SIDE EFFECTS

Clinical Trial Data Sources

NAMENDA XR (memantine hydrochloride extended release capsules) was evaluated in a double-blind placebo-controlled trial treating a total of 676 patients with moderate to severe dementia of the Alzheimer's type (341 patients treated with NAMENDA XR (memantine hydrochloride extended release capsules) 28 mg/day dose and 335 patients treated with placebo) for a treatment period up to 24 weeks.

Because clinical trials are conducted under widely varying conditions, adverse reaction rates observed in the clinical trials of a drug cannot be directly compared to rates in the clinical trials of another drug and may not reflect the rates observed in practice.

Adverse Reactions Leading to Discontinuation

In the placebo-controlled clinical trial of NAMENDA XR (see Clinical Studies), which treated a total of 676 patients, the proportion of patients in the NAMENDA XR 28 mg/day dose and placebo groups who discontinued treatment due to adverse events were 10.0% and 6.3%, respectively. The most common adverse reaction in the NAMENDA XR (memantine hydrochloride extended release capsules) treated group that led to treatment discontinuation in this study was dizziness at a rate of 1.5%.

Most Common Adverse Reactions

The most commonly observed adverse reactions seen in patients administered NAMENDA XR (memantine hydrochloride extended release capsules) in the controlled clinical trial, defined as those occurring at a frequency of at least 5% in the NAMENDA XR (memantine hydrochloride extended release capsules) group and at a higher frequency than placebo were headache, diarrhea and dizziness.

Table 1 lists treatment-emergent adverse reactions that were observed at an incidence of ≥ 2% in the NAMENDA XR (memantine hydrochloride extended release capsules) treated group and occurred at a rate greater than placebo.

Table 1: Adverse reactions observed with a frequency of ≥ 2% and occurring with a rate greater than placebo

Vital Sign Changes

NAMENDA XR (memantine hydrochloride extended release capsules) and placebo groups were compared with respect to (1) mean change from baseline in vital signs (pulse, systolic blood pressure, diastolic blood pressure, and weight) and (2) the incidence of patients meeting criteria for potentially clinically significant changes from baseline in these variables. There were no clinically important changes in vital signs in patients treated with NAMENDA XR (memantine hydrochloride extended release capsules) . A comparison of supine and standing vital sign measures for NAMENDA XR (memantine hydrochloride extended release capsules) and placebo in Alzheimer's patients indicated that NAMENDA XR (memantine hydrochloride extended release capsules) treatment is not associated with orthostatic changes.

Laboratory Changes

NAMENDA XR (memantine hydrochloride extended release capsules) and placebo groups were compared with respect to (1) mean change from baseline in various serum chemistry, hematology, and urinalysis variables and (2) the incidence of patients meeting criteria for potentially clinically significant changes from baseline in these variables. These analyses revealed no clinically important changes in laboratory test parameters associated with NAMENDA XR (memantine hydrochloride extended release capsules) treatment.

ECG Changes

NAMENDA XR (memantine hydrochloride extended release capsules) and placebo groups were compared with respect to (1) mean change from baseline in various ECG parameters and (2) the incidence of patients meeting criteria for potentially clinically significant changes from baseline in these variables. These analyses revealed no clinically important changes in ECG parameters associated with NAMENDA XR (memantine hydrochloride extended release capsules) treatment.

Other Adverse Reactions Observed During Clinical Trials of NAMENDA XR (memantine hydrochloride extended release capsules)

Following is a list of treatment-emergent adverse reactions reported from 750 patients treated with NAMENDA XR (memantine hydrochloride extended release capsules) for periods up to 52 weeks in double-blind or open-label clinical trials. The listing does not include those events already listed in Table 1, those events for which a drug cause was remote, those events for which descriptive terms were so lacking in specificity as to be uninformative, and those events reported only once which did not have a substantial probability of being immediately life threatening. Events are categorized by body system.

Blood and Lymphatic System Disorders: anemia.

Cardiac Disorders: bradycardia, myocardial infarction.

Gastrointestinal Disorders: fecal incontinence, nausea.

General Disorders: asthenia, fatigue, gait disturbance, irritability, peripheral edema, pyrexia.

Infections and Infestations: bronchitis, nasopharyngitis, pneumonia, upper respiratory tract infection, urinary tract infection.

Injury, Poisoning and Procedural Complications: fall.

Investigations: weight decreased.

Metabolism and Nutrition Disorders: anorexia, dehydration, decreased appetite, hyperglycemia.

Musculoskeletal and Connective Tissue Disorders: arthralgia, pain in extremity.

Nervous System Disorders: convulsion, dementia Alzheimer's type, syncope, tremor.

Psychiatric Disorders: agitation, confusional state, delirium, delusion, disorientation, hallucination, insomnia, restlessness.

Respiratory, Thoracic and Mediastinal Disorders: cough, dyspnea.

Memantine Immediate Release Clinical Trial and Post Marketing Spontaneous Reports

The following additional adverse reactions have been identified from previous worldwide experience with memantine (immediate release) use. These adverse reactions have been chosen for inclusion because of a combination of seriousness, frequency of reporting, or potential causal connection to memantine and have not been listed elsewhere in labeling. However, because some of these adverse reactions were reported voluntarily from a population of uncertain size, it is not always possible to reliably estimate their frequency or establish a causal relationship between their occurrence and the administration of memantine. These events include:

Blood and Lymphatic System Disorders: agranulocytosis, leukopenia (including neutropenia), pancytopenia, thrombocytopenia. thrombotic thrombocytopenic purpura.

Cardiac Disorders: atrial fibrillation, atrioventricular block (including 2nd and 3rd degree block), cardiac failure, orthostatic hypotension, and torsades de pointes.

Endocrine Disorders: inappropriate antidiuretic hormone secretion.

Gastrointestinal disorders: colitis, pancreatitis.

General disorders and administration site conditions: malaise, sudden death.

Hepatobiliary Disorders: hepatitis (including abnormal hepatic function test, cytolytic and cholestatic hepatitis), hepatic failure.

Infections and infestations: sepsis.

Investigations: electrocardiogram QT prolonged, international normalized ratio increased.

Metabolism and Nutrition Disorders: hypoglycaemia, hyponatraemia.

Nervous System Disorders: convulsions (including grand mal), cerebrovascular accident, dyskinesia, extrapyramidal disorder, hypertonia, loss of consciousness, neuroleptic malignant syndrome, Parkinsonism, tardive dyskinesia, transient ischemic attack.

Psychiatric Disorders: hallucinations (both visual and auditory), restlessness, suicidal ideation.

Renal and Urinary Disorders: acute renal failure (including abnormal renal function test), urinary retention.

Skin Disorders: rash, Stevens Johnson syndrome.

Vascular Disorders: pulmonary embolism, thrombophlebitis, deep venous thrombosis.

The following adverse events have been reported to be temporally associated with memantine treatment and are not described elsewhere in the product labeling: aspiration pneumonia, bone fracture, carpal tunnel syndrome, cerebral infarction, chest pain, cholelithiasis, claudication, depressed level of consciousness (including rare reports of coma), dysphagia, encephalopathy, gastritis, gastroesophageal reflux, intracranial hemorrhage, hyperglycemia, hyperlipidemia, ileus, impotence, lethargy, myoclonus, supraventricular tachycardia, and tachycardia. However, there is again no evidence that any of these additional adverse events are caused by memantine.

Read the entire FDA prescribing information for Namenda XR (Memantine Hydrochloride Extended Release Capsules) »