famotidine (Rx, OTC)

Brand and Other Names:Pepcid, Act, more...Dyspep HB, Fluxid, Acid Controller
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Dosing & Uses

AdultPediatric

Dosage Forms & Strengths

injection solution

  • 10mg/mL
  • 0.4mg/mL

oral suspension

  • 40mg/5mL

tablet

  • 10mg
  • 20mg
  • 40mg

tablet, chewable

  • 10mg
  • 20mg
more...

Duodenal Ulcer

Acute treatment: 20 mg PO/IV q12hr or 40 mg PO at bedtime for 4-8 weeks

Maintenance: 20 mg PO at bedtime

Benign Gastric Ulcer

40 mg PO at bedtime

Gastroesophageal Reflux Disease

20 mg PO q12hr for 6 weeks

With esophagitis: 20-40 mg PO q12hr for up to 12 weeks

Hypersecretory Conditions

20 mg PO/IV q6hr; may increase up to 160 mg q6hr

Heartburn

10-20 mg q12 hr; may take 15-60 min before eating foods that could cause heartburn

Dosing Modifications

CrCl <50 mL/min: Give 50% of usual dose, or prolong dosing interval to q36-48hr

Dosage Forms & Strengths

injection solution

  • 10mg/mL
  • 0.4mg/mL

oral suspension

  • 40mg/5mL

tablet

  • 10mg
  • 20mg
  • 40mg

tablet, chewable

  • 10mg
  • 20mg
more...

Peptic Ulcer

1-16 years: 0.25 mg/kg IV q12hr or 0.5 mg/kg PO at bedtime; not to exceed 40 mg/day  

Gastroesophageal Reflux Disease

<3 months: 0.5 mg/kg PO once daily for up to 8 weeks  

3-12 months: 0.5 mg/kg PO q12hr for up to 8 weeks

1-16 years: 1 mg/kg/day PO divided q12hr; individual dose not to exceed 40 mg

Heartburn

<12 years: Not established

>12 years: 10-20 mg q12 hr; may take 15-60 min before eating foods that could cause heartburn

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Interactions

Interaction Checker

and famotidine

No Results

     activity indicator 
    No Interactions Found
    Interactions Found

    Contraindicated

      Serious - Use Alternative

        Significant - Monitor Closely

          Minor

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            Adverse Effects

            1-10%

            Headache (4.7%)

            Diarrhea (1.7%)

            Dizziness (1.3%)

            Constipation (1.2%)

            Frequency Not Defined

            Body as a whole: Fever, asthenia, fatigue

            Cardiovascular: Arrhythmia, AV block, palpitation; prolonged QT interval in patients with impaired renal function, has been reported very rarely

            Gastrointestinal: Cholestatic jaundice, hepatitis, liver enzyme abnormalities, vomiting, nausea, abdominal discomfort, anorexia, dry mouth

            Hematologic: Rare cases of agranulocytosis, pancytopenia, leukopenia, thrombocytopenia

            Hypersensitivity: Anaphylaxis, angioedema, orbital or facial edema, urticaria, rash, conjunctival injection

            Musculoskeletal: Rhabdomyolysis, musculoskeletal pain including muscle cramps, arthralgia

            Nervous system/psychiatric: Grand mal seizure; psychic disturbances, which were reversible in cases for which follow-up was obtained, including hallucinations, confusion, agitation, depression, anxiety, decreased libido; paresthesia; insomnia; somnolence; convulsions, in patients with impaired renal function, have been reported very rarely

            Respiratory: Bronchospasm, interstitial pneumonia

            Skin: Toxic epidermal necrolysis/Stevens-Johnson syndrome (very rare), alopecia, acne, pruritus, dry skin, flushing

            Special senses: Tinnitus, taste disorder

            Rare cases of impotence and rare cases of gynecomastia

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            Warnings

            Contraindications

            Hypersensitivity to famotidine or other H2-receptor antagonists

            Cautions

            Use caution in renal impairment; dosage adjustment recommended in moderate to severe renal impairment (CrCl <50 mL/min)

            Prolonged QT interval reported rarely in patients with renal impairment whose dose or dosing interval may not have been adjusted appropriately

            Central nervous system (CNS) adverse effects, including confusion, delirium, hallucinations, disorientation, agitation, seizures, and lethargy, reported with moderate-to-severe renal impairment; since famotidine blood levels are higher in patients with renal impairment than in patients with normal renal function, dosage adjustments are recommended in patients with renal impairment

            Relief of symptoms does not eliminate the presence of gastric malignancy

            State of confusion reported with use; risk increased in >50 years of age and/or renal/hepatic impairment

            Prolonged treatment (>2 years) may lead to vitamin B12 malabsorption, which can result in vitamin B12 deficiency; magnitude of deficiency is dose related; occurs most frequently in females and those younger then 30 years

            Patients should not use OTC if difficulty swallowing, vomiting blood, have bloody or black stools

            If patient taking a prescription drug, the patient should ask a doctor or a pharmacist whether acid reducers can be taken concomitantly with it

            Patients with kidney disease should ask doctor before use

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            Pregnancy & Lactation

