APO-MEMANTINE

What it is

APO-MEMANTINE contains memantine hydrochloride 10 mg in film-coated tablets. A 20 mg film-coated tablet formulation is also available. Memantine is a rapid, strongly voltage-dependent, uncompetitive NMDA receptor antagonist.

Approved indications

— Treatment of the symptoms of moderately severe to severe Alzheimer's disease.

Dosing overview

The recommended maintenance dose is 20 mg per day, achieved by upward titration of 5 mg per week. Titration begins with 5 mg daily in week 1, increases to 10 mg daily in week 2, 15 mg daily in week 3, and reaches the maintenance dose of 20 mg daily from week 4 onwards. In patients with moderate renal impairment (creatinine clearance 30–49 mL/min), the daily dose should be 10 mg per day, and if tolerated well after at least 7 days of treatment, the dose can be increased up to 20 mg/day according to the standard titration scheme. In patients with severe renal impairment (creatinine clearance 5–29 mL/min), the daily dose should be 10 mg per day. APO-MEMANTINE should be administered once a day at the same time every day, taken with a little liquid, with or without food.

Key safety warnings

Memantine is contraindicated in patients with epilepsy, and caution is recommended in patients with a former history of convulsions or patients with predisposing factors for epilepsy. Animal studies have reported adverse effects of memantine on the visual system, including abnormal lysosomal storage in retinal cells at systemic exposures 10-fold clinical exposure, lens opacity at 20-fold clinical exposure, and corneal clouding in dogs and baboons at exposures near or below clinical exposure. Ophthalmological examinations in clinical studies did not disclose ocular changes in the double-blind period, though cataract was reported in 6% of patients treated with memantine for 12 months compared to 3% who received placebo for 6 months then memantine for 6 months (p=0.3059). In most clinical trials, patients with recent myocardial infarction, uncompensated congestive heart failure, and uncontrolled hypertension were excluded, so only limited data are available and patients with these conditions should be closely supervised. Some factors that may raise urinary pH, including drastic changes in diet from carnivorous to vegetarian, massive ingestion of alkalising gastric buffers, renal tubular acidosis, or severe urinary tract infections with Proteus bacteria, may necessitate careful monitoring of the patient.

Contraindications

APO-MEMANTINE is contraindicated in patients with hypersensitivity to either the active ingredient or any of the excipients, and in patients with a current seizure disorder or with any history of seizures.

PBS listing

The 20 mg tablet is listed on the PBS with a streamlined and authority required restriction, with an ex-manufacturer price of A$28.09.

Regulatory history

APO-MEMANTINE 10 mg tablet was first listed on the ARTG on 29 January 2010, and the 20 mg tablet formulation was first listed on 24 April 2014.