Chapter 15: Antiparkinson Drugs Flashcards
Explain the action of Carbidopa-Levodopa medication (Sinemet).
Carbidopa prevents Levodopa from breaking down, allowing it to cross into the blood brain barrier.
Through which route is carbidopa-levodopa excreted?
Urine
Dopaminergics
Affect dopamine content of the brain.
Dizziness may occur when starting this therapy.
May give with food to prevent GI upset.
Dopamine Agonists
Stimulate dopamine receptors of nerve cells in the brain.
Anticholinergic therapy for Parkinson’s
Inhibit activity of Acetylcholine.
Treats muscle tremors and rigidity due to excessive cholinergic activity.
MAO - B inhibitors
Break down catecholamines in the CNS primarily in the brain.
Ex: Selegilline & Rasagilline
explain the action of Rivastigmine
Increases availability of acetylcholine in the neuron receptors. Helps treat mild to moderate dementia and Parkinson’s.
Which route of administration for rivastigmine results in a peak concentration between 8 and 16 hours?
Transdermal
Pre-Med Assessment for Carbidopa-Levodopa
- Determine Baseline Data:
-Vital signs
-Laboratory tests: Complete blood count (CBC), liver function test (LFT), prolactin level, pregnancy test
-Symptoms: Current motor symptoms and any impairment to ADLs - Identify High-Risk Patients
-Review the patient’s medical history for contraindications or conditions in which this drug should be used with caution.
-Review the patient’s medication history; report possible interactions.
Contraindications and Interactions with Carbidopa-Levodopa
- Contraindications: Glaucoma, malignant melanoma
- Cautions: History of myocardial infarction (MI), dysrhythmias, asthma, emphysema, renal/hepatic impairment, pulmonary impairment, seizure disorder, peptic ulcer disease, depression
- Interactions
Drug :When certain drugs are used concurrently with levodopa the following may occur:
Anticholinergics and antipsychotics may reduce the effect of levodopa.
Tricyclic antidepressants (TCAs) may cause dyskinesia and hypertension.
Methyldopa may cause psychosis.
MAO inhibitors can result in severe hypertension.
MAO inhibitors may trigger melanoma; monitor skin for changes.
Patients with heart disease or mental disorders or those on MAO-B inhibitor therapy should use with caution.
Foods high in protein may reduce levodopa absorption from the intestine.
Laboratory Tests
Blood urea nitrogen (BUN), aspartate aminotransferase (AST), alanine aminotransferase (ALT), alkaline phosphatase (ALP), and lactate dehydrogenase (LDH) levels could show an increase.
Previous
Dosage and Administration of Carbidopa-Levodopa
Immediate Release PO: three to four times a day
No more than eight tablets or 80 mg carbidopa/800 mg levodopa (80/800 mg) per day
Initial dose: One tablet of 10 or 25 mg carbidopa/100 mg levodopa
Maintenance: 25/250 mg
Extended-Release Capsules PO: two times a day
No more than 1600 mg/day
Initial dose: 50 mg carbidopa/200 mg levodopa
Enteral Suspension 2000 mg/day over 16 hours
Side Effects and Adverse Effects of Carbidopa-Levodopa
Intervention for Carbidopa-Levodopa
- Monitor for orthostatic hypotension with initial doses; symptoms include dizziness and fainting upon changing positions.
- Give with foods that are low in protein, because a high-protein diet may inhibit transport of levodopa to the CNS.
- Screen for signs or symptoms relative to parkinsonism, including stooped forward posture, shuffling gait, masked facies, and resting tremors.
Evaluation for Carbidopa-Levodopa
-Assess for reductions in tremor and rigidity.
-Assess for improvement in balance, gait, and mobility.
-Assess for side effects.
Pre-Med Assessment for Rivastigmine
- Medical history, noting renal or liver disease, peptic ulcer, chronic obstructive pulmonary disease (COPD), asthma, or urinary obstruction
- History of behavioral changes
- Family coping ability
Symptoms
- Mental and physical abilities; any impairments in self-care or cognition
- Behavioral disturbances
- Aphasia
- Motor function
Contraindications and Interactions with Rivastigmine
- Contraindications:
History of reactions to rivastigmine at application site; hypersensitivity to drugs with similar compounds (carbamate derivatives) - Cautions:
Liver/renal disease
Simultaneous nonsteroidal antiinflammatory drug (NSAID) use
Peptic ulcers
Urinary obstruction
Sick sinus syndrome, bradycardia, or supraventricular defects
COPD, asthma
Patients under 50 kg (110 lb)
Seizure disorders
Urinary retention - Interaction:
- Effects of theophylline and general anesthetics are increased.
-TCAs decrease effects of rivastigmine.
-Cimetidine increases effects of rivastigmine.
-NSAIDs increase GI effects.
-Tobacco increases rivastigmine clearance.
-Herb: Cholinergic effects may be increased with gingko biloba.
Laboratory Tests: May result in higher levels of ALT and AST
Dosage and Administration of Rivastigmine
can be given orally or transdermal
Side Effects and Adverse Effects of Rivastigmine
Intervention for Rivastigmine
Provide consistent care.
Provide ambulation assistance.
Assess for side effects common to prolonged use of AChE inhibitors.
