FAMOTIDINE

The active ingredient in famotidine tablets, USP is a histamine-2 (H2) receptor antagonist. Famotidine is N’-(aminosulfonyl)-3-[[[2[(diaminomethylene)amino]-4-thiazolyl]methyl]thio]propanimidamide. The empirical formula of famotidine is C8H15N7O2S3 and its molecular weight is 337.43. Its structural formula is: [Structure] Each famotidine tablet, USP for oral administration contains either 20 mg or 40 mg of famotidine and the following inactive ingredients: colloidal silicon dioxide, yellow iron oxide and red iron oxide, Lecithin, macrogel/PEG 3350, magnesium stearate, microcrystalline cellulose, polyvinyl alcohol, pregelatinized starch, talc and titanium dioxide. Famotidine, USP is a white to pale yellow crystalline compound that is freely soluble in glacial acetic acid, slightly soluble in methanol, very slightly soluble in water, and practically insoluble in ethanol.

Famotidine tablets are indicated in adult and pediatric patients 40 kg and greater for the treatment of: active duodenal ulcer (DU). active gastric ulcer (GU). symptomatic nonerosive gastroesophageal reflux disease (GERD). erosive esophagitis due to GERD, diagnosed by biopsy. Famotidine tablets are indicated in adults for the: treatment of pathological hypersecretory conditions (e.g., Zollinger-Ellison syndrome, multiple endocrine neoplasias). reduction of the risk of duodenal ulcer recurrence.

1 Recommended Dosage Table 1 shows the recommended dosage of famotidine 20 mg and 40 mg tablets in adult and pediatric patients weighing 40 kg and greater with normal renal function. The use of famotidine 20 mg and 40 mg tablets is not recommended in pediatric patients weighing less than 40 kg because the lowest available strength (20 mg) exceeds the recommended dose for these patients. Use another famotidine formulation for pediatric patients weighing less than 40 kg. Table 1: Recommended Dosage and Duration of Famotidine Tablets in Adult and Pediatric Patients 40 kg and Greater with Normal Renal Function Indication Recommended Dosage Recommended Duration Active duodenal ulcer (DU) 40 mg once daily; or 20 mg twice dailya Up to 8 weeksb,c Active gastric ulcer 40 mg once daily Up to 8 weeksc Symptomatic nonerosive GERD 20 mg twice daily Up to 6 weeksc Erosive esophagitis diagnosed by endoscopy 20 mg twice daily; or 40 mg twice dailya Up to 12 weeks Pathological hypersecretory conditionsd Starting dosage: 20 mg every 6 hours; adjust dosage to individual patient needs Maximum dosage 160 mg every 6 hours As clinically indicated Reduction of the risk of DU recurrenced 20 mg once daily 1 yearc or as clinically indicated a Both dosages demonstrated effectiveness in clinical trials [see Clinical Studies (14)]. b In clinical trials, the majority of patients healed within 4 weeks. For patients who do not heal after 4 weeks, consider an additional 2 to 4 weeks of treatment [see Clinical Studies (14.1)]. c Longer treatment durations have not been studied in clinical trials [see Clinical Studies (14.1, 14.2, 14.3)]. d In pediatric patients, the safety and effectiveness of famotidine tablets have not been established for the reduction of the risk of duodenal ulcer recurrence or for treatment of pathological hypersecretory conditions [see Use in Specific Populations (8.4)]. 2.2 Dosage in Renal Impairment Dosage adjustments of famotidine tablets are recommended for patients with moderate to severe renal impairment (creatinine clearance less than 60 mL/min) [see Use in Specific Populations (8.6)]. Table 2 shows the recommended maximum dosage of famotidine tablets 20 mg or 40 mg tablets for patients with renal impairment, by indication. Use the lowest effective dose. Some dosage adjustments may require switching to other formulations of famotidine (e.g., oral suspension, lower dose tablet). Table 2: Recommended Maximum Dosage of Famotidine Tablets in Adult and Pediatric Patients 40 kg and Greater with Moderate and Severe Renal Impairment Indication Recommended Maximum Dosages Creatinine clearance 30 to 60 mL/minute Creatinine clearance less than 30 mL/minute Active duodenal ulcer (DU) 20 mg once daily; or 40 mg every other day 20 mg every other daya Active gastric ulcer 20 mg once daily; or 40 mg every other day 20 mg every other daya Symptomatic nonerosive GERD 20 mg once daily 20 mg every other daya Erosive esophagitis diagnosed by endoscopyb 20 mg once daily; or 40 mg every other dayb 20 mg every other daya,b 40 mg once dailyb 20 mg once dailyb Pathological hypersecretory conditionsc Avoid used Reduction of the risk of DU recurrencec 20 mg every other daya (see footnote)e a An alternate dosage regimen is 10 mg once daily. Since 20 mg or 40 mg tablet strength cannot be used for this dosage regimen, use an alternate famotidine formulation. b Dosage adjustments for renal impairment are provided for both dosing regimens (20 mg twice daily and 40 mg twice daily) which showed effectiveness for the treatment of erosive esophagitis in clinical trials [see Clinical Studies (14.4)]. c In pediatric patients, the safety and effectiveness of famotidine tablets have not been established for the reduction of the risk of duodenal ulcer recurrence or for treatment of pathological hypersecretory conditions [see Use in Specific Populations (8.4)]. d Doses required to treat pathological hypersecretory conditions may exceed the maximum doses evaluated in patients with impaired renal function. The risk for increased adverse reactions in renally impaired patients treated with famotidine tablets for pathological hypersecretory conditions is unknown. e Recommended dosage regimen is 10 mg every other day. Since 20 mg or 40 mg tablet strength cannot be used for this dosage regimen, use an alternate famotidine formulation. 2.3 Administration Instructions Take famotidine tablets once daily before bedtime or twice daily in the morning and before bedtime, as recommended. Famotidine tablets may be taken with or without food [see Clinical Pharmacology (12.3)]. Famotidine tablets may be given with antacids.

