- Shake the bottle of constituted famotidine, USP suspension vigorously for 5 to 10 seconds prior to each use.
- Take famotidine for oral suspension, USP once daily before bedtime or twice daily in the morning and before bedtime, as recommended.
- Famotidine for oral suspension, USP may be taken with or without food [see Clinical Pharmacology (12.3)].
- Famotidine for oral suspension, USP may be given with antacids.
- Store the constituted suspension at 25°C (77°F). Protect from freezing. Discard unused constituted suspension after 30 days.
Pediatric Patients Less Than One Year of Age
In a clinical study in 35 pediatric patients less than 1 year of age with GERD symptoms, two patients discontinued due to adverse reactions. Agitation observed in 5 patients resolved when famotidine was discontinued [see Use in Specific Populations (8.4)].
Risk Summary
Available data with H2-receptor antagonists, including famotidine, in pregnant women are insufficient to establish a drug-associated risk of major birth defects, miscarriage or adverse maternal or fetal outcomes. In animal reproduction studies, no adverse development effects were observed with oral administration of famotidine at doses up to approximately 243 and 122 times, respectively, the recommended human dose of 80 mg per day for the treatment of erosive esophagitis (see Data).
The estimated background risk for major birth defects and miscarriage for the indicated population is unknown. All pregnancies have a background risk of birth defect, loss, or other adverse outcomes. In the U.S. general population, the background risk of major birth defects and miscarriage in clinically recognized pregnancies is 2% to 4% and 15% to 20%, respectively.
Data
Animal Data
Reproductive studies have been performed in rats and rabbits at oral doses of up to 2,000 and 500 mg/kg/day, respectively, and in both species at intravenous doses of up to 200 mg/kg/day and have revealed no significant evidence of impaired fertility or harm to the fetus due to famotidine. While no direct fetotoxic effects have been observed, sporadic abortions occurring only in mothers displaying marked decreased food intake were seen in some rabbits at oral doses of 200 mg/kg/day (about 49 times the recommended human dose of 80 mg per day, based on body surface area) or higher. There are, however, no adequate or well-controlled studies in pregnant women. Because animal reproductive studies are not always predictive of human response, this drug should be used during pregnancy only if clearly needed.
Risk Summary
There are limited data available on the presence of famotidine in human breast milk. There were no effects on the breastfed infant. There are no data on famotidine effects on milk production. Famotidine is present in the milk of lactating rats (see Data).
The developmental and health benefits of breastfeeding should be considered along with the mother's clinical need for famotidine and any potential adverse effects on the breastfed child from famotidine for oral suspension or from the underlying maternal condition.
Data
Animal Data
Transient growth depression was observed in young rats suckling from mothers treated with maternotoxic doses of famotidine at least 600 times the usual human dose.
Peptic Ulcer Disease and GERD With or Without Esophagitis and Ulcerations
Pediatric Patients One Year to Less than 17 Years of Age
The safety and effectiveness of famotidine for oral suspension have been established in pediatric patients 1 year to less than 17 years of age for the treatment of peptic ulcer disease and GERD with or without esophagitis and ulcerations. Use of famotidine in this age group is supported by evidence from adequate and well-controlled studies of famotidine in adults with additional pharmacokinetic and pharmacodynamic data in pediatric patients 1 year to less than 17 years of age [see Dosage and Administration (2.1), Clinical Pharmacology (12.2, 12.3)]. The safety and effectiveness of famotidine for oral suspension for the treatment of peptic ulcer disease in pediatric patients less than one year of age have not been established.
GERD
Pediatric Patients Less Than One Year of Age
The safety and effectiveness of famotidine for oral suspension have been established in pediatric patients from birth to less than 1 year of age for the treatment of GERD. The use of famotidine this is age group is supported by evidence from adequate and well-controlled studies of famotidine in adults and with supportive data in pediatric patients from birth to less than 1 year of age [see Dosage and Administration (2.1), Clinical Pharmacology (12.2, 12.3), Clinical Studies (14.7)].