Check vital signs often for bradycardia or hypotension.
Note any changes in behavior, whether better or worse.
Evaluation for Rivastigmine
Look for any medical or physical improvements, which prove the effectiveness of the current drug therapy.
Which baseline laboratory tests would be obtained for a female patient who has been prescribed carbidopa-levodopa?
Complete blood count (CBC)
Blood dyscrasias can occur when taking carbidopa-levodopa, including thrombocytopenia, hemolytic anemia, and agranulocytosis. A baseline evaluation of the CBC is necessary to ensure adequate levels of red blood cells, white blood cells, and platelets and will aid in identification of blood dyscrasias that may be caused by carbidopa-levodopa after treatment is initiated.
Liver function tests (LFTs)
These medications are metabolized by the liver. If liver dysfunction is present, the dosage of the medications may need to be reduced to decrease the risk for medication toxicity.
Prolactin level
Levodopa can suppress prolactin production. A baseline level is warranted in the event symptoms of low prolactin develop after initiation of levodopa/carbidopa therapy.
Pregnancy test
Levodopa may have a risk for teratogenicity and should be avoided during pregnancy.
Which adverse effect of carbidopa-levodopa would the nurse teach the patient and family to report to the health care provider?
Dyskinesia (involuntary muscle movement) may occur with high levodopa dosages and should be reported. The health care provider may need to alter the medication dosage.
Which instructions would the nurse include in patient teaching for a patient taking extended-release carbidopa-levodopa?
Do not abruptly stop taking this medication
You may continue to have symptoms for several weeks or months .
You may experience discolored urine or dark perspiration while taking this medication.
A nurse administers oral carbidopa-levodopa to a patient who has tremors caused by Parkinson’s disease. The nurse would expect to see the medication effect in which time frame?
5 hours
what is the therapeutic effect of rivastigmine?
improves memory
Rivastigmine must be used with caution in patients with which condition?
asthma
Which foods would the nurse instruct a patient who is taking selegiline to avoid?
aged cheese, wine and banana
Which instruction is most important for the nurse to include when teaching a patient who has been prescribed sustained-released carbidopa-levodopa?
“Watch for adverse effects like dizziness and drowsiness.”
Which effect may occur when theophylline and rivastigmine are administered together?
Increased risk for theophylline toxicity
To evaluate the effectiveness of dopaminergic agents, the nurse would assess for which condition?
improvement in balance
The therapeutic goal for treatment of Parkinson’s disease is
Improve the patient’s ability to carry out activities of daily living
Which statement about carbidopa-levodopa is accurate?
Carbidopa-levodopa should not be stopped abruptly.
Which statement about the mechanism of action of carbidopa is accurate?
carbidopa has no therapeutic effect on its own.
A nurse administers oral carbidopa-levodopa to a patient who has tremors caused by Parkinson’s disease. The nurse would expect to see the medication effect in which time frame?
5 hours
Which statement is accurate about the pharmacodynamics of topical rivastigmine?
Onset of action is 0.5 to 1 hour.
which description of the therapeutic effect of rivastigmine is accurate?
Improves memory
Rivastigmine must be used with caution in patients with which condition?
Asthma
The nurse is preparing to administer rivastigmine to a patient. The prescription states to administer 8 mg b.i.d. The pharmacy sends four 2-mg tablets for the morning dose. Which action would the nurse take?
Call the health care provider for a prescription change.
Which factor in a patient’s health history is most important for the nurse to consider with regard to treatment for Alzheimer’s disease using rivastigmine?
Liver disease
A family member states, “My father complains of an upset stomach after taking rivastigmine.” Which response by the nurse is appropriate?
“Make sure he takes the medication with food.”
Selegiline & Rasagiline
(MOAIs)
MOA inhibitors.
They increase dopaminergic stimulation in CNS.
MAOI interactions with Tyramine
MAOI when taken with Tyramine rich foods, prevents breakdown of Tyramine which causes high levels of Tyramine in the blood (causing high level of BP).
MAOI interactions with Tyramine
MAOI when taken with Tyramine rich foods, prevents breakdown of Tyramine which causes high levels of Tyramine in the blood (causing high level of BP).
Dyskinesia
Difficulty performing voluntary movements.
Levodopa Therapy
Levodopa is converted to dopamine, and released when needed.
As a result, neurotransmitter imbalance is controlled
Adverse effects of Levodopa therapy
Confusion, involuntary movements, GI distress, hypotension, cardiac dysrhythmias
Sinemet
Carbdidopa-levodopa combination helps treat Parkinson’s.
Take on empty stomach.
For GI upset, can take with food.
Anticholinergic Therapy side effects:
Dry mouth, decreased saliva, urinary retention, constipation, dilated pupils, muscle relaxation
Benztropine (cogentin)
Anticholinergic used for Parkinson’s.
May cause hyperthermia, caution in hot weather. Tachycardia.
Hypertensive crisis may result from taking these two drugs.
Levodopa and MAOIs.
A dangerous drug interaction may occur if taken together.
MAOIs are meds used for early Parkinson’s.
Levodopa is considered most effective for treatment for motor symptoms in Parkinson’s
Which Parkin’s medication can darken urine and sweat?
Entacapone.
This medication is used in combination with levodopa/carbidopa
