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Pronunciation
(fa MOE ti deen)
U.S. Brand Names
Generic Available
Yes: Injection, tablet
Canadian Brand Names
Pharmacologic Category
Pharmacologic Category Synonyms
Use: Labeled Indications
Maintenance therapy and treatment of duodenal ulcer; treatment of gastroesophageal reflux, active benign gastric ulcer, and pathological hypersecretory conditions
OTC labeling: Relief of heartburn, acid indigestion, and sour stomach
Use: Unlabeled/Investigational
Part of a multidrug regimen for H. pylori eradication to reduce the risk of duodenal ulcer recurrence; stress ulcer prophylaxis in critically-ill patients; symptomatic relief in gastritis
Pregnancy Risk Factor
B
Pregnancy Considerations
Crosses the placenta. There are no adequate and well-controlled studies in pregnant women. Use only if clearly needed.
Lactation
Enters breast milk/not recommended
Breast-Feeding Considerations
Famotidine is concentrated in breast milk, but to a lesser degree than cimetidine or ranitidine; some sources prefer its use if one of these agents is needed.
Contraindications
Hypersensitivity to famotidine, other H2 antagonists, or any component of the formulation
Warnings/Precautions
Concerns related to adverse effects.
• Confusion: Reversible confusional states, usually clearing within 3-4 days after discontinuation, have been linked to use. Increased age (>50 years) and renal or hepatic impairment are thought to be associated.
Disease-related concerns:
• Gastric malignancy: Relief of symptoms does not preclude the presence of a gastric malignancy.
• Renal impairment: Use with caution in patients with moderate-to-severe renal impairment (Clcr <50 mL/minute); dosage adjustment recommended.
Dosage form specific issues:
• Benzyl alcohol: Multidose vials for injection contain benzyl alcohol which has been associated with "gasping syndrome" in neonates.
Other warnings/precautions:
• OTC labeling: When used for self-medication, patients should be instructed not to use if they have difficulty swallowing, are vomiting blood, or have bloody or black stools. Not for use with other acid reducers.
Adverse Reactions
Note: Agitation and vomiting have been reported in up to 14% of pediatric patients <1 year of age.
1% to 10%:
Central nervous system: Headache (5%), dizziness (1%)
Gastrointestinal: Diarrhea (2%), constipation (1%)
<1% (Limited to important or life-threatening): Abdominal discomfort, acne, agitation, agranulocytosis, allergic reaction, alopecia, anaphylaxis, angioedema, anorexia, anxiety, arrhythmia, arthralgia, AV block, bradycardia, bronchospasm, BUN/creatinine increased, cholestatic jaundice, confusion, decreased libido, depression, drowsiness, facial edema, fatigue, fever, flushing, hallucinations, injection site reactions, insomnia, interstitial pneumonia, jaundice, nausea, leukopenia, liver function tests increased, muscle cramps, palpitation, pancytopenia, paresthesia, proteinuria, pruritus, rash, seizure, somnolence, Stevens-Johnson syndrome, tinnitus, thrombocytopenia, toxic epidermal necrolysis, urticaria, vomiting, weakness, xerostomia
Drug Interactions
Antifungal Agents (Azole Derivatives, Systemic): H2-Antagonists may decrease the absorption of Antifungal Agents (Azole Derivatives, Systemic). Exceptions: Miconazole; Voriconazole. Risk D: Consider therapy modification
Atazanavir: H2-Antagonists may decrease the absorption of Atazanavir. Risk D: Consider therapy modification
Cefpodoxime: H2-Antagonists may decrease the absorption of Cefpodoxime. Separate oral doses by at least 2 hours. Risk C: Monitor therapy
Cefuroxime: H2-Antagonists may decrease the absorption of Cefuroxime. Separate oral doses by at least 2 hours. Risk C: Monitor therapy
Dasatinib: H2-Antagonists may decrease the absorption of Dasatinib. Risk D: Consider therapy modification
Fosamprenavir: H2-Antagonists may decrease the serum concentration of Fosamprenavir. Cimetidine may also inhibit the metabolism of the active metabolite amprenavir, making its effects on fosamprenavir/amprenavir concentrations difficult to predict. Risk C: Monitor therapy
Iron Salts: H2-Antagonists may decrease the absorption of Iron Salts. Exceptions: Ferric Gluconate; Iron Dextran Complex; Iron Sucrose. Risk C: Monitor therapy
Saquinavir: H2-Antagonists may increase the serum concentration of Saquinavir. Risk C: Monitor therapy
Ethanol/Nutrition/Herb Interactions
Ethanol: Avoid ethanol (may cause gastric mucosal irritation).