Other Conditions
The safety and effectiveness for the treatment of pathological hypersecretory conditions and reduction of risk of duodenal ulcer recurrence have not been established in pediatric patients.
A safe and effective dosage has not been established in pediatric patients with renal impairment.
Adults
Famotidine inhibited both basal and nocturnal gastric secretion, as well as secretion stimulated by food and pentagastrin. After oral administration of famotidine, the onset of the antisecretory effect occurred within one hour; the maximum effect was dose-dependent, occurring within one to three hours. Duration of inhibition of secretion by doses of 20 mg and 40 mg was 10 hours to 12 hours.
Single evening oral doses of 20 mg and 40 mg inhibited basal and nocturnal acid secretion in all subjects; mean nocturnal gastric acid secretion was inhibited by 86% and 94%, respectively, for a period of at least 10 hours. The same doses given in the morning suppressed food-stimulated acid secretion in all subjects. The mean suppression was 76% and 84%, respectively, 3 to 5 hours after administration, and 25% and 30%, respectively, 8 to 10 hours after administration. In some subjects who received the 20 mg dose, however, the antisecretory effect was dissipated within 6 hours to 8 hours. There was no cumulative effect with repeated doses. The nocturnal intragastric pH was raised by evening doses of 20 mg and 40 mg of famotidine to mean values of 5.0 and 6.4, respectively. When famotidine was given after breakfast, the basal daytime interdigestive pH at 3 and 8 hours after 20 mg or 40 mg of famotidine was raised to about 5.
Famotidine had little or no effect on fasting or postprandial serum gastrin levels. Gastric emptying and exocrine pancreatic function were not affected by famotidine.
In clinical pharmacology studies, systemic effects of famotidine in the CNS, cardiovascular, respiratory, or endocrine systems were not noted. Also, no anti-androgenic effects were noted. Serum hormone levels, including prolactin, cortisol, thyroxine (T4), and testosterone, were not altered after treatment with famotidine.
Pediatric Patients
Pharmacodynamics of famotidine, assessed by gastric pH, were evaluated in 5 pediatric patients 2 years to 13 years of age using the sigmoid Emax model. These data suggest that the relationship between serum concentration of famotidine and gastric acid suppression is similar to that observed in adults (see Table 4).
Table 4: Serum Concentrations of Famotidine Associated with Gastric Acid Reduction in Famotidine-Treated Pediatric and Adult Patients | EC50 (ng/mL) Using the Sigmoid Emax model, serum concentrations of famotidine associated with 50% maximum gastric acid reduction are presented as means ± SD. |
|---|
| Pediatric Patients | 26 ± 13 |
| Adults | |
| Healthy adult subjects | 26.5 ± 10.3 |
| Adult patients with upper GI bleeding | 18.7 ± 10.8 |
In a study examining the effect of famotidine on gastric pH and duration of acid suppression in pediatric patients, four pediatric patients ages 11 to 15 years of age using the oral formulation at a dose of 0.5 mg/kg, maintained a gastric pH above 5 for 13.5 ± 1.8 hours.
Absorption
Famotidine is incompletely absorbed. The bioavailability of oral doses is 40% to 45%. Bioavailability may be slightly increased by food, or slightly decreased by antacids; however, these effects are of no clinical consequence.
Peak famotidine plasma levels occur in 1 to 3 hours. Plasma levels after multiple dosages are similar to those after single doses.
Distribution
Fifteen to 20% of famotidine in plasma is protein bound.
Elimination
Metabolism
Famotidine undergoes minimal first-pass metabolism. Twenty-five to 30% of an oral dose was recovered in the urine as unchanged compound. The only metabolite identified in humans is the S-oxide.
Excretion
Famotidine has an elimination half-life of 2.5 to 3.5 hours. Famotidine is eliminated by renal (65% to 70%) and metabolic (30% to 35%) routes. Renal clearance is 250 to 450 mL/minute, indicating some tubular excretion.
Specific Populations
Pediatric Patients
Infants from birth to 12 Months
After a single oral dose administration of 0.5 mg/kg orally in patients from birth to 12 months, the bioavailability is approximately 42%.
