Memantine Hcl Side Effects

6.1 Clinical Trials Experience Memantine hydrochloride was evaluated in eight double-blind placebo-controlled trials involving a total of 1862 dementia (Alzheimer’s disease, vascular dementia) patients (940 patients treated with memantine hydrochloride and 922 patients treated with placebo) for a treatment period up to 28 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 clinical practice.

Adverse Events Leading to Discontinuation In placebo-controlled trials in which dementia patients received doses of memantine hydrochloride up to 20 mg/day, the likelihood of discontinuation because of an adverse reaction was the same in the memantine hydrochloride group (10.1%) as in the placebo group (11.5%).

No individual adverse reaction was associated with the discontinuation of treatment in 1% or more of memantine hydrochloride-treated patients and at a rate greater than placebo.

Most Common Adverse Reactions In double-blind placebo-controlled trials involving dementia patients, the most common adverse reactions (incidence ≥ 5% and higher than placebo) in patients treated with memantine hydrochloride were dizziness, headache, confusion and constipation.

Table 1 lists all adverse reactions that occurred in at least 2% of patients treated with memantine hydrochloride and at an incidence greater than placebo.

Table 1: Adverse Reactions Reported in Controlled Clinical Trials in at Least 2% of Patients Receiving Memantine hydrochloride and at a Higher Frequency than Placebo-treated Patients Adverse Reaction Placebo (N = 922) % Memantine hydrochloride (N = 940) % Body as a Whole Fatigue 1 2 Pain 1 3 Cardiovascular System Hypertension 2 4 Central and Peripheral Nervous System Dizziness 5 7 Headache 3 6 Gastrointestinal System Constipation 3 5 Vomiting 2 3 Musculoskeletal System Back pain 2 3 Psychiatric Disorders Confusion 5 6 Somnolence 2 3 Hallucination 2 3 Respiratory System Coughing 3 4 Dyspnea 1 2 The overall profile of adverse reactions and the incidence rates for individual adverse reactions in the subpopulation of patients with moderate to severe Alzheimer’s disease were not different from the profile and incidence rates described above for the overall dementia population.

Seizures Memantine hydrochloride has not been systematically evaluated in patients with a seizure disorder.

In clinical trials of memantine hydrochloride, seizures occurred in 0.2% of patients treated with memantine hydrochloride and 0.5% of patients treated with placebo.

6.2 Postmarketing Experience The following adverse reactions have been identified during post-approval use of memantine.