The active ingredient in famotidine tablets, USP is a histamine-2 (H 2 ) receptor antagonist. Famotidine is N' -(aminosulfonyl)-3-[[[2-[(diaminomethylene)amino]-4-thiazolyl]methyl] thio]propanimidamide. The empirical formula of famotidine is C 8 H 15 N 7 O 2 S 3 and its molecular weight is 337.45. Its structural formula is: Each famotidine tablet, USP for oral administration contains either 20 mg or 40 mg of famotidine and the following inactive ingredients: corn starch, hypromellose, magnesium stearate, microcrystalline cellulose, sodium starch glycolate and film coating contains carnauba wax, hydroxypropyl cellulose, hypromellose, talc, titanium dioxide; and additionally 20 mg contains iron oxide red and iron oxide yellow. Famotidine, USP is a white to pale yellowish white crystalline powder that is freely soluble in dimethyl formamide, glacial acetic acid, slightly soluble in methanol, very slightly soluble in water, and practically insoluble in acetone, in alcohol, in chloroform, in ether and ethyl acetate. famotabstructure

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. Famotidine tablets are a histamine-2 (H 2 ) receptor antagonist indicated: In adult and pediatric patients 40 kg and greater for the treatment of: • active duodenal ulcer (DU). • active gastric ulcer. • symptomatic nonerosive gastroesophageal reflux disease (GERD). • erosive esophagitis due to GERD, diagnosed by biopsy. In adults for the: • treatment of pathological hypersecretory conditions (e.g., Zollinger-Ellison syndrome, multiple endocrine neoplasias). • reduction of the risk of DU recurrence.

• 20 mg tablets: Light yellow, round, biconvex, film-coated tablets debossed with “T” on one side and “11” on the other side. • 40 mg tablets: White, round, biconvex film-coated tablets debossed with “T” on one side and “12” on the other side. Tablets: 20 mg, 40 mg

Indication Recommended Dosage Adult and Pediatric Patients 40 kg and greater Active DU 40 mg once daily; or 20 mg twice daily Active Gastric Ulcer 40 mg once daily GERD 20 mg twice daily Erosive Esophagitis 20 mg twice daily; or 40 mg twice daily Adults Pathological Hypersecretory Conditions 20 mg every 6 hours; adjust to patient needs; maximum 160 mg every 6 hours Risk Reduction of DU Recurrence 20 mg once daily • See full prescribing information for complete dosing information, including dosing in renal impairment, and recommended treatment duration. Administration: • Take once daily before bedtime or twice daily in the morning and before bedtime with or without food

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 daily a Up to 8 weeks b,c Active gastric ulcer 40 mg once daily Up to 8 weeks c Symptomatic nonerosive GERD 20 mg twice daily Up to 6 weeks c Erosive esophagitis diagnosed by endoscopy 20 mg twice daily; or 40 mg twice daily a Up to 12 weeks Pathological hypersecretory conditions d 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 recurrence d 20 mg once daily 1 year c or as clinically indicated a Both dosages demonstrated effectiveness in clinical trials . 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 . c Longer treatment durations have not been studied in clinical trials . 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

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) . Table 2 shows the recommended maximum dosage of famotidine 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 day a Active gastric ulcer 20 mg once daily; or 40 mg every other day 20 mg every other day a Symptomatic nonerosive GERD 20 mg once daily 20 mg every other day a Erosive esophagitis diagnosed by endoscopy b 20 mg once daily; or 40 mg every other day b 20 mg every other day a,b 40 mg once daily b 20 mg once daily b Pathological hypersecretory conditions c Avoid use d Reduction of the risk of DU recurrence c 20 mg every other day a 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 . 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 . 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

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 . • Famotidine tablets may be given with antacids.

• Central Nervous System (CNS) Adverse Reactions: Elderly patients and patients with renal impairment at increased risk; reduce the dosage. ( 2.2 , 5.1 , 8.5 , 8.6 ) • GI Malignancy: Absence of GI symptoms does not preclude the presence of gastric malignancy; evaluate prior to initiating therapy. 5.1 Central Nervous System Adverse Reactions Central nervous system (CNS) adverse reactions, including confusion, delirium, hallucinations, disorientation, agitation, seizures, and lethargy, have been reported in elderly patients and patients with moderate and severe renal impairment treated with famotidine. 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

Concurrent Gastric Malignancy In adults, symptomatic response to therapy with famotidine does not preclude the presence of gastric malignancy. Consider evaluation for gastric malignancy in adult patients who have a suboptimal response or an early symptomatic relapse after completing treatment with famotidine.

• Drugs Dependent on Gastric pH for Absorption: Systemic exposure of the concomitant drug may be significantly reduced leading to loss of efficacy. See full prescribing information for a list of interacting drugs. • Tizanidine (CYP1A2) Substrate: Potential for substantial increases in blood concentrations of tizanidine resulting in hypotension, bradycardia or excessive drowsiness; avoid concomitant use, if possible

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 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

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. If concomitant use is necessary, monitor for hypotension, bradycardia or excessive drowsiness. Refer to the full prescribing information for tizanidine.