Parkinson’s disease is believed to be related to an imbalance of dopamine and acetylcholine and a deficiency of dopamine in certain areas of the brain, so drug therapies are aimed at increasing levels of dopamine and/or antagonizing the effects of acetylcholine. Drug therapy does not cure the disease but is used to slow the progression of symptoms. Common medications used to treat Parkinson’s disease are carbidopa/levodopa, selegiline, and amantadine.[1]
Carbidopa/Levodopa
Carbidopa/levodopa is the most common drug used to treat Parkinson’s disease and is usually started as soon as the client becomes functionally impaired.
Mechanism of Action
Administration of dopamine is ineffective in the treatment of Parkinson’s disease because it does not cross the blood-brain barrier, but levodopa, the metabolic precursor of dopamine, does cross the blood-brain barrier and presumably is converted to dopamine in the brain. Carbidopa is combined with levodopa to help stop the breakdown of levodopa before it is able to cross the blood-brain barrier. Additionally, the incidence of levodopa-induced nausea and vomiting is less when it is combined with carbidopa.
Indications for Use
Carbidopa/levodopa is indicated for Parkinson’s disease. It is also used to treat restless leg syndrome.
Nursing Considerations Across the Lifespan
Carbidopa/Levodopa is recommended for use in clients older than age 18. It can take several weeks to see positive effects and this should be explained to clients and their caregivers.
The drug is contraindicated for use with MAOIs. All clients should be observed carefully for the development of depression with concomitant suicidal tendencies.
Clients taking carbidopa and levodopa have reported suddenly falling asleep without prior warning of sleepiness while engaged in activities of daily living (including operation of motor vehicles). Clients should be advised to exercise caution while driving or operating machines during treatment with carbidopa and levodopa.
Sporadic cases of symptoms resembling neuroleptic malignant syndrome (NMS) have been reported in association with dose reductions or withdrawal of certain antiparkinsonian agents. Therefore, clients should be observed carefully when the dosage of levodopa is reduced abruptly or discontinued.
Periodic evaluations of hepatic, hematopoietic, cardiovascular, and renal functions are recommended during extended therapy. The most common adverse effect of carbidopa/levodopa is dyskinesia, which may require dosage reduction.
Clients should be instructed to plan their meal times around medication times to improve their ability to use their utensils and to avoid diets high in protein due to decreased absorption of the medication.
Adverse/Side Effects
Hallucinations and psychotic-like behavior have been reported with dopaminergic medications. Clients taking dopaminergic medications may experience intense gambling urges, increased sexual urges, intense urges to spend money or indulge in binge eating, and/or other intense urges, and the inability to control these urges. These urges stop when the dosage is decreased or the medication is discontinued.
A higher risk for melanoma has been reported. Occasionally, dark red, brown, or black color may appear in saliva, urine, or sweat after ingestion of carbidopa and levodopa. Although the color appears to be clinically insignificant, garments may become discolored.[2],[3],[4]
Client Teaching & Education
Clients should take their medications at regular intervals as directed. If gastric irritation is experienced, clients may eat food shortly after taking medications but high-protein foods may impair drug action. Medications may cause increased drowsiness, dizziness, and orthostatic changes. Clients should carefully assess their skin to monitor for new lesions and any abnormality should be reported to the healthcare provider.
Carbidopa/levodopa Medication Card
Now let’s take a closer look at the medication card for carbidopa-levodopa.[5] Medication cards like this are intended to assist students to learn key points about each medication. Because information about medication is constantly changing, nurses should always consult evidence-based resources to review current recommendations before administering specific medication. Basic information related to each class of medication is outlined below. Prototype or generic medication examples are also hyperlinked to a free resource at Daily Med. On the home page, enter the drug name in the search bar to read more about the medication.
Medication Card 8.11.1: Carbidopa/levodopa
Generic Name: carbidopa/levodopa
Prototype/Brand Name: Sinemet
Mechanism: levodopa is presumably converted to dopamine in the brain. Carbidopa is combined with levodopa to help stop the breakdown of levodopa before it can cross the blood-brain barrier.
