"Today, the U.S. Food and Drug Administration issued a proposal designed to assist companies developing new treatments for patients in the early stages of Alzheimer's disease, before the onset of noticeable (overt) dementia.
Conditions that raise urine pH may decrease the urinary elimination of memantine resulting in increased plasma levels of memantine.
NAMENDA XR (memantine hydrochloride extended release capsules) has not been systematically evaluated in patients with a seizure disorder. In clinical trials of memantine, seizures occurred in 0.3% of patients treated with memantine and 0.6% of patients treated with placebo.
Patient Counseling Information
See FDA-approved patient labeling.
To assure safe and effective use of NAMENDA XR (memantine hydrochloride extended release capsules) , the information and instructions provided in the patient information section should be discussed with patients and caregivers.
Patients and caregivers should be instructed to take NAMENDA XR (memantine hydrochloride extended release capsules) only once per day, as prescribed.
Patients and caregivers should be instructed that NAMENDA XR (memantine hydrochloride extended release capsules) capsules be swallowed whole. Alternatively, NAMENDA XR (memantine hydrochloride extended release capsules) capsules may be opened and sprinkled on applesauce and the entire contents should be consumed. The capsules should not be divided, chewed or crushed.
Patients and caregivers should be advised that the product may cause headache, diarrhea and dizziness.
Carcinogenesis, Mutagenesis, Impairment of Fertility
There was no evidence of carcinogenicity in a 113-week oral study in mice at doses up to 40 mg/kg/day (7 times the maximum recommended human dose [MRHD] on a mg/m2 basis). There was also no evidence of carcinogenicity in rats orally dosed at up to 40 mg/kg/day for 71 weeks followed by 20 mg/kg/day (14 and 7 times the MRHD on a mg/m2 basis, respectively) through 128 weeks.
Memantine produced no evidence of genotoxic potential when evaluated in the in vitro S. typhimurium or E. coli reverse mutation assay, an in vitro chromosomal aberration test in human lymphocytes, an in vivo cytogenetics assay for chromosome damage in rats, and the in vivo mouse micronucleus assay. The results were equivocal in an in vitro gene mutation assay using Chinese hamster V79 cells.
No impairment of fertility or reproductive performance was seen in rats administered up to 18 mg/kg/day (6 times the MRHD on a mg/m2 basis) orally from 14 days prior to mating through gestation and lactation in females, or for 60 days prior to mating in males.
Use In Specific Populations
Pregnancy Category B: There are no adequate and well-controlled studies of NAMENDA XR (memantine hydrochloride extended release capsules) in pregnant women. NAMENDA XR (memantine hydrochloride extended release capsules) should be used during pregnancy only if the potential benefit justifies the potential risk to the fetus.
Memantine given orally to pregnant rats and pregnant rabbits during the period of organogenesis was not teratogenic up to the highest doses tested (18 mg/kg/day in rats and 30 mg/kg/day in rabbits, which are 6 and 21 times, respectively, the maximum recommended human dose [MRHD] on a mg/m2 basis).
Slight maternal toxicity, decreased pup weights and an increased incidence of non-ossified cervical vertebrae were seen at an oral dose of 18 mg/kg/day in a study in which rats were given oral memantine beginning pre-mating and continuing through the postpartum period. Slight maternal toxicity and decreased pup weights were also seen at this dose in a study in which rats were treated from day 15 of gestation through the post-partum period. The no-effect dose for these effects was 6 mg/kg, which is 2 times the MRHD on a mg/m2 basis.
It is not known whether memantine is excreted in human milk. Because many drugs are excreted in human milk, caution should be exercised when memantine is administered to a nursing mother.
The safety and effectiveness of memantine in pediatric patients have not been established.
Last reviewed on RxList: 7/22/2010
This monograph has been modified to include the generic and brand name in many instances.
Additional Namenda XR Information
Report Problems to the Food and Drug Administration
You are encouraged to report negative side effects of prescription drugs to the FDA. Visit the FDA MedWatch website or call 1-800-FDA-1088.
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