The AUC increased 1.4-fold after single oral dose of 1 mg/kg compared to 0.5 mg/kg and 2.7-fold after multiple oral doses of 1 mg/kg compared to 0.5 mg/kg.
Plasma clearance is reduced and elimination half-life is prolonged in pediatric patients from birth to 3 months of age compared to older pediatric patients. Following intravenous administration of 0.5 mg/kg, CLTotal was 0.13 ± 0.06 L/hr/kg, 0.21 ± 0.06 L/hr/kg, and 0.49 ± 0.17 L/hr/kg in pediatric patients <1 month of age, <3 months of age, and >3 to 12 months of age, respectively. Elimination half-life was 10.5 hours, 8.1 hours, and 4.5 hours in pediatric patients <1 month of age, <3 months of age, and >3 to 12 months of age, respectively.
Patients 11 Years to 15 Years
The mean bioavailability in 8 pediatric patients was 50% compared to adult values of 42% to 49%.
Pharmacokinetic parameters in pediatrics 11 years to 15 years is compared to infants from birth to 12 months in Table 5.
Table 5: Mean Pharmacokinetic Parameters Following a Single Oral Dose of 0.5 mg/kg in Infants and Pediatric Patients | Infants from Birth to 12 months (N=5) | Pediatric Patients 11 Years to 15 Years (N=8) |
|---|
| AUC0-∞ (ng∙hr/mL) arithmetic mean ± S.D. | 645 ± 249 | 580 ± 60 |
| Cmax (ng/mL) | 79.2 | 97.3 |
| Tmax (hr) median | 2.0 (1/0, 4.1) observed minimum and maximum values | 2.3 (2.1, 2.9) reported minimum and maximum values |
| T1/2 (hr) | 5.82 | 2.13 |
Patients with Renal Impairment
In adult patients with severe renal impairment (creatinine clearance less than 30 mL/minute), the systemic exposure (AUC) of famotidine increased at least 5-fold. In adult patients with moderate renal impairment (creatinine clearance between 30 to 60 mL/minute), the AUC of famotidine increased at least 2-fold [see Dosage and Administration (2.3), Use in Specific Populations (8.6)].
Drug Interaction Studies
Human Organic Anion Transporter (OAT) 1 and 3: In vitro studies indicate that famotidine is a substrate for OAT1 and OAT3. Following coadministration of probenecid (1,500 mg), an inhibitor of OAT1 and OAT3, with a single oral 20 mg dose of famotidine in 8 healthy subjects, the serum AUC0-10h of famotidine increased from 424 to 768 ng∙hr/mL and the maximum serum concentration (Cmax) increased from 73 to 113 ng/mL. Renal clearance, urinary excretion rate and amount of famotidine excreted unchanged in urine were decreased. The clinical relevance of this interaction is unknown.
Multidrug and Toxin Extrusion Protein 1 (MATE-1): An in vitro study showed that famotidine is an inhibitor of MATE-1. However, no clinically significant interaction with metformin, a substrate for MATE-1, was observed.
CYP1A2: Famotidine is a weak CYP1A2 inhibitor.
Central Nervous System (CNS) Adverse Reactions
Advise elderly patients and those with moderate and severe renal impairment of the risk of CNS adverse reactions, including confusion, delirium, hallucinations, disorientation, agitation, seizures, and lethargy [see Warnings and Precautions (5.1)]. Report symptoms immediately to a healthcare provider.
QT Prolongation
Advise patients with moderate and severe renal impairment of the risk of QT interval prolongation [see Use in Specific Populations (8.6)]. Report new cardiac symptoms, such as palpitations, fainting and dizziness or lightheadedness immediately to a healthcare provider.
Administration
Advise patients to take and caregivers to administer:
- Famotidine once daily before bedtime or twice daily in the morning and before bedtime, as recommended.
Advise patients and caregivers:
- Famotidine may be taken with or without food.
- Famotidine may be given with antacids.
Distributed by
UPSHER-SMITH LABORATORIES, LLC
Maple Grove, MN 55369
200635
Revised: 12/2022