Memantine

Memantine (中文: 美金剛)is a glutamate receptor antagonist. It is used to treat moderate to severe Alzheimer’s disease.

藥名

Generic Name 藥名	HA Code 藥物代碼	Classification藥物分類
Memantine HCL Tablet 10mg	MEMA01	P1S1S3

Mechanism of Action

Glutamate receptor antagonist

Dosage

By Oral: initially 5 mg once daily, increased in steps of 5 mg at weekly intervals to a maximum dose of 20 mg daily.

Clinical benefit should be assessed on a regular basis.

Side Effects

Common side effects include

• Constipation
• Dizziness
• Headache
• Hallucinations
• confusuion
• sleepiness

Serious side effects may include:

• Blood clots
• Psychosis
• Heart failure

Pharmacokinetics

Oral bioavailability	Memantine is well absorbed after oral doses. It is about 45% bound to plasma proteins.
Onset of action	Peak plasma concentrations are achieved in 3 to 8 hours
Metabolism	Partial hepatic metabolism.
Elimination half-life	Ranges from 60 to 100 hours

How long does it take for donepezil to take effect?

Donepezil may take as long as 12 weeks to begin working.

What time of day should donepezil be taken?

It is usually taken once a day with or without food, just before bedtime. Take donepezil at around the same time every day.

Why is donepezil taken at night?

Donepezil is taken at night because it can cause irregular or slow heartbeat for some patients, which can cause fainting. When it is taken at bedtime, affected patients will be able to sleep through those side effects.

Drug Management

Monitoring

• No routine monitoring required for toxicity

Monitoring Efficacy

• Activities of daily living and cognitive functioning improvements
• Slowing in the progression of decline in cognitive function and memory impairment
• It may take months for any noticeable improvement

Caution

• Genitourinary conditions: Conditions that raise urine pH may decrease the urinary elimination of memantine
• Hepatic impairment: Precaution use in severe hepatic impairment; effects of impairment on pharmacokinetics have not been established

Contraindications

It is contraindicated in patients with a known hypersensitivity to memantine.

FAQ

How should I take Memantine hydrochloride ?

Memantine hydrochloride should be administered orally once a day. To benefit from your medicine you should take it daily around the same time. The tablets should be swallowed with plenty of water. The tablets can be taken with or without food.

What should I avoid while taking?

Avoid abruptly discontinue the medication.

What happen if I overdose?

Contact your primary care doctor. If emergency situation, call 999

What happen if I miss a dose?

Take it as soon as you remember. If it is near the time of the next dose, skip the missed dose. Take your next dose at the regular time. Do not double the dose to catch up.