Food: Famotidine bioavailability may be increased if taken with food.
Storage
Oral:
Powder for oral suspension: Prior to mixing, dry powder should be stored at controlled room temperature of 25°C (77°F). Reconstituted oral suspension is stable for 30 days at room temperature; do not freeze.
Tablet: Store controlled room temperature. Protect from moisture.
I.V.:
Solution for injection: Prior to use, store at 2°C to 8°C (36°F to 46°F). If solution freezes, allow to solubilize at controlled room temperature.
I.V. push: Following preparation, solutions for I.V. push should be used immediately, or may be stored in refrigerator and used within 48 hours.
Infusion: Following preparation, the manufacturer states may be stored for up to 48 hours under refrigeration; however, solutions for infusion have been found to be physically and chemically stable for 7 days at room temperature.
Solution for injection, premixed bags: Store at controlled room temperature of 25°C (77°F). Avoid excessive heat.
Reconstitution
Solution for injection:
I.V. push: Dilute famotidine with NS (or another compatible solution) to a total of 5-10 mL (some centers also administer undiluted).
Infusion: Dilute with D5W 100 mL or another compatible solution.
Compatibility
Stable in D5W, D10W, LR, fat emulsion 10%, NS, sodium bicarbonate 5%; variable stability (consult detailed reference) in TPN.
Y-site administration: Compatible: Acyclovir, allopurinol, amifostine, aminophylline, ampicillin, ampicillin/sulbactam, amsacrine, atropine, aztreonam, calcium gluconate, cefazolin, cefoperazone, cefotaxime, cefotetan, cefoxitin, ceftazidime, ceftizoxime, ceftriaxone, cefuroxime, chlorpromazine, cisatracurium, cisplatin, cladribine, cyclophosphamide, cytarabine, dexamethasone sodium phosphate, dextran 40, digoxin, diphenhydramine, dobutamine, docetaxel, dopamine, doxorubicin, doxorubicin liposome, droperidol, enalaprilat, epinephrine, erythromycin lactobionate, esmolol, etoposide, filgrastim, fluconazole, fludarabine, folic acid, gatifloxacin, gemcitabine, gentamicin, granisetron, haloperidol, heparin, hydrocortisone, hydrocortisone sodium succinate, hydromorphone, hydroxyzine, imipenem/cilastatin, inamrinone, insulin (regular), isoproterenol, labetalol, lidocaine, linezolid, lorazepam, magnesium sulfate, melphalan, meperidine, methotrexate, methylprednisolone sodium succinate, metoclopramide, midazolam, morphine, nafcillin, nitroglycerin, norepinephrine, ondansetron, oxacillin, paclitaxel, perphenazine, phenylephrine, phenytoin, phytonadione, piperacillin, potassium chloride, potassium phosphates, procainamide, propofol, remifentanil, sargramostim, sodium bicarbonate, sodium nitroprusside, teniposide, theophylline, thiamine, thiotepa, ticarcillin, ticarcillin/clavulanate potassium, tirofiban, verapamil, vinorelbine. Incompatible: Amphotericin B cholesteryl sulfate complex, cefepime, piperacillin/tazobactam. Variable (consult detailed reference): Furosemide, TPN.
Compatibility when admixed: Compatible: Cefazolin, flumazenil, vancomycin.
