"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.
Because of their pharmacological action, cholinesterase inhibitors have vagotonic effects on the sinoatrial and atrioventricular nodes, leading to bradycardia and AV block. Bradycardia and all types of heart block have been reported in patients both with and without known underlying cardiac conduction abnormalities. Therefore, all patients should be considered at risk for adverse effects on cardiac conduction.
Patients treated with galantamine up to 24 mg/day using the recommended dosing schedule showed a dose-related increase in risk of syncope (placebo 0.7% [2/286]; 4 mg BID 0.4% [3/692]; 8 mg BID 1.3% [7/552]; 12 mg BID 2.2% [6/273]).
Through their primary action, cholinomimetics may be expected to increase gastric acid secretion due to increased cholinergic activity. Therefore, patients should be monitored closely for symptoms of active or occult gastrointestinal bleeding, especially those with an increased risk for developing ulcers, e.g., those with a history of ulcer disease or patients using concurrent nonsteroidal anti-inflammatory drugs (NSAIDs). Clinical studies of galantamine have shown no increase, relative to placebo, in the incidence of either peptic ulcer disease or gastrointestinal bleeding.
Galantamine, as a predictable consequence of its pharmacological properties, has been shown to produce nausea, vomiting, diarrhea, anorexia, and weight loss. During therapy, the patient's weight should be monitored [see ADVERSE REACTIONS].
Although this was not observed in clinical trials with galantamine, cholinomimetics may cause bladder outflow obstruction.
Seizures: Cholinesterase inhibitors are believed to have some potential to cause generalized convulsions. However, seizure activity may also be a manifestation of Alzheimer's disease. In clinical trials, there was no increase in the incidence of convulsions with galantamine compared to placebo. Patients with Alzheimer's disease should be monitored closely for seizures while taking galantamine.
Because of its cholinomimetic action, galantamine should be prescribed with care to patients with a history of severe asthma or obstructive pulmonary disease. Respiratory function should be monitored closely for the occurrence of respiratory adverse effects.
Deaths in Subjects with Mild Cognitive Impairment (MCI)
In two randomized placebo controlled trials of 2 years duration in subjects with mild cognitive impairment (MCI), a total of 13 subjects on galantamine (n=1026) and 1 subject on placebo (n=1022) died. The deaths were due to various causes which could be expected in an elderly population; about half of the galantamine deaths appeared to result from various vascular causes (myocardial infarction, stroke, and sudden death).
Although the difference in mortality between galantamine- and placebo-treated groups in these two studies was significant, the results are highly discrepant with other studies of galantamine. Specifically, in these two MCI studies, the mortality rate in the placebo-treated subjects was markedly lower than the rate in placebo-treated patients in trials of galantamine in Alzheimer's disease or other dementias (0.7 per 1000 person years compared to 22-61 per 1000 person years, respectively). Although the mortality rate in the galantamine-treated MCI subjects was also lower than that observed in galantamine-treated patients in Alzheimer's disease and other dementia trials (10.2 per 1000 person years compared to 23-31 per 1000 person years, respectively), the relative difference was much less. When the Alzheimer's disease and other dementia studies were pooled (n=6000), the mortality rate in the placebo group numerically exceeded that in the galantamine group. Furthermore, in the MCI studies, no subjects in the placebo group died after 6 months, a highly unexpected finding in this population.
Individuals with mild cognitive impairment demonstrate isolated memory impairment greater than expected for their age and education, but do not meet current diagnostic criteria for Alzheimer's disease.
Carcinogenesis, Mutagenesis, Impairment of Fertility
In a 24-month oral carcinogenicity study in rats, an increase in endometrial adenocarcinomas was observed at 10 mg/kg/day (4 times the MRHD of 24 mg/day on a mg/m² basis or 6 times on a plasma exposure [AUC] basis) and 30 mg/kg/day (12 times MRHD on a mg/m² basis or 19 times on an AUC basis). No increase in neoplastic changes was observed in females at 2.5 mg/kg/day (equivalent to the MRHD on a mg/m² basis or 2 times on an AUC basis) or in males up to the highest dose tested of 30 mg/kg/day (12 times the MRHD on a mg/m² and AUC basis).
