NamendaKaren Anderson

MSNE 5356 Advanced Pharmacology

Memantine (Namenda)

• This medication is used to treat the pathophysiological condition of Alzheimer’s Disease. The drug classification of Namenda is an NMDA receptor antagonist, its primary treatment is for cognitive impairment and the daily recommended dose in milligrams is 5-20 (Vallerand & Sanoski, 2014).

Pathophysiology of Alzheimer’s • The pathophysiological condition of Alzheimer’s disease (AD) is

the most common cause of dementia with cases reported in approximately 80% of dementia.

• AD is diagnosed by clinicians based on pathologic changes in the brain namely the formation of neurofibrillary tangles, senile plaques, cortical atrophy as well as significant loss of neurons which cause a decrease in acetylcholine and excessive stimulation of glutamate leading to neuronal toxicity. The number one area affected by these changes is the brain. The areas of the brain responsible for memory, behavior, and motor skills which are the hippocampus cerebral cortex, and amygdala show steady deterioration (Arcangelo & Peterson, 2013).

Intended Drug Response• The intended drug response patients hope to experience while

taking Namenda is a decrease or slowing down of the progressive symptoms of Alzheimer’s disease.

• Pathologically a person with AD has high levels of glutamate which causes a decline in functionality. Namenda protects brain cells against the sustained onslaught of excess glutamate, thus decreasing symptomology (Townsend, 2015).

Potential Interactions

•Namenda has very low potential interactions according to Drugs.com. The minimal inhibition of isoenzymes due to the metabolism by the kidneys, lessens the potential for drug-drug interactions.

• (Source: http://www.drugs.com/namenda.html).

Adverse Drug Reactions

• According to Drugs.com, the major specific drug interaction for Namenda is to drugs that alkalize urine. PH of urine > 7 reduces the tubular clearance of Namenda by 80%, leading to accumulation of Namenda in the system causing adverse reactions.

• (Source: http://www.drugs.com/namenda.html).

Side Effects

• The side effects that are common with Namenda are dizziness, confusion, headache, and constipation (Source: http://www.drugs.com/namenda.html).

Pharmacokinetics

• The mechanism of Pharmacokinetics allows Namenda to be highly absorbed after oral administration. Which causes the drug to reach peak levels within three hours. The body’s absorption of Namenda is not effected by food. Because it undergoes minimal metabolism, approximately 70% is excreted unchanged in the urine (Source: http://www.drugs.com/namenda.html).

Drug Binding Issues• The major specific drug interaction for Namenda is to drugs

that alkalize urine. PH of urine > 7 reduces the tubular clearance of Namenda by 80%, leading to accumulation of Namenda in the system causing adverse reactions.

• The classification of potential adverse binding drugs and altered plasma concentration is greatest with Carbonic Anhydrase Inhibitors (e.g. Diamox, Daranide) and Sodium Bicarbonate (e.g. Antacid). Furthermore, the plasma protein bindings of Namenda is 45% which decreases the risk of interactions with medication such as Warfarin and Digoxin (Source: http://www.drugs.com/namenda.html).

Improving Communication

• The greatest outcome seen is established when multidisciplinary teams work together.

• Patients would benefit well if there was a database that could be updated by the patient or a caregiver that would be a comprehensive log of their medication. When prescribed new medication, each pharmacist would have the ability to access that log before dispensing medication in order to properly check for duplications, interactions, and allergies. The patient’s overall safety outcome would be improved substantially (Floroff, et. al).

Application to the Practice Setting• The majority of my patients are Geriatrics with neurocognitive

disorders especially Alzheimer’s disease. • Many patients have medication that is secreted by the kidneys and

they take many medications that affect urine PH. This knowledge will be applied to my daily education on their medications and I will be searching for use of antacids.

• Patient do not know or think that Tums or Rolaids are considered medication.

• I have a better insight into what medication can decrease the clearance of Namenda through the urine and which classification of medication interacts with Namenda.

References

• Arcangelo, V. P., & Peterson, A. M., (2013). Pharmacotherapeutics for advanced practice. A practical approach. (3rd ed.). Philadelphia, PA. Lippincott Williams and Wilkins.

• Drugs.com [Internet] Namenda information from Drugs.com. C 2000-15 [updated: 2015 September 30: cited 2015 November 10]. Available from http://www.drugs.com/monograph/namenda.html

• Floroff, C., Slattum, P., Harpe, S., Taylor, P., & Brophy, G. (n.d). Potentially Inappropriate Medication Use is Associated with Clinical Outcomes in Critically Ill Elderly Patients with Neurological Injury. Neurocritical Care, 21(3), 526-533.

• Vallerand, A. H., and Sanoski, C. A. (2014). Davis’s drug guide for nurses. (14th ed.). Valley Stream, NY. F. A. Davis Company.