Alzheimer's Disease Medications: Nursing Pharmacology Study Guide

Alzheimer's disease medications do not cure the disease — they slow symptom progression. Nurses must know the two main drug classes, how they differ by disease stage, the cholinergic side-effect pattern they produce, and the safety/monitoring rules that show up repeatedly on the NCLEX.

Drug Classes at a Glance

Mechanism of Action

• Cholinesterase inhibitors block the enzyme that breaks down acetylcholine, increasing acetylcholine levels and improving nerve cell communication. Donepezil, rivastigmine, and galantamine all belong to this class.
• Memantine is an NMDA receptor antagonist that regulates glutamate activity and prevents excess calcium from entering nerve cells (which would otherwise cause cell death).
• Memantine is often combined with donepezil for advanced stages.

Uses by Stage

• Donepezil — approved for mild, moderate, AND severe Alzheimer's (all stages).
• Rivastigmine — mild to moderate Alzheimer's and Parkinson's dementia.
• Galantamine — mild to moderate Alzheimer's.
• Memantine — moderate to severe Alzheimer's.
• Combination therapy (donepezil + memantine) — for better symptom control in advanced disease.

Side Effects (Most Tested)

• Cholinesterase inhibitors commonly cause: nausea, vomiting, diarrhea, bradycardia, syncope, weight loss, insomnia, and muscle cramps.
• Rivastigmine causes the most GI side effects of the three — using the patch reduces these effects.
• Memantine commonly causes dizziness, headache, constipation, and confusion.
• Mnemonic for cholinesterase effects — "SLUDGE": Salivation, Lacrimation, Urination, Defecation, GI upset, Emesis. (Milder with these drugs than with true cholinergic agonists.)

Labs and Monitoring

• Monitor heart rate and blood pressure before and during therapy.
• Assess for bradycardia, especially in patients with pre-existing heart conditions.
• Monitor weight regularly due to risk of weight loss.
• Assess cognitive function using tools such as the MMSE.
• Rivastigmine patch: check skin for irritation/rash and rotate application sites (abdomen, back, chest, upper arms).
• Memantine: assess renal function — CrCl < 30 requires dose reduction.

Contraindications & Cautions

• Cholinesterase inhibitors — use cautiously in patients with sick sinus syndrome or other cardiac conduction defects, peptic ulcer disease, asthma, COPD, and urinary obstruction.
• Memantine — use cautiously in severe renal impairment and seizure disorders.
• Anticholinergic drugs (diphenhydramine/Benadryl, oxybutynin, tolterodine) counteract cholinesterase inhibitors and should be avoided.

Pregnancy Safety

• All Alzheimer drugs have limited human data — use only if clearly needed.

Nursing Safety Rules & High-Yield NCLEX Notes

• Cholinesterase inhibitors are most effective in early stages and do not cure the disease — they only slow symptom progression.
• Give donepezil at bedtime to minimize GI upset, but watch for insomnia.
• The rivastigmine patch is preferred for patients who cannot swallow or have severe GI side effects.
  • Remove the old patch before applying a new one to avoid overdose.
  • Rotate sites to prevent skin irritation.
• Monitor for bradycardia and syncope, especially when starting therapy or increasing the dose.
• Use NSAIDs cautiously due to increased gastric acid and ulcer risk.
• Memantine can be given with or without food, may be opened and sprinkled on applesauce if swallowing is difficult, and is given in the morning to prevent insomnia.
• Avoid anticholinergic drugs — they cancel out cholinesterase inhibitor effects.
• Cholinesterase inhibitors prolong the effects of succinylcholine during surgery. Hold donepezil before elective surgery if possible, and always inform the anesthesiologist.
• Galantamine was renamed from Reminyl to Razadyne to avoid confusion with Amaryl (a diabetes drug).
• Do not stop these drugs abruptly — cognitive decline may worsen.
• Donepezil is the only cholinesterase inhibitor approved for all stages of Alzheimer's.

One-Page Rapid Summary

• Alzheimer medications are either cholinesterase inhibitors (donepezil, rivastigmine, galantamine) or NMDA receptor antagonists (memantine).
• Cholinesterase inhibitors ↑ acetylcholine → mild to moderate Alzheimer's. Memantine regulates glutamate → moderate to severe stages.
• Side effects: cholinesterase inhibitors → nausea, vomiting, diarrhea, bradycardia, weight loss. Memantine → dizziness, headache, constipation. Rivastigmine causes the most GI side effects (patch reduces them).
• Monitor HR for bradycardia, weight, renal function for memantine, and rotate rivastigmine patch sites. Avoid anticholinergics. Cholinesterase inhibitors prolong succinylcholine paralysis.
• Donepezil is the only drug approved for all stages and is safest in renal impairment. Never stop abruptly. These drugs slow progression but do not cure Alzheimer's disease.

Key takeaways

• Cholinesterase inhibitors (donepezil, rivastigmine, galantamine) treat mild–moderate disease; memantine treats moderate–severe disease.
• Donepezil is the only agent approved for all stages and is preferred when renal function is impaired.
• Watch for bradycardia, syncope, GI upset, and weight loss with cholinesterase inhibitors — think SLUDGE.
• Memantine requires dose reduction when CrCl < 30 and is dosed in the morning to limit insomnia.
• Avoid anticholinergics (they antagonize the drug effect), and hold donepezil before surgery because it prolongs succinylcholine.
• Never stop abruptly — cognitive decline can rapidly worsen.