Galantamine was not carcinogenic in a 6-month carcinogenicity study in transgenic (P 53-deficient) mice at oral doses up to 20 mg/kg/day, or in a 24-month carcinogenicity study in mice at oral doses up to 10 mg/kg/day (equivalent to the MRHD on a plasma AUC basis).
Impairment of Fertility
No impairment of fertility was seen in rats given up to 16 mg/kg/day (7 times the MRHD on a mg/m² basis) for 14 days prior to mating in females and for 60 days prior to mating in males.
Use In Specific Populations
Pregnancy Category C
There are no adequate and well-controlled studies in pregnant women. In studies conducted in animals, administration of galantamine during pregnancy resulted in developmental toxicity (increased incidence of morphological abnormalities and decreased growth in offspring) at doses similar to or greater than those used clinically. RAZADYNE® ER and RAZADYNE® should be used during pregnancy only if the potential benefit justifies the potential risk to the fetus.
In rats, administration of galantamine (oral doses of 2, 8, or 16 mg/kg/day), from day 14 (females) or day 60 (males) prior to mating and continuing in females through the period of organogenesis, resulted in an increased incidence of fetal skeletal variations at the two highest doses. The no-effect dose for embryo-fetal developmental toxicity in rats (2 mg/kg/day) is approximately equal to the maximum recommended human dose (MRHD of 24 mg/day) on a body surface area (mg/m²) basis. When galantamine (oral doses of 4, 12, 28, or 48 mg/kg/day) was administered to pregnant rabbits throughout the period of organogenesis, small increases in fetal visceral malformations and skeletal variations were observed at the highest dose. The no-effect dose for embryo-fetal developmental toxicity in rabbits (28 mg/kg/day) is approximately 20 times the MRHD on a mg/m² basis. In a study in which pregnant rats were orally dosed with galantamine (2, 8, or 16 mg/kg/day) from the beginning of organogenesis through day 21 post-partum, pup weights were decreased at birth and during the lactation period at the two highest doses. The no-effect dose for pre- and postnatal developmental toxicity in rats (2 mg/kg/day) is approximately equal to the MRHD on a mg/m² basis.
It is not known whether this drug is excreted in human milk. Because many drugs are excreted in human milk, caution should be exercised when RAZADYNE® ER and RAZADYNE® is administered to a nursing woman.
The safety and effectiveness in pediatric patients have not been established.
Alzheimer's disease is a disorder occurring primarily in individuals over 55 years of age. Seven double-blind, placebo-controlled clinical trials and 5 open-label trials in a total of 4474 patients have investigated RAZADYNE® ER and RAZADYNE® in the treatment of mild to moderate dementia of the Alzheimer's type [see ADVERSE REACTIONS and Clinical Studies]. The mean age of patients enrolled in these clinical studies was 75 years; 78% of these patients were between 65 and 84 years of age, and 11% of patients were 85 years of age or older.
In patients with moderately impaired hepatic function, dose titration should proceed cautiously [see CLINICAL PHARMACOLOGY and DOSAGE AND ADMINISTRATION]. The use of RAZADYNE® ER and RAZADYNE® in patients with severe hepatic impairment is not recommended.
In patients with moderately impaired renal function, dose titration should proceed cautiously [see CLINICAL PHARMACOLOGY and DOSAGE AND ADMINISTRATION]. In patients with severely impaired renal function (CLcr < 9 mL/min) the use of RAZADYNE® ER and RAZADYNE® is not recommended.
Last reviewed on RxList: 8/6/2013
This monograph has been modified to include the generic and brand name in many instances.
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