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Pharmacology · chapter 10 · Drugs to Treat Myasthenia Gravis and Alzheimer’s Disease

Alzheimer’s Drugs

The 14 things this section of the textbook says that you are most likely to be asked about — quoted word for word, not retold. Then 6 practice questions with the reasoning.

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Key points

  1. How AChE inhibitors work

    AChE inhibitors bind to and interfere with the enzyme AChE. This enzyme is responsible for the destruction of ACh. By inhibiting this enzyme, more internally released ACh is available for use within cholinergic synapses.

  2. They slow, not stop, the disease

    Treatment with AChE inhibitors does not stop the progression of AD but reduces how quickly neurons are destroyed.

  3. Donepezil's long half-life

    An important pharmacokinetic note is that donepezil is highly protein bound (96%); therefore, it has a prolonged half-life of 70 hours. This means that it takes an estimated 15 days for the drug to reach steady state.

  4. Galantamine and skin reactions

    Adverse effects are the same as for donepezil with the addition of potential life-threatening skin reactions, such as Stevens–Johnson syndrome. Clients and caregivers should stop the drug and report any signs of a skin rash to their health care provider.

  5. Rivastigmine GI effects and the patch

    Peripheral cholinergic effects, such as nausea, vomiting, diarrhea, and anorexia, occur more frequently with this drug. Blood levels are lower when using the transdermal route; therefore, the intensity of adverse effects is decreased.

  6. Rivastigmine and body weight

    Rivastigmine blood levels vary with weight; careful titration and monitoring should be performed in clients with low or high body weights.

  7. GI effects are most common

    Many of the adverse effects caused by AChE inhibitors relate to the stimulation of the PSNS. GI effects are the most common, including nausea, vomiting, diarrhea, abdominal pain, increased salivation, and anorexia.

  8. Cardiac suppression

    These drugs can cause cardiac-suppressive effects, which can result in symptomatic bradycardia, heart block, and even cardiac arrest.

  9. Breathing in asthma and COPD

    AChE inhibitor drugs can also impair breathing in those with pulmonary disorders, such as asthma and chronic obstructive pulmonary disease (COPD), due to bronchoconstriction and increased bronchial secretions. Frequent monitoring of the breathing pattern is required.

  10. Peptic ulcer contraindication

    Contraindications include peptic ulcer disease because these drugs increase the secretion of hydrochloric acid in the stomach, which can worsen the ulcer and potentially cause perforation and/or bleeding.

  11. Avoid anticholinergic drugs

    Any drugs with anticholinergic effects—such as first-generation histamine-1 receptor antagonists (H1RAs), conventional antipsychotics, and tricyclic antidepressants (TCAs)—should not be used concurrently because they will reduce or block therapeutic effects of cholinergic agonists.

  12. Beta blockers and digoxin

    Clients taking drugs such as beta blockers (propranolol/metoprolol) or digoxin should be especially careful of significant bradycardia because they both cause negative chronotropic effects.

  13. Memantine and urine pH

    Any condition or drug that raises urinary pH to 8 or more can reduce drug elimination by 80% (see drug interactions and caution in Table 10.7), which will result in the accumulation of memantine within the plasma and increase the risk of adverse effects.

  14. Treatment is not a cure

    Emphasize that treatment is not a cure and will not reverse signs or symptoms and usually will only produce modest benefits.

Terms to know

Donepezil
Donepezil, a centrally acting reversible cholinesterase inhibitor, is used primarily for treatment of mild to severe forms of AD.
Memantine
Memantine is an antagonist of the NMDA receptor subtype of the glutamate receptor.
Glutamate
Glutamate is the primary excitatory amino acid in the CNS.

Practice questions

Stuck on select-all-that-apply? How to take them one option at a time.

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  1. A client with Alzheimer's disease takes donepezil and metoprolol. Which assessment finding is most important for the nurse to report?