Mechanism of Action
Competitive inhibition of histamine at H2 receptors of the gastric parietal cells, which inhibits gastric acid secretion
Pharmacodynamics/Kinetics
Onset of action: GI: Oral: Within 1-3 hour; I.V.: 30 minutes
Duration: 10-12 hours
Protein binding: 15% to 20%
Bioavailability: Oral: 40% to 45%
Half-life elimination: Injection, oral suspension, tablet: 2.5-3.5 hours; prolonged with renal impairment; Oliguria: >20 hours
Time to peak, serum: Oral: ?1-3 hours
Excretion: Urine (25% to 30% [oral], 65% to 70% [I.V.] as unchanged drug)
Dosage
Children: Treatment duration and dose should be individualized
Peptic ulcer: 1-16 years:
Oral: 0.5 mg/kg/day at bedtime or divided twice daily (maximum dose: 40 mg/day); doses of up to 1 mg/kg/day have been used in clinical studies
I.V.: 0.25 mg/kg every 12 hours (maximum dose: 40 mg/day); doses of up to 0.5 mg/kg have been used in clinical studies
GERD: Oral:
<3 months: 0.5 mg/kg once daily
3-12 months: 0.5 mg/kg twice daily
1-16 years: 1 mg/kg/day divided twice daily (maximum dose: 40 mg twice daily); doses of up to 2 mg/kg/day have been used in clinical studies
Children ?12 years and Adults: Heartburn, indigestion, sour stomach: OTC labeling: Oral: 10-20 mg every 12 hours; dose may be taken 15-60 minutes before eating foods known to cause heartburn
Adults:
Duodenal ulcer: Oral: Acute therapy: 40 mg/day at bedtime for 4-8 weeks; maintenance therapy: 20 mg/day at bedtime
Helicobacter pylori eradication (unlabeled use): 40 mg once daily; requires combination therapy with antibiotics
Gastric ulcer: Oral: Acute therapy: 40 mg/day at bedtime
Hypersecretory conditions: Oral: Initial: 20 mg every 6 hours, may increase in increments up to 160 mg every 6 hours
GERD: Oral: 20 mg twice daily for 6 weeks
Esophagitis and accompanying symptoms due to GERD: Oral: 20 mg or 40 mg twice daily for up to 12 weeks
Patients unable to take oral medication: I.V.: 20 mg every 12 hours
Dosing adjustment in renal impairment: Clcr <50 mL/minute: Manufacturer recommendation: Administer 50% of dose or increase the dosing interval to every 36-48 hours (to limit potential CNS adverse effects).
Administration: Oral
Suspension: Shake vigorously before use. May be taken with or without food.
Tablet: May be taken with or without food.
Administration: I.V.
I.V. push: Inject over at least 2 minutes.
Solution for infusion: Administer over 15-30 minutes.
Administration: I.V. Detail
pH: 5.7-6.4 (premixed solution); 5.0-5.6 (injection)
Patient Education
Do not take any new prescription or OTC medications or herbal products during therapy without consulting prescriber. Take exactly as directed; do not alter dose or frequency. OTC: Follow package instructions; do not use for more than 14 days unless recommended by prescriber. May cause drowsiness or dizziness (use caution when driving or engaging in tasks that require alertness until response to drug is known); constipation (increased exercise, fluids, fruit, or fiber may help); or diarrhea (buttermilk, boiled milk, or yogurt may help). Report acute headache, unresolved constipation or diarrhea, palpitations, black tarry stools, abdominal pain, rash, worsening of condition being treated, or recurrence of symptoms after therapy is completed. Breast-feeding precaution: Consult prescriber if breast-feeding.
Geriatric Considerations
H2 blockers are the preferred drugs for treating PUD in the elderly due to cost and ease of administration. They are no less or more effective than any other therapy. Famotidine is one of the preferred agents (due to side effects, drug interaction profile, and pharmacokinetics). Treatment for PUD in the elderly is recommended for 12 weeks since their lesions are typically larger; therefore, take longer to heal. Always adjust dose based upon creatinine clearance, since slight accumulation may result in CNS side effects, mainly confusion.
Anesthesia and Critical Care Concerns/Other Considerations
The 2008 Surviving Sepsis Campaign guidelines recommend that stress ulcer prophylaxis using an H2 blocker (Grade 1A) or proton pump inhibitor (Grade 1B) be given to patients with severe sepsis to prevent upper GI bleed. Benefit of prevention of upper GI bleed must be weighed against potential effect of increased stomach pH on development of ventilator-associated pneumonia.
Dental Health: Effects on Dental Treatment
No significant effects or complications reported
Dental Health: Vasoconstrictor/Local Anesthetic Precautions
No information available to require special precautions
Mental Health: Effects on Mental Status
May cause dizziness or drowsiness; may rarely cause insomnia
Mental Health: Effects on Psychiatric Treatment
May cause agranulocytosis; use caution with clozapine and carbamazepine
Nursing: Physical Assessment/Monitoring
Assess potential for interactions with other medications patient may be taking (eg, anything that may affect neuromuscular transmission). Evaluate patient response on a regular basis throughout therapy. I.V.: See Administration specifics. Teach patient proper use (eg, timing of administration when used concurrently with other medications), possible side effects/appropriate interventions, and adverse symptoms to report.
