The recommended starting dose of Memantine HCl is 5 mg once daily. The dose should be increased in 5 mg increments to 10 mg/day (5 mg twice daily), 15 mg/day (5 mg and 10 mg as separate doses), and 20 mg/day (10 mg twice daily). The minimum recommended interval between dose increases is one week. The dosage shown to be effective in controlled clinical trials is 20 mg/day.
Memantine HCl can be taken with or without food. If a patient misses a single dose of Memantine HCl, that patient should not double up on the next dose. The next dose should be taken as scheduled.
If a patient fails to take Memantine HCl for several days, dosing may need to be resumed at lower doses and retitrated as described above.
Do not mix Memantine HCl oral solution with any other liquid. The oral solution is administered with a dosing device that comes with the drug and consists of a syringe, syringe adaptor cap, tubing and other supplies a patient needs to administer the drug. The supplied syringe should be used to withdraw the correct volume of oral solution and the oral solution should be slowly squirted into the corner of the patient's mouth.
Special Populations
Renal Impairment
A target dose of 5 mg twice daily is recommended in patients with severe renal impairment (creatinine clearance of 5 – 29 mL/min based on the Cockroft-Gault equation).
Hepatic Impairment
Memantine HCl should be administered with caution to patients with severe hepatic impairment [see Clinical Pharmacology (12.3)].