 deficiency with long-term use due to decreased absorption of protein-bound vitamin B12","May increase risk of Clostridioides difficile infection","Hypersensitivity reactions including anaphylaxis","Reversible mental confusion (especially in elderly patients or those with renal impairment)","May mask symptoms of gastric malignancy","Use with caution in patients with renal impairment (dose adjustment required)","May cause false positive results in urine protein tests (with sulfosalicylic acid)"] |
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| Fetal Monitoring | No specific fetal monitoring required. Maternal monitoring includes routine pregnancy care and assessment for adverse effects such as headache, dizziness, constipation, or diarrhea. In neonates, watch for irritability or sedation if maternal high doses used near term. |
| Fertility Effects | No known adverse effects on fertility in animal studies or human data. Famotidine does not alter hormone levels or reproductive function. |