Famotidine tablets are contraindicated in patients with a history of serious hypersensitivity reactions (e.g., anaphylaxis) to famotidine or other histamine-2 (H2) receptor antagonists.

1 Clinical Trial Experience Because clinical trials are conducted under widely varying conditions, adverse reaction rates observed in the clinical trials of a drug cannot be directly compared to rates in the clinical trials of another drug and may not reflect the rates observed in practice. Famotidine tablet was studied in 7 US and international placebo- and active-controlled trials in approximately 2500 patients [see Clinical Studies (14)]. A total of 1442 patients were treated with famotidine tablets, including 302 treated with40 mg twice daily, 456 treated with 20 mg twice daily, 461 treated with 40 mg once daily, and 396 treated with 20 mg once daily. The population was 17 to 91 years old, fairly well distributed between gender and race; however, the predominant race treated was Caucasian. The following adverse reactions occurred in greater than or equal to 1% of famotidine tablets-treated patients: headache, dizziness and constipation. The following other adverse reactions were reported in less than 1% of patients in clinical trials: Body as a Whole: fever, asthenia, fatigue Cardiovascular: palpitations Gastrointestinal: elevated liver enzymes, vomiting, nausea, abdominal discomfort, anorexia, dry mouth Hematologic: thrombocytopenia Hypersensitivity: orbital edema, rash, conjunctival injection, bronchospasm Musculoskeletal: musculoskeletal pain, arthralgia Nervous System/Psychiatric: seizure, hallucinations, depression, anxiety, decreased libido, insomnia, somnolence Skin: pruritus, dry skin, flushing Special Senses: tinnitus, taste disorder Other: impotence 6.2 Postmarketing Experience The following adverse reactions have been identified during post-approval use of famotidine. Because these reactions are reported voluntarily from a population of uncertain size, it is not always possible to reliably estimate their frequency or establish a causal relationship to drug exposure. Cardiovascular: arrhythmia, AV block, prolonged QT interval Gastrointestinal: cholestatic jaundice, hepatitis Hematologic: agranulocytosis, pancytopenia, leukopenia Hypersensitivity: anaphylaxis, angioedema, facial edema, urticaria Musculoskeletal: rhabdomyolysis, muscle cramps Nervous System/Psychiatric: confusion, agitation, paresthesia Respiratory: interstitial pneumonia Skin: toxic epidermal necrolysis/Stevens-Johnson syndrome

1 Drugs Dependent on Gastric pH for Absorption Famotidine can reduce the absorption of other drugs, due to its effect on reducing intragastric acidity, leading to loss of efficacy of the concomitant drug. Concomitant administration of famotidine tablets with dasatinib, delavirdine mesylate, cefditoren, and fosamprenavir is not recommended. See the prescribing information for other drugs dependent on gastric pH for absorption for administration instructions, including atazanavir, erlotinib, ketoconazole, itraconazole, ledipasvir/sofosbuvir, nilotinib, and rilpivirine. 7.2 Tizanidine (CYP1A2 Substrate) Although not studied clinically, famotidine is considered a weak CYP1A2 inhibitor and may lead to substantial increases in blood concentrations of tizanidine, a CYP1A2 substrate. Avoid concomitant use with famotidine tablets. If concomitant use is necessary, monitor for hypotension, bradycardia or excessive drowsiness. Refer to the full prescribing information for tizanidine.