    1. Mild nausea after meals
    2. Occasional headache
    3. Heart rate of 48 beats per minute with dizziness
    4. Increased salivation

    Answer: Heart rate of 48 beats per minute with dizziness

    AChE inhibitors can cause symptomatic bradycardia, and beta blockers add a negative chronotropic effect, so a slow heart rate with symptoms is the priority. Nausea, salivation and headache are expected, less dangerous cholinergic effects.

  2. A client with Alzheimer's disease has a history of an active peptic ulcer. The provider is considering donepezil. Why should the nurse question this order?

    1. Donepezil causes constipation that aggravates ulcers.
    2. Donepezil must be crushed, which irritates the ulcer.
    3. Donepezil is absorbed poorly when an ulcer is present.
    4. Donepezil increases stomach acid secretion and can worsen the ulcer.

    Answer: Donepezil increases stomach acid secretion and can worsen the ulcer.

    Peptic ulcer disease is a contraindication because AChE inhibitors increase hydrochloric acid secretion, which can worsen the ulcer and cause perforation or bleeding. The other options describe effects not supported by the section.

  3. A nurse is teaching the caregiver of a client starting a rivastigmine transdermal patch. Which instructions should the nurse include? Select all that apply.

    1. Apply a new patch right away if one falls off.
    2. Use the same site every day so the skin gets used to it.
    3. Remove the previous day's patch before applying a new one.
    4. Cut the patch in half if nausea occurs.
    5. Apply the patch to the upper or lower back.

    Answer: Apply a new patch right away if one falls off., Remove the previous day's patch before applying a new one., Apply the patch to the upper or lower back.

    Only one patch is worn at a time, the back helps prevent inadvertent removal, and a patch that falls off is replaced immediately. The same site should not be reused for 14 days, and a cut or altered patch must not be used.

  4. A client taking galantamine develops a new skin rash. What should the nurse tell the caregiver?

    1. Give the drug with food to prevent the rash.
    2. Stop the drug and report the rash to the health care provider.
    3. Apply a moisturizer and continue the drug.
    4. The rash is expected and will fade in a few weeks.

    Answer: Stop the drug and report the rash to the health care provider.

    Galantamine can cause potentially life-threatening skin reactions such as Stevens-Johnson syndrome, so the drug is stopped and the rash reported. Continuing the drug or treating the rash as expected delays care for a dangerous reaction.

  5. A client is starting donepezil for Alzheimer's disease. Which teaching points should the nurse include? Select all that apply.

    1. Change positions slowly.
    2. Double the next dose if a dose is missed.
    3. Take donepezil at bedtime.
    4. Take the medication with food to decrease gastric irritation.
    5. Stop the drug if memory does not improve in a week.

    Answer: Change positions slowly., Take donepezil at bedtime., Take the medication with food to decrease gastric irritation.

    Donepezil is taken at bedtime, with food to reduce gastric irritation, and the client rises slowly because of possible orthostatic hypotension. Stopping abruptly makes symptoms quickly return, and a missed dose is not doubled.

  6. A family member asks the nurse what to expect from donepezil for their mother with Alzheimer's disease. Which response is accurate?

    1. It is not a cure and usually gives only modest benefits.
    2. It will reverse her memory loss.
    3. It stops the disease from progressing.
    4. It cures the disease if started early.

    Answer: It is not a cure and usually gives only modest benefits.

    The nurse emphasizes that treatment is not a cure, will not reverse symptoms and usually produces modest benefits. AChE inhibitors reduce how quickly neurons are destroyed but do not stop progression.

Where every quote comes from

Section 10.4 Alzheimer’s Drugs of Pharmacology for Nurses by Tina Barbour-Taylor, Leah Mueller (Sabato), Donna Paris, Dorie Weaver, OpenStax, 2024. Read the whole section free at openstax.org.

The textbook is licensed under CC BY-NC-SA 4.0. This page quotes it word for word and adds the headings, the order and the practice questions; references to the book's figures and stray spaces left by its formatting are removed. The page is shared under the same licence. Nothing here is sold.