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Pharmacology · chapter 11 · Drugs to Treat Parkinson’s Disease and Multiple Sclerosis

Anti-Parkinsonian 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. Drugs relieve symptoms only

    Although pharmacologic management is a first-line treatment, drugs only provide symptomatic relief; they do not cease or reverse the neuronal degeneration.

  2. Anhidrosis and heat stroke

    Anhidrosis can occur from the decreased secretion from sweat glands. This can be dangerous because the body is unable to release heat, which can lead to hyperthermia or heat stroke.

  3. Anticholinergics and glaucoma

    Blockade of cholinergic receptors in the eye may precipitate or aggravate glaucoma because it increases the aqueous humor in the anterior chamber by disrupting the exit of the fluid.

  4. Avoid with obstruction or BPH

    If a client has any type of intestinal or urinary obstruction, like benign prostatic hypertrophy, these medications should be avoided because they will worsen the condition.

  5. Anticholinergics in older adults

    Anticholinergic drugs are designated as potentially inappropriate for use in adults 65 years and older because older adults are very sensitive to the adverse effects like orthostatic hypotension, urinary retention, constipation, and tachycardia.

  6. Why levodopa needs carbidopa

    Levodopa is not used as a monotherapy; given alone, it is not beneficial. It should be administered with carbidopa (discussed later in this chapter).

  7. Take on an empty stomach

    This drug should be taken on an empty stomach, typically 30 minutes before a meal. Food can significantly decrease absorption, especially a large amount of protein.

  8. Wearing off

    Wearing off” develops near the end of the dosing interval, indicating drug levels have declined to a subtherapeutic value.

  9. Impulse control problems

    This drug can cause clients to become impulsive. Clients may either begin to engage in or increase already existing gambling/sexual urges or uncontrolled spending.

  10. Never stop levodopa abruptly

    Importantly, the drug should not be stopped abruptly because it could lead to the reemergence of signs and symptoms of PD, sometimes worse than the initial manifestations. It could also lead to confusion, muscle rigidity, autonomic instability, and hyperpyrexia, which resembles neuroleptic malignant syndrome (NMS).

  11. Nonselective MAOIs and levodopa

    Nonselective monoamine oxidase inhibitors (MAOIs) can result in a hypertensive crisis if administered to a client taking levodopa. Nonselective MAOIs should be withdrawn at least 2 weeks before starting levodopa.

  12. Sudden sleep with dopamine agonists

    Often the person will not feel drowsy before falling asleep. This creates an elevated risk of injury and/or accidents.

  13. Tyramine and selegiline at high doses

    This crisis can be triggered by taking sympathomimetic drugs and by ingesting foods containing tyramine. High levels of tyramine are found in foods that are aged, cured, or fermented (DailyMed, Selegiline Hydrochloride, 2023).

  14. Tolcapone and the liver

    Tolcapone should be reserved for clients who cannot be treated adequately with safer drugs. This drug can cause severe, sometimes fatal, hepatocellular injury.

Terms to know

ballismus
Some of these are just bothersome (head bobbing tics, grimacing), whereas others can be disabling, such as ballismus —rapid, involuntary jerking or flinging of proximal muscle groups—or choreoathetosis —slow, involuntary, writhing movements.
Levodopa
Levodopa is a metabolic precursor of dopamine and is inactive until it undergoes conversion to its active state.
Carbidopa
Carbidopa is a dopamine decarboxylase inhibitor; combined with levodopa, levodopa’s effects are enhanced.
Hyperhidrosis
Hyperhidrosis (excessive sweating unrelated to heat or exercise) is caused by the dysregulation of the autonomic nervous system, which could be related to PD or the dopamine agonist.
livedo reticularis
Clients who take amantadine for more than 1 month often develop livedo reticularis, which is characterized by purple mottling of the skin.

Practice questions

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

The graded version needs JavaScript. Every question is below anyway, with the answer and why.