Therapeutic Effects
- Reduced progression of symptoms of Parkinson’s disease
Administration
- Avoid high-protein diets
- Monitor hepatic, renal, and hematopoietic functions
- Use in clients over 12
- If gastric irritation, eat food shortly after
Indications
- To treat Parkinson’s and is usually started as soon as the client becomes functionally impaired.
- Also used to treat restless leg syndrome.
Contraindications
- contraindicated for use with MAOIs.
Side Effects
- Depression, suicidal ideation, hallucinations, and intense urges
- Somnolence and fatigue
- NMS symptoms
- Dyskinesia
- Discolored body fluids
- Hypomobility with long-term use
- Higher risk for melanoma
- SAFETY: observe carefully for depression with suicidal ideation.
Nursing Considerations
- Can take several weeks to see effects
- Taper dose when stopping
- Plan mealtimes around med times
- monitor for new lesions
- Monitor for sudden somnolence and depression
Selegiline
Selegiline is often used in conjunction with carbidopa-levodopa when clients demonstrate a deteriorating response to this treatment. It is helpful to control symptom fluctuations.[6]
Mechanism of Action
Selegiline inhibits MAO-B, blocking the breakdown of dopamine.[7]
Indications for Use
Selegiline capsules are indicated as an adjunct in the management of Parkinsonian clients being treated with levodopa/carbidopa who exhibit deterioration in the quality of their response to this therapy. There is no evidence from controlled studies that selegiline has any beneficial effect in the absence of concurrent levodopa therapy.
Nursing Considerations Across the Lifespan
Large doses of selegiline may inhibit MAO-A that promotes the metabolism of tyramine in the GI tract, which can cause a hypertensive crisis.
Adverse/Side Effects
Side effects are dose-dependent, with larger doses posing a hypertensive crisis risk in conjunction with the consumption of food or beverages with tyramine. Higher doses can increase the risk for hypertensive crises.
Client Teaching & Education
Clients should be advised to avoid foods high in tyramine. Additionally, medications may cause increased drowsiness, dizziness, and orthostatic changes. If clients experience abnormal behaviors such as hallucination, sexual urges, gambling, etc., this should be reported promptly to the healthcare provider.
Selegiline Medication Card
Now let’s take a closer look at the medication card for selegiline.[8]
Medication Card 8.11.2: Selegiline
Generic Name: selegiline
Prototype/Brand Name: Eldepryl
Mechanism: Selegiline inhibits MAO-B, blocking the breakdown of dopamine.
Therapeutic Effects
- Reduction in progression of Parkinson’s disease symptoms
Administration
- Avoid foods with tyramine
Indications
- Used in conjunction with carbidopa-levodopa when clients demonstrate a deteriorating response to this treatment.
Contraindications
- tyramine
Side Effects
- Side effects are dose-dependent, with larger doses posing a hypertensive crisis risk if there is consumption of food or beverages with tyramine.
Nursing Considerations
- may cause increased drowsiness, dizziness, and orthostatic changes.
- Report any abnormal behaviours to HCP
Amantadine
Amantadine is used in the early stages of Parkinson’s disease but can be effective in moderate or advanced stages in reducing tremor and muscle rigidity.[9]
Mechanism of Action
The exact mechanism of action is unknown. Amantadine is an antiviral drug that acts on dopamine receptors.[10]
Indications for Use
Amantadine is used for Parkinson’s disease, medication-induced extrapyramidal symptoms, and influenza A.
Nursing Considerations Across the Lifespan
Use cautiously with renal impairment. This drug may cause suicidal ideation and should not be stopped abruptly or can cause Parkinsonian crisis. Neuroleptic Malignant Syndrome (NMS) has been reported in association with dose reduction or withdrawal of amantadine therapy.
Adverse/Side Effects
Suicide ideation, congestive heart failure, and peripheral edema can occur. This drug can cause intense gambling urges, increased sexual urges, intense urges to spend money uncontrollably, and other intense urges with an inability to control them. There is an increased risk of melanoma.