            Pregnancy

            Available data in pregnant women are insufficient to establish a drug-associated risk of major birth defects, miscarriage or adverse maternal or fetal outcomes

            Animal data

            • Animal reproduction studies have shown no adverse development effects at doses up to approximately 243 times, the recommended human dose of 80 mg per day for treatment of erosive esophagitis

            Lactation

            There are limited data available on presence in human breast milk; there were no effects on breastfed infant; there are no data on famotidine effects on milk production; drug reported present in milk of lactating rats; developmental and health benefits of breastfeeding should be considered along with mother’s clinical need for famotidine and any potential adverse effects on breastfed child or from underlying maternal condition

            Pregnancy Categories

            A:Generally acceptable. Controlled studies in pregnant women show no evidence of fetal risk.

            B:May be acceptable. Either animal studies show no risk but human studies not available or animal studies showed minor risks and human studies done and showed no risk.

            C:Use with caution if benefits outweigh risks. Animal studies show risk and human studies not available or neither animal nor human studies done.

            D:Use in LIFE-THREATENING emergencies when no safer drug available. Positive evidence of human fetal risk.

            X:Do not use in pregnancy. Risks involved outweigh potential benefits. Safer alternatives exist.

            NA:Information not available.

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            Pharmacology

            Mechanism of Action

            Blocks H2 receptors of gastric parietal cells, leading to inhibition of gastric secretions

            Absorption

            Bioavailability: 40-45% (PO; minimal 1st-pass metabolism)

            Onset: <1 hr (PO); <30 min (IV)

            Duration: 10-12 hr

            Peak plasma time: IV, 20 min; PO, 1-4 hr

            Distribution

            Protein bound: 15-20%

            Vd: 1.1-1.4 L/kg (Adults); 1.5-2.07 L/kg (children); 1.4-1.8 L/kg (infants <3 months); 2.3 L/kg (infants 3-12 months)

            Metabolism

            Metabolized in liver

            Metabolites: Famotidine S-oxide (inactive)

            Elimination

            Half-life: 2.5-4 hr (adults; increases with renal impairment; eg, 20 hr with CrCl <10 mL/min); 3-4 hr (children); 4.5 hr (infants 3-12 months); 8-10.5 hr (infants < 3 months)

            Dialyzable: No

            Renal clearance: 250-450 mL/min

            Total body clearance: 381-483 mL/min

            Excretion: Urine (25-30% as unchanged drug when administered PO; 70% when adminsitered IV)

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            Administration

            IV Incompatibilities

            Additive: Piperacillin-tazobactam

            Y-site: Cefepime, piperacillin-tazobactam, amphotericin B, azithromycin, furosemide (at 2 mg/mL famotidine; compatible at 0.2 mg/mL)

            IV Compatibilities

            Additive: Aztreonam, ceftazidime, dobutamine, dopamine, furosemide, gentamicin, imipenem, thiamine

            Y-site: Atropine, cefazolin, furosemide, gentamicin, heparin, norepinephrine, thiamine

            IV Preparation

            Dilute 20 mg to total of 5 or 10 mL with NS, D5W, or LR

            Also available in premixed bag containing 20 mg in 50 mL NS

            IV Administration

            Infuse at rate no faster than 10 mg/min

            Storage

            Premixed: Store at room temperature

            Unmixed: Store in refrigerator at 2-8°C (36-46°F)

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            Images

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            Formulary

            FormularyPatient Discounts

            Adding plans allows you to compare formulary status to other drugs in the same class.

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            The above information is provided for general informational and educational purposes only. Individual plans may vary and formulary information changes. Contact the applicable plan provider for the most current information.

            Tier Description
            1 This drug is available at the lowest co-pay. Most commonly, these are generic drugs.
            2 This drug is available at a middle level co-pay. Most commonly, these are "preferred" (on formulary) brand drugs.
            3 This drug is available at a higher level co-pay. Most commonly, these are "non-preferred" brand drugs.
            4 This drug is available at a higher level co-pay. Most commonly, these are "non-preferred" brand drugs or specialty prescription products.
            5 This drug is available at a higher level co-pay. Most commonly, these are "non-preferred" brand drugs or specialty prescription products.
            6 This drug is available at a higher level co-pay. Most commonly, these are "non-preferred" brand drugs or specialty prescription products.
            NC NOT COVERED – Drugs that are not covered by the plan.
            Code Definition
            PA Prior Authorization
            Drugs that require prior authorization. This restriction requires that specific clinical criteria be met prior to the approval of the prescription.
            QL Quantity Limits
            Drugs that have quantity limits associated with each prescription. This restriction typically limits the quantity of the drug that will be covered.
            ST Step Therapy
            Drugs that have step therapy associated with each prescription. This restriction typically requires that certain criteria be met prior to approval for the prescription.
            OR Other Restrictions
            Drugs that have restrictions other than prior authorization, quantity limits, and step therapy associated with each prescription.
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            Medscape prescription drug monographs are based on FDA-approved labeling information, unless otherwise noted, combined with additional data derived from primary medical literature.