Every question here, with the answer

  1. A client with Parkinson's disease takes carbidopa/levodopa. The client asks when to take it in relation to meals. What should the nurse teach?

    1. Take it with a large high-protein meal.
    2. Take it on an empty stomach, about 30 minutes before a meal.
    3. Take it with an iron supplement to boost absorption.
    4. Take it with a glass of milk at bedtime.

    Answer: Take it on an empty stomach, about 30 minutes before a meal.

    Carbidopa/levodopa is taken on an empty stomach, about 30 minutes before a meal, because food, especially a large amount of protein, significantly decreases absorption. Iron salts form chelates with levodopa and reduce its bioavailability.

  2. A client who has taken carbidopa/levodopa for several years says, "The tremor comes back about an hour before my next dose is due." How should the nurse interpret this?

    1. It is the wearing-off phenomenon from subtherapeutic drug levels.
    2. It shows the drug should be stopped at once.
    3. It is an allergic reaction to carbidopa.
    4. It is livedo reticularis.

    Answer: It is the wearing-off phenomenon from subtherapeutic drug levels.

    Wearing off develops near the end of the dosing interval, when drug levels have declined to a subtherapeutic value. Stopping levodopa abruptly is dangerous, and the other options do not describe this pattern.

  3. A client is starting pramipexole, a dopamine agonist. Which teaching points should the nurse include? Select all that apply.

    1. The drug is safe to take while breastfeeding.
    2. Stop the drug right away if you feel dizzy.
    3. You may fall asleep suddenly during daily activities without feeling drowsy.
    4. Report new urges to gamble or spend money.
    5. Rise slowly from sitting or lying down.

    Answer: You may fall asleep suddenly during daily activities without feeling drowsy., Report new urges to gamble or spend money., Rise slowly from sitting or lying down.

    Dopamine agonists can cause sudden sleep attacks, compulsive behaviors and orthostatic hypotension. They should not be stopped abruptly because this worsens PD symptoms, and they should not be taken during pregnancy or breastfeeding.

  4. An older adult client with Parkinson's disease and benign prostatic hypertrophy is prescribed an anticholinergic. Which finding should concern the nurse most?

    1. Suprapubic distention with small voids
    2. Mild sensitivity to bright light
    3. Improved hand tremor
    4. Mild dry mouth

    Answer: Suprapubic distention with small voids

    Anticholinergics cause urinary retention and should be avoided in urinary obstruction such as benign prostatic hypertrophy, so signs of retention need action. Reduced tremor is the goal, and dry mouth and light sensitivity are expected, manageable effects.

  5. A client taking an anticholinergic for Parkinson's disease is going home in the summer. Which instructions should the nurse give? Select all that apply.

    1. Keep sugarless hard candy or gum on hand for dry mouth.
    2. Void just before taking the medication.
    3. Wear dark glasses when out in the sun.
    4. Avoid strenuous activity outside when it is hot.
    5. Drink alcohol only in the evening.

    Answer: Keep sugarless hard candy or gum on hand for dry mouth., Void just before taking the medication., Wear dark glasses when out in the sun., Avoid strenuous activity outside when it is hot.

    Anhidrosis can cause heat stroke, voiding before the dose minimizes retention, sugarless candy helps dry mouth, and dark glasses help with photophobia from pupil dilation. Alcohol should be avoided because it can increase the risk of psychosis.

  6. A client taking tolcapone reports dark urine, clay-colored stools and right upper quadrant pain. What is the nurse's priority?

    1. Notify the provider because these may be signs of liver damage.
    2. Increase fluid intake and recheck in a week.
    3. Give the next dose with food.
    4. Tell the client this is a harmless color change in the urine.

    Answer: Notify the provider because these may be signs of liver damage.

    Tolcapone can cause severe, sometimes fatal, hepatocellular injury, and these are listed signs of liver damage to report immediately. Brownish-orange urine alone can be harmless, but with pain and clay-colored stools it points to the liver.

Where every quote comes from

Section 11.2 Anti-Parkinsonian 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.