Namenda

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

See 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.