Famotidine precautions

List of precautions
General Patients with moderate/severe renal insufficiency Carcinogenesis Mutagenesis Impairment of fertility Pregnancy Nursing mothers Pediatrics (<1 year of age) Pediatrics (1-16 year of age) Geriatric use

General
Symptomatic response to therapy with Famotidine does not preclude the presence of gastric malignancy. Return to top

Patients with moderate/severe renal insufficiency
Since CNS adverse effects have been reported in patients with moderate and severe renal insufficiency, longer intervals between doses or lower doses may need to be used in patients with moderate (creatinine clearance < 50 mL/min) or severe (creatinine clearance < 10 mL/min) renal insufficiency to adjust for the longer elimination half-life of Famotidine. Return to top

Carcinogenesis
In a 106 week study in rats and a 92 week study in mice given oral doses of up to 2000 mg/kg/day (approximately 2500 times the recommended human dose for active duodenal ulcer), there was no evidence of carcinogenic potential for Famotidine. Return to top

Mutagenesis
Famotidine was negative in the microbial mutagen test (Ames test) using Salmonella typhimurium and Escherichia coli with or without rat liver enzyme activation at concentrations up to 10,000 mcg/plate. In in vivo studies in mice, with a micronucleus test and a chromosomal aberration test, no evidence of a mutagenic effect was observed. Return to top

Impairment of fertility
In studies with rats given oral doses of up to 2000 mg/kg/day or intravenous doses of up to 200 mg/kg/day, fertility and reproductive performance were not affected. Return to top

Pregnancy
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 I.V. 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 (250 times the usual human dose) 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. Return to top
 * Pregnancy category B.

Nursing mothers
Studies performed in lactating rats have shown that Famotidine is secreted into breast milk. Transient growth depression was observed in young rats suckling from mothers treated with maternotoxic doses of at least 600 times the usual human dose. Famotidine is detectable in human milk. Because of the potential for serious adverse reactions in nursing infants from Famotidine, a decision should be made whether to discontinue nursing or discontinue the drug, taking into account the importance of the drug to the mother. Return to top

Pediatrics (<1 year of age)
Use of Famotidine in pediatric patients <1 year of age is supported by evidence from adequate and well-controlled studies of Famotidine in adults, and by two studies in pediatric patients <1 year of age. These studies suggest that a starting dose of 0.5 mg/kg/dose of Famotidine oral suspension may be of benefit for the treatment of GERD for up to 4 weeks once daily in patients <3 months of age and twice daily in patients 3 months to <1 year of age; the safety and benefit of Famotidine treatment beyond 4 weeks have not been established. Famotidine should be considered for the treatment of GERD only if conservative measures (e.g., thickened feedings) are used concurrently and if the potential benefit outweighs the risk. Return to top

Pediatrics (1-16 year of age)
Use of Famotidine in pediatric patients 1 to 16 years of age is supported by evidence from adequate and well-controlled studies of Famotidine in adults, and by studies in pediatric patients. These studies suggest a starting dose for pediatric patients 1 to 16 years of age as follows: While published uncontrolled studies suggest effectiveness of Famotidine in the treatment of gastroesophageal reflux disease and peptic ulcer, data in pediatric patients are insufficient to establish percent response with dose and duration of therapy. Therefore, treatment duration (initially based on adult duration recommendations) and dose should be individualized based on clinical response and/or pH determination (gastric or esophageal) and endoscopy. Published uncontrolled clinical studies in pediatric patients have employed doses up to 1 mg/kg/day for peptic ulcer and 2 mg/kg/day for GERD with or without esophagitis including erosions and ulcerations. Return to top
 * Peptic ulcer: 0.5 mg/kg/day p.o. at bedtime or divided b.i.d. up to 40 mg/day.
 * Gastroesophageal Reflux Disease with or without esophagitis including erosions and ulcerations: 1.0mg/kg/day p.o. divided b.i.d. up to 40 mg b.i.d.

Geriatric use
Of the 4,966 subjects in clinical studies who were treated with Famotidine, 488 subjects (9.8%) were 65 and older, and 88 subjects (1.7%) were greater than 75 years of age. No overall differences in safety or effectiveness were observed between these subjects and younger subjects. However, greater sensitivity of some older individuals cannot be ruled out. No dosage adjustment is required based on age. This drug is known to be substantially excreted by the kidney, and the risk of toxic reactions to this drug may be greater in patients with impaired renal function. Because elderly patients are more likely to have decreased renal function, care should be taken in dose selection, and it may be useful to monitor renal function. Dosage adjustment in the case of moderate or severe renal impairment is necessary. Return to top