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.
8.1 Pregnancy
Risk Summary
Available data with H 2-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 2000 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.
8.2 Lactation
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 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.
8.4 Pediatric Use
The safety and effectiveness of Famotidine have been established in pediatric patients for the treatment of peptic ulcer
disease (i.e., duodenal ulcer, gastric ulcer) and GERD (i.e., symptomatic nonerosive GERD, erosive esophagitis as
diagnosed by endoscopy). The use of Famotidine and the recommended dosage of Famotidine in these pediatric patients is
supported by evidence from adequate and well-controlled studies of Famotidine in adults and published pharmacokinetic and
pharmacodynamic data in pediatric patients [see Dosage and Administration (2.1), Clinical Pharmacology (12.2, 12.3)].
In pediatric patients, the safety and effectiveness for the treatment of pathological hypersecretory conditions and reduction
of risk of duodenal ulcer recurrence have not been established.
Famotidine 20 and 40 mg tablets are not recommended for use in pediatric patients weighing less than 40 kg because these
tablet strengths exceed the recommended dose for these patients [see Dosage and Administration (2.1)]. For pediatric
patients weighing less than 40 kg, consider another famotidine formulation (e.g., oral suspension, lower dose tablet).
8.5 Geriatric Use
Of the 1442 Famotidine -treated patients in clinical studies, approximately 10% were 65 and older. In these studies, no
overall differences in safety or effectiveness were observed between elderly and younger patients. In postmarketing
experience, CNS adverse reactions have been reported in elderly patients with and without renal impairment receiving
Famotidine [see Warnings and Precautions (5.1)].
Famotidine is known to be substantially excreted by the kidney, and the risk of adverse reactions to Famotidine may be
greater in elderly patients, particularly those with impaired renal function [see Use in Specific Populations (8.6)].
In general, use the lowest effective dose of Famotidine for an elderly patient and monitor renal function [see Dosage and
Administration (2.2)].
8.6 Renal Impairment
CNS adverse reactions and prolonged QT intervals have been reported in patients with moderate and severe renal
impairment [see Warnings and Precautions (5.1)]. The clearance of Famotidine is reduced in adults with moderate and
severe renal impairment compared to adults with normal renal function [see Clinical Pharmacology (12.3)]. No dosage
adjustment is needed in patients with mild renal impairment (creatinine clearance greater than or equal to 60 mL/minute).
Dosage reduction is recommended in adult and pediatric patients greater than or equal to 40 kg with moderate or severe
renal impairment (creatinine clearance less than 60 mL/minute) [see Dosage and Administration (2.2)].