Memantine Dosage

Medically reviewed by Drugs.com. Last updated on Aug 14, 2023.

Usual Adult Dose for Alzheimer's Disease

IMMEDIATE-RELEASE:
Week 1: 5 mg orally once a day.
Week 2: 10 mg orally/day (Administer 5 mg twice a day.)
Week 3: 15 mg orally/day (Administer 5 mg and 10 mg as separate doses.)
Week 4/Maintenance Dose: 20 mg orally/day (Administer 10 mg twice a day.)

EXTENDED-RELEASE:

• Initial Dose: 7 mg orally once a day.
• Maintenance and Maximum Dose: 28 mg orally once a day; increase the initial dose in 7 mg increments to the recommended maintenance dose.

Comments: The minimum recommended interval between dose increases is one week; only increase dosage if the previous dose has been well tolerated.

Use: Treatment of moderate to severe dementia of the Alzheimer's type.

Renal Dose Adjustments

• Mild and Moderate Renal Impairment (CrCl 30 to 80 mL/min): No adjustment recommended.
• Severe Renal Impairment (CrCl 5 to 29 mL/min): Immediate-Release: 5 mg orally twice a day; Extended-Release (Maintenance and Maximum Dose): 14 mg orally once a day.

Liver Dose Adjustments

• Mild and Moderate Hepatic Impairment (Child-Pugh A and B): No adjustment recommended.
• Severe Hepatic Impairment (Child-Pugh C): Immediate-Release: Use with caution; Extended-Release: Data not available.

Dose Adjustments

SWITCHING FROM IMMEDIATE-RELEASE (IR) TO EXTENDED RELEASE (XR):

• Patient on Regimen of 10 Mg IR Twice a Day: Switch to 28 mg XR once a day on the day following the last dose of the IR drug.
• Patients with Severe Renal Impairment (CrCl 5 to 29 mL/min): Switch to 14 mg XR once a day on the day following the last dose of the IR drug.
• Comments: There is no study data addressing the comparative efficacy of the 10 mg IR twice a day and 28 mg XR once a day regimens.

FAILING TO TAKE THE DRUG (IR or XR) FOR SEVERAL DAYS: Consider resuming treatment at a lower dose and re-titrate according to the standard titration scheme.

Precautions

Safety and efficacy have not been established in patients younger than 18 years.

Consult WARNINGS section for additional precautions.

Dialysis

Data not available.

Other Comments

Administration Advice:

• Administer this drug with or without food.
• In the event of a missed dose, advise patients to take the next dose as scheduled and not to double up on that dose.
• EXTENDED-RELEASE CAPSULES: May be opened and its contents sprinkled on applesauce; instruct patients to consume the entire contents of each capsule and not to divide the dose.
• EXTENDED-RELEASE CAPSULES: Except when opened and sprinkled on applesauce, advise patients to swallow the capsules whole and not to divide, chew, or crush them.
• ORAL SOLUTION: Consult the manufacturer product information for instructions on use of the dosing device that comes with this drug formulation.

Reconstitution/Preparation Techniques:

• ORAL SOLUTION: Do not mix with any other liquid; consult the manufacturer product information for preparation/handling instructions.

General:

• Overdosage: No specific antidote is available; use standard clinical procedures such as urine acidification, carbo medicinalis (interruption of potential entero-hepatic recirculation), gastric lavage, and forced diuresis as appropriate.
• ORAL SOLUTION: If using the bottle with the mounted pump, keep and transport the bottle in a vertical position.

Monitoring:

• Reassess the clinical benefit, tolerance, and dosing of this drug on a regular basis, preferably within 3 months after treatment initiation and according to current clinical guidelines thereafter.

Patient Advice:

• Avoid potentially dangerous activities such as driving and operating machinery until you know how this drug affects you.

Further information

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.

Medical Disclaimer