Each film-coated tablet contains 10 mg memantine.
Pharmacology: Pharmacokinetics: Memantine is well absorbed after oral doses. Peak plasma concentrations are achieved in about 3 to 8 hours. Plasma protein binding is about 45%. Memantine undergoes partial hepatic metabolism. The main metabolites are N-3, 5-dimethylgludantan and 1-nitroso-3, 5-dimethyl-adamantane. The majority of a dose is excreted unchanged via the kidney; some active renal tubular secretion and reabsorption occurs. The terminal half-life ranges from 60 to 100 hours, under the alkaline conditions the rate of elimination is reduced.
For the treatment of Alzheimer's disease (moderate to severe, with or without dementia) and Parkinson's disease with dementia.
Memantine is a derivative of amantadine and is likewise antagonist of N-methyl-D-aspartate receptors. It is given by mouth as the hydrochloride. It can be taken with or without food.
The initial dose of memantine hydrochloride is 5 mg daily in the morning for the first week; this should be increased in weekly increments of 5 mg to a maximum dose of 20 mg daily. Dose of 10 mg daily and over should be taken in 2 divided doses. Reduced doses are recommended in patients with renal impairment. Clinical benefit should be reassessed on a regular basis.
Administration in renal impairment: In UK no dose adjustment is needed when memantine hydrochloride is given to patients with mild renal impairment. However, in those with moderate impairment (creatinine clearance 40 to 60 mL/minute per 1.73 m2) the maximum dose should be reduced to 10mg daily, no data are available for patients with severe impairment.
While in US, no dose reduction is required in those with mild to moderate impairment; a target dose of 10 mg is recommended in patients with severe impairment (creatinine clearance 5 to 29 mL /minute).
Patients with known hypersensitivity to memantine hydrochloride.
Dosage adjustment may be required in renal impairment but recommendations vary.
Only limited clinical data are also available for patients with recent myocardial infarction, uncompensated congestive heart failure and uncontrolled hypertension, use of memantine in these patients should be closely monitored. Seizures have occurred rarely and caution is recommended in patients at risk of convulsions.
Conditions that increase urinary pH eg, drastic changes in diet, renal tubular acidosis or severe infections of the urinary tract, may decrease elimination of memantine resulting in increased plasma levels; patient monitoring is recommended in such cases.
Pediatric Use: There are no adequate and well-controlled trials documenting the safety and efficacy of memantine in any illness occurring in children.
Pregnancy: There are no adequate and well-controlled studies of memantine in pregnant women. Memantine should be used during pregnancy only if the potential benefit justifies the potential risk to the fetus.
Nursing Mothers: It is not known whether memantine is excreted in human breast milk. Because many drugs are excreted in human milk, caution should be exercised when memantine is administered to a nursing mother.
Common adverse effects of memantine include constipation, dizziness, headache and somnolence. Less common reactions such as anxiety, hallucinations, confusion, abnormal gait, hypertonia, vomiting, cystitis and increased libido have also occurred.
Use of the other N-methyl-D-aspartate antagonist such as amantadine, ketamine or dextromethorphan with memantine may increase both the incidence and severity of adverse effects and should be avoided. The effects of dopaminergics and antimuscarinics may also be enhanced whereas memantine may reduce the actions of barbiturates and antipsychotics.
Memantine may alter the effects of antispasmodics baclofen and dantrolene. The clearance of memantine is reduced under alkaline urine conditions and drugs such as carbonic anhydrase inhibitors and sodium bicarbonate should be used with caution.
Store at temperatures not exceeding 30°C.
N06DX01 - memantine ; Belongs to the class of other anti-dementia drugs.