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Pharmacologic class: N-methyl-D-aspartate receptor antagonist (NMDA)
Therapeutic class: Anti-Alzheimer's agent
Pregnancy risk category B
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.)
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.
• Moderate renal impairment
• Hypersensitivity to drug or its components
Use cautiously in:
• neurologic conditions, moderate to severe renal impairment, genitourinary conditions that increase pH
• pregnant or breastfeeding patients.
• Give with or without food.
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
Musculoskeletal: back pain, arthralgia
Respiratory: cough, dyspnea, bronchitis, pneumonia
Other: weight loss, fatigue, pain, falls, flulike symptoms, peripheral edema
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
☞ Check for heart failure and signs and symptoms of CVA.
• Monitor kidney function tests.
• 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.
Namenda XR(trade name)
ClassificationTherapeutic: anti alzheimers agents
Pharmacologic: n methyl d aspartate antagonist
Time/action profile (blood levels)
|PO||unknown||3–7 hr||12 hr|
|PO-ER||unknown||9–12 hr||24 hr|
Adverse Reactions/Side Effects
Central nervous system
- weight gain
- urinary frequency
Drug-Drug interactionMedications that ↑ urine pH (e.g. carbonic anhydrase inhibitors, sodium bicarbonate ) may↓ excretion and ↑ blood levels.
Renal Impairment(Adults) CCr 5–29 mL/min—Immediate-release: Target dose is 10 mg/day (5 mg twice daily); Extended-release: Target dose is 14 mg once daily.
- Assess cognitive function (memory, attention, reasoning, language, ability to perform simple tasks) periodically during therapy.
- Lab Test Considerations: May cause anemia.
Potential Nursing DiagnosesDisturbed thought process (Indications)
Risk for injury (Side Effects)
Impaired environmental interpretation syndrome
- Dose increases should occur no more frequently than weekly.
- To switch from Namenda to Namenda XR, patients taking 10 mg twice daily of Namenda tablets may be switched to Namenda XR 28 mg once daily capsules the day following the last dose of a 10 mg Namenda tablet. Patients with renal impairment may use the same procedure to switch from Namenda 5 mg twice daily to Namenda XR 14 mg once daily.
- Oral: May be administered without regard to food.
- Administer oral solution using syringe provided. Do not dilute or mix with other fluids.
- Swallow extended release capsules whole; do not crush, chew, or divide. Capsules may be opened, sprinkled on applesauce, and swallowed. Entire contents of each capsule should be consumed; do not divide dose.
- Instruct patient and caregiver on how and when to administer memantine and how to titrate dose. Take missed doses as soon as remembered but not just before next dose; do not double doses. Advise patient and caregiver to read Patient Instructions sheet.
- Caution patient and caregiver that memantine may cause dizziness.
- Advise patient and caregiver to notify health care professional of all Rx or OTC medications, vitamins, or herbal products being taken and to consult with health care professional before taking other medications.
- Teach patient and caregivers that improvement in cognitive functioning may take months; degenerative process is not reversed.
- Improvement in neurocognitive decline (memory, attention, reasoning, language, ability to perform simple tasks) in patients with Alzheimer's disease.
memantineAn 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.
Hallucinations, confusion, dizziness, headache, hypertonia, nausea, vomiting, constipation, hypertonia, cystitis, increased libido.
Interferes with homocysteine binding at the NMDA receptor; homocysteine also mediates excitotoxicity, and disturbs glutamatergic neurotransmission.