memantine

memantine,

an anti-Alzheimer agent.

indications This drug is used to treat moderate to severe dementia in Alzheimer's disease.

contraindication Known hypersensitivity to this drug prohibits its use.

adverse effects Adverse effects of this drug include somnolence, headache, hallucinations, hypertension, vomiting, constipation, rash, coughing, dyspnea, back pain, fatigue, and pain. Common side effects include dizziness and confusion.

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memantine

Ebixa (UK), Namenda

Pharmacologic class: N-methyl-D-aspartate receptor antagonist (NMDA)

Therapeutic class: Anti-Alzheimer's agent

Pregnancy risk category B

Action

Unclear. Thought to act as a low- to moderate-affinity NMDA receptor antagonist, binding to NMDA receptor-operated channels. (Activation of these channels is thought to contribute to Alzheimer's symptoms.)

Availability

Tablets: 5 mg, 10 mg

Tablets (titration pack): 28 tablets of 5 mg and 21 tablets of 10 mg

⊘Indications and dosages

➣ Moderate to severe Alzheimer's-type dementia

Adults: Initially, 5 mg P.O. daily. Then titrate at intervals of at least 1 week in 5-mg increments, to a maximum of 10 mg P.O. b.i.d.

Dosage adjustment

• Moderate renal impairment

Contraindications

• Hypersensitivity to drug or its components

Precautions

Use cautiously in:
• neurologic conditions, moderate to severe renal impairment, genitourinary conditions that increase pH
• pregnant or breastfeeding patients.

Administration

• Give with or without food.

Route	Onset	Peak	Duration
P.O.	Unknown	3-7 hr	Unknown

Adverse reactions

CNS: dizziness, headache, syncope, aggressive reaction, confusion, somnolence, hallucinations, agitation, insomnia, vertigo, ataxia, abnormal gait, hypokinesia, anxiety, transient ischemic attack, cerebrovascular accident (CVA)

CV: hypertension, cardiac failure

EENT: cataract, conjunctivitis

GI: nausea, vomiting, diarrhea, constipation, anorexia

GU: frequent voiding, urinary incontinence, urinary tract infection

Hematologic: anemia

Musculoskeletal: back pain, arthralgia

Respiratory: cough, dyspnea, bronchitis, pneumonia

Skin: rash

Other: weight loss, fatigue, pain, falls, flulike symptoms, peripheral edema

Interactions

Drug-drug. Cimetidine, hydrochlorothiazide, nicotine, quinidine, ranitidine, triamterene: altered blood levels of both drugs

Urine-alkalizing drugs (carbonic anhydrase inhibitors, sodium bicarbonate): decreased memantine elimination

Drug-diagnostic tests. Alkaline phosphatase: increased level

Patient monitoring

☞ Check for heart failure and signs and symptoms of CVA.
• Monitor kidney function tests.

Patient teaching

• Tell patient to take with or without food.
• Make sure patient or caregiver knows exactly how drug should be taken and understands dose escalation.
• As appropriate, review all other significant and life-threatening adverse reactions and interactions, especially those related to the drugs and tests mentioned above.