Dosage Forms
Excipient information presented when available (limited, particularly for generics); consult specific product labeling.
Gelcap:
Pepcid® AC: 10 mg
Infusion [premixed in NS]: 20 mg (50 mL)
Pepcid®: 20 mg (50 mL)
Injection, solution: 10 mg/mL (4 mL, 20 mL, 50 mL)
Pepcid®: 10 mg/mL (20 mL) [contains benzyl alcohol]
Injection, solution [preservative free]: 10 mg/mL (2 mL)
Pepcid®: 10 mg/mL (2 mL)
Powder for oral suspension:
Pepcid®: 40 mg/5 mL (50 mL) [contains sodium benzoate; cherry-banana-mint flavor]
Tablet: 10 mg [OTC], 20 mg, 40 mg
Pepcid®: 20 mg, 40 mg
Pepcid® AC: 10 mg, 20 mg
Pepcid® AC Maximum Strength: 20 mg
Pricing: U.S. (www.drugstore.com)
Suspension (reconstituted) (Pepcid)
40 mg/5 mL (50): $123.88
Tablets (Famotidine)
20 mg (30): $19.99
40 mg (90): $18.00
Tablets (Pepcid)
20 mg (30): $59.99
40 mg (30): $105.99
Tablets (Pepcid AC)
10 mg (6): $8.99
10 mg (12): $7.99
10 mg (18): $7.99
10 mg (30): $9.35
References
Ahmad S, “Famotidine and Cardiac Arrhythmia,” DICP, 1991, 25(3):315.
Broussard CN and Richter JE, “Treating Gastro-oesophageal Reflux Disease During Pregnancy and Lactation: What Are the Safest Therapy Options,” Drug Saf, 1998, 19(4):325-37.
Dellinger RP, Levy MM, Carlet JM, et al, “Surviving Sepsis Campaign: International Guidelines for Management of Severe Sepsis and Septic Shock: 2008,” Intensive Care Med, 2008, 34(1): 17-60. Available at http://www.survivingsepsis.org/system/files/images/2008_20International_20SSC_20Guidelines_1_.pdf
Fennerty MD and Higbee M, “Drug Therapy of Gastrointestinal Disease,” Geriatric Pharmacology, Bressler R and Katz MD, eds, New York, NY: McGraw-Hill, 1993, 585-608.
Fish DN, “Safety and Cost of Rapid I.V. Injection of Famotidine in Critically Ill Patients,” Am J Health Syst Pharm, 1995, 52(17):1889-94.
Gottlieb S, Decktor DL, Eckert JM, et al, “Efficacy and Tolerability of Famotidine in Preventing Heartburn and Related Symptoms of Upper Gastrointestinal Discomfort,” Am J Ther, 1995, 2:314-9.
Inotsume N, Mishimura M, Nakano M, et al, “Removal of Famotidine by Haemodialysis in Elderly Anuric Patients,” Eur J Clin Pharmacol, 1990, 38(3):313-4.
James LP and Kearns GL, “Pharmacokinetics and Pharmacodynamics of Famotidine in Paediatric Patients,” Clin Pharmacokinet, 1996, 31(2):103-10.
Lipsy RJ and Freeman CD, “Hemodynamic Effects of Intravenous Famotidine in Critically Ill Patients,” Pharmacotherapy,1995, 15(1):48-51.
Simon TJ, Berlin RG, Gardner AH, et al, “Self-Directed Treatment of Intermittent Heartburn: A Randomized, Multicenter, Double-Blind, Placebo-Controlled Evaluation of Antacid and Low Doses of an H2-Receptor Antagonist (Famotidine),” Am J Ther, 1995, 2:304-13.
Treem WR, Davis PM, and Hyams JS, “Suppression of Gastric Acid Secretion by Intravenous Administration of Famotidine in Children,” J Pediatr, 1991, 118(5):812-6.
International Brand Names
Lexi-Comp.com
Last full review/revision August 2008
Content last modified August 2008
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