Adverse reactions reported most frequently are nausea, dizziness (lightheadedness), and insomnia. This drug can also cause anticholinergic side effects, impaired thinking, and orthostatic hypotension.[11]
Client Teaching & Education
Clients should take medications as directed and ensure they do not skip or double doses. Medications may cause drowsiness, dizziness, and orthostatic blood pressure changes. Clients should avoid using this medication with OTC cold medications or alcoholic beverages. If clients, family, or caregivers note worsening depression or suicidality, this should be reported immediately to the healthcare provider.
Amantadine Medication Card
Now let’s take a closer look at the medication card for amantadine.[12] Because information about medication is constantly changing, nurses should always consult evidence-based resources to review current recommendations before administering specific medication.
Medication Card 8.11.3: Amantadine
Generic Name: amantadine
Prototype/Brand Name: Symmetrel
Mechanism: Exact mechanism unknown. Antiviral drug that acts on dopamine receptors
Therapeutic Effects
- Reduction in progression of Parkinson’s disease symptoms
Administration
- Monitor renal function
- Monitor mental state
- Assess blood pressure
Indications
- Used in the early stages of Parkinson’s disease but can be effective in moderate or advanced stages in reducing tremor and muscle rigidity.
Contraindications
- Known hypersensitivity
Side Effects
- Increased suicidality and urges
- CHF and peripheral edema
- Neuromalignant syndrome (NMS)
- Orthostatic hypotension
- Nausea, dizziness, and insomnia
- Anticholinergic side effects
Nursing Considerations
- Taper dose carefully
- Monitor BP
- Monitor for suicidal thoughts or behavior, and/or any unusual changes in mood or behavior
Clinical Reasoning and Decision-Making Activity 8.11
A 76-year-old client in a long-term care center has developed a shuffling gait with a stooped posture, along with a hand tremor at rest. The nurse practitioner prescribed carbidopa/levodopa.
1. The nurse knows that Parkinson’s disease is related to dopamine, but dopamine can’t cross the blood-brain barrier. How will carbidopa/levodopa assist with dopamine levels?
2. The client states, “I am looking forward to spending next weekend with my grandson. He even said he would let me drive his new Mustang!” What teaching should the nurse provide the client and his grandson (with the client’s permission) regarding the new medication and his weekend plans?
3. The nurse reads that the most common side effect of carbidopa-levodopa is dyskinesia. What is dyskinesia? If it occurs, what is the likely treatment?
Note: Answers to the Critical Thinking activities can be found in the “Answer Key” sections at the end of the book.
- Lilley, L., Collins, S., & Snyder, J. (2020). Pharmacology and the Nursing Process. pp. 246-272. Elsevier. ↵
- This work is a derivative of Daily Med by U.S. National Library of Medicine in the public domain. ↵
- McCuistion, L., Vuljoin-DiMaggio, K., Winton, M, & Yeager, J. (2018). Pharmacology: A patient-centered nursing process approach. pp. 227-305. Elsevier. ↵
- Lilley, L., Collins, S., & Snyder, J. (2020). Pharmacology and the Nursing Process. pp. 246-272. Elsevier. ↵
- This work is a derivative of Daily Med by U.S. National Library of Medicine in the public domain. ↵
- Lilley, L., Collins, S., & Snyder, J. (2020). Pharmacology and the Nursing Process. pp. 246-272. Elsevier. ↵
- This work is a derivative of Daily Med by U.S. National Library of Medicine in the public domain. ↵
- This work is a derivative of Daily Med by U.S. National Library of Medicine in the public domain. ↵
- Lilley, L., Collins, S., & Snyder, J. (2020). Pharmacology and the Nursing Process. pp. 246-272. Elsevier. ↵
- McCuistion, L., Vuljoin-DiMaggio, K., Winton, M, & Yeager, J. (2018). Pharmacology: A patient-centered nursing process approach. pp. 227-305. Elsevier. ↵
- This work is a derivative of Daily Med by U.S. National Library of Medicine in the public domain. ↵
- This work is a derivative of Daily Med by U.S. National Library of Medicine in the public domain. ↵
A nearly impenetrable barricade that is built from a tightly woven mesh of capillaries cemented together to protect the brain from potentially dangerous substances such as poisons or viruses.