memantine

Contraindicated in:

Hypersensitivity.

Use Cautiously in:

Severe renal impairment (↓ dose);
Severe hepatic impairment;
Concurrent use of other NMDA antagonists (amantadine, rimantadine, ketamine, dextromethorphan);
Concurrent use of drugs or diets that cause alkaline urine;
Conditions that ↑ urine pH including severe urinary tract infections or renal tubular acidosis (lead to ↓ excretion and ↑ levels);
OB: Safety not established in pregnancy;
Lactation: Use while breastfeeding only if potential maternal benefit justifies potential risk to infant;
Pedi: Safety and effectiveness not established in children.

Adv. Reactions/Side Effects ⬆ ⬇

CV: hypertension

Derm: rash

GI: diarrhea

GU: urinary frequency

Hemat: anemia

Metab: weight gain

Neuro: dizziness, fatigue, headache, sedation

Interactions ⬆ ⬇

Drug-drug:

Medications that urine pH (e.g. carbonic anhydrase inhibitors, sodium bicarbonate) may↓ excretion and ↑ levels and risk of toxicity.

Availability ⬆ ⬇

(Generic available)

Immediate-release tablets: 5 mg; 10 mg
Extended-release capsules: 7 mg; 14 mg; 21 mg; 28 mg
Oral solution, sugar-free, alcohol-freepeppermint: 2 mg/mL
In combination with: donepezil (Namzaric). See Appendix [not included in this PDA edition].

Route/Dosage ⬆ ⬇

PO (Adults ): Immediate-release: 5 mg once daily initially, ↑ at weekly intervals to 10 mg/day (5 mg twice daily), then 15 mg/day (5 mg once daily, 10 mg once daily as separate doses), then to target dose of 20 mg/day (10 mg twice daily); Extended-release: 7 mg once daily, ↑ at weekly intervals by 7 mg/day to target dose of 28 mg once daily.

Renal Impairment

(Adults ): CCr 5–29 mL/min: Immediate-release (solution): Target dose is 10 mg/day (5 mg twice daily); Extended-release: Target dose is 14 mg once daily.

US Brand Names ⬆ ⬇

~~Namenda,~~ ~~Namenda XR~~

Action ⬆ ⬇

Binds to CNS N-methyl-D-aspartate (NMDA) receptor sites, preventing binding of glutamate, an excitatory neurotransmitter.

Therapeutic effects:

Decreased symptoms of dementia/cognitive decline. Does not slow progression.
Cognitive enhancement.

Classifications ⬆ ⬇

Therapeutic Classification: anti-Alzheimers's agents

Pharmacologic Classification: n methyl d aspartate antagonist

Pharmacokinetics ⬆ ⬇

Absorption: Well absorbed after oral administration.

Distribution: Unknown.

Metabolism/Excretion: 57–82% excreted unchanged in urine by active tubular secretion moderated by pH dependent tubular reabsorption. Remainder metabolized; metabolites are not pharmacologically active.

Half-Life: 60–80 hr.

Canadian Brand Names ⬆ ⬇

Time/Action Profile ⬆ ⬇

(plasma concentrations)

ROUTE	ONSET	PEAK	DURATION
PO	unknown	3–7 hr	12 hr
PO-ER	unknown	9–12 hr	24 hr

Patient/Family Teaching ⬆ ⬇

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. If several days doses are missed, may need to resume at a lower dose and re-titrate up to previous dose; consult health care professional. Advise patient and caregiver to read Patient Instructions before starting and with each Rx refill in case of changes.
Caution patient and caregiver that memantine may cause dizziness. Monitor and assist with ambulation and caution patient to avoid driving and other activities requiring alertness until response to medication is known.
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.
Rep: Advise females of reproductive potential to notify health care professional if pregnancy is planned or suspected, or if breastfeeding.

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Indications ⬇

Contraind./Precautions ⬆ ⬇