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.