Ebixa

memantine

Ebixa (CA) (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

Oral solution: 2 mg/ml

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.

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.

• Instruct patient or caregiver not to mix solution with other liquids and to take or give oral solution only with included dosing device.

• Make sure patient or caregiver 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.

McGraw-Hill Nurse's Drug Handbook, 7th Ed. Copyright © 2013 by The McGraw-Hill Companies, Inc. All rights reserved

memantine

An NMDA (N-methyl D-aspartate) receptor antagonist that counters the toxic effects of glutamate excess to manage the symptoms of moderate to severe Alzheimer’s disease.

Adverse effects
Hallucinations, confusion, dizziness, headache, hypertonia, nausea, vomiting, constipation, hypertonia, cystitis, increased libido.
 
Proposed mechanism
Interferes with homocysteine binding at the NMDA receptor; homocysteine also mediates excitotoxicity, and disturbs glutamatergic neurotransmission.

Segen's Medical Dictionary. © 2012 Farlex, Inc. All rights reserved.

Ebixa

A brand name for MEMANTINE.

Collins Dictionary of Medicine © Robert M. Youngson 2004, 2005