Pepcid, Pepcid AC
Classifications: antisecretory agent (h2-receptor antagonist);
Therapeutic: antiulcer; h2-receptor antagonist

Prototype: Cimetidine
Pregnancy Category: B


10 mg, 20 mg, 40 mg tablets; 40 mg/5 mL suspension; 10 mg/mL, 20 mg/50 mL injection


A potent competitive inhibitor of histamine at histamine (H2) receptor sites in gastric parietal cells. Inhibits basal, nocturnal, meal-stimulated, and pentagastrin-stimulated gastric secretion; also inhibits pepsin secretion.

Therapeutic Effect

Reduces parietal cell output of hydrochloric acid; thus, detrimental effects of acid on gastric mucosa are diminished.


Short-term treatment of active duodenal ulcer. Maintenance therapy for duodenal ulcer patients on reduced dosage after healing of an active ulcer. Treatment of pathologic hypersecretory conditions (e.g., Zollinger-Ellison syndrome), benign gastric ulcer, gastroesophageal reflux disease (GERD), gastritis.

Unlabeled Uses

Stress ulcer prophylaxis.


Hypersensitivity to famotidine or other H2-receptor antagonists; sudden GI bleeding; lactation.

Cautious Use

Renal insufficiency; renal failure; PKU; hepatic disease; elderly; pregnancy (category B).

Route & Dosage

Duodenal Ulcer
Adult: PO 40 mg h.s. or 20 mg b.i.d. PO Maintenance Therapy 20 mg h.s. IV 20 mg q12h
Child: PO/IV 0.25–0.5 mg/kg q12h (max: 40 mg/d)

Pathological Hypersecretory Conditions
Adult: PO 20–160 mg q6h IV 20 mg q6h

GERD, Gastritis
Adult: PO 10 mg b.i.d.
Child: PO 1 mg/kg/d in 2 divided doses (max: 40 mg b.i.d.)

Renal Impairment
Clcr <50 mL/min: 50% of usual dose or usual dose q36–48h


  • Give with liquid or food of patient's choice; an antacid may also be given if patient is also on antacid therapy.
  • Store at 15°–30° C (59°–86° F). Protect from moisture and strong light; do not freeze.
  • Note: Verify correct IV concentration and rate of infusion/injection with physician before administration to infants or children.

PREPARE: Direct: Dilute 20 mg (2 mL) famotidine IV solution (containing 10 mg/mL) with D5W, NS, or other compatible IV diluent (see manufacturer's directions) to a total volume of 5 or 10 mL.  IV Infusion: Dilute 2 mL famotidine IV with 100 mL compatible IV solution.  

ADMINISTER: Direct: Give over not less than 2 min.  IV Infusion: Infuse over 15–30 min.  

INCOMPATIBILITIES Y-site: Amphotericin B cholesteryl complex, azithromycin, cefepime, piperacillin/tazobactam.

  • Store IV solution at 2°–8° C (36°–46° F); reconstituted IV solution is stable for 48 h at room temperature 15°–30° C (59°–86° F).

Adverse Effects (≥1%)

CNS: Dizziness, headache, confusion, depression. GI: Constipation, diarrhea. Skin: Rash, acne, pruritus, dry skin, flushing. Hematologic: Thrombocytopenia. Urogenital: Increases in BUN and serum creatinine.


Drug: May inhibit absorption of itraconazole or ketoconazole.


Absorption: Incompletely from GI tract (40–50% reaches systemic circulation). Onset: 1 h. Peak: 1–3 h PO; 0.5–3 h IV. Duration: 10–12 h. Metabolism: In liver. Elimination: In urine. Half-Life: 2.5–4 h.

Nursing Implications

Assessment & Drug Effects

  • Monitor for improvement in GI distress.
  • Monitor for signs of GI bleeding.

Patient & Family Education

  • Be aware that pain relief may not be experienced for several days after starting therapy.

Common adverse effects in italic, life-threatening effects underlined; generic names in bold; classifications in SMALL CAPS; Canadian drug name; Prototype drug

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