Pharmacology Ch. 21-22 (Test 2)

Adverse Effects: pramipexole

(Used alone) - nausea, dizziness, daytime somnolence (severe narcolespy), insomnia, constipation weakness, and hallucinations (Combined with levadopa)- orthostatic hypotension and dyskinesias and increase in hallucinations Rare instances of pathologic gambling and other compulsive self-rewarding behaviors

Dopaminergic agents (name a drug)

*(mimics dopamine)* By far the most commonly used drugs for PD Promote activation of dopamine receptors *levodopa*

Anticholinergic agents (drug)

*(slows aCh)* Prevent activation of cholinergic receptors (blocks aCh) *benztropine*

Cardinal Symptoms of PD

*Dyskinesias (difficulty with movement)* Tremor at rest, improves with purposeful movement Rigidity Instable posture Bradykinesia (slowed movement) Excessive sweating, Orthostatic hypotension, Gastric retention, Urinary retention,

What are Dopamine Agonists

*First-line drugs for PD *Direct activation of dopamine receptors in the brain *Less effective than levodopa *Don't have to be activated *Two types

levodopa

*Only given in combination with carbidopa* -highly effective, but benefits -deteriorate over time -may take months to become fully effective -food decreases absorption -high-protein foods will reduce therapeutic effects

Anticholinergic Drugs (drug)

*benztropine* Second-line therapy to help with treatment Have anticholinergic side effects like dry mouth, constipation, urinary retention

carbidopa

-No adverse effects of its own -Increases available levodopa in the CNS and allows for 75% decrease in levodopa dosage; therefore, reduces cardiovascular and GI adverse effects -Keeps levodopa from being fully deactivated by enyzmes before it gets to the brain

pramipexole

-Used alone in early PD -Takes several weeks to fully work

Therapeutic Goals Parkinson's Disease

-improve patient's ability to carry out activities of daily life *(ADLs)* -Drug dosages are determined by extent to which PD interferes with activities of daily living

Major Risk Factors of AD

Advancing age Family history

drug "holidays" recommended

Drug holidays involve stopping the drug for a period of time, ex. 1 week off, Dopamine agonist should be taken to prevent serious reactions from sudden withdrawal.

The nurse cares for a patient receiving pramipexole (Mirapex). The nurse is most concerned if the patient makes which statement? A. "I now use a patch instead of taking birth control pills." B. "Sometimes I just fall asleep without warning." C. "The pills make me sleepy, so I take a nap in the afternoon." D. "I have noticed that this medicine makes me constipated."

B. "Sometimes I just fall asleep without warning."

A patient taking levodopa/carbidopa (Sinemet) for Parkinson's disease experiences frequent "on-off" episodes (or abrupt loss of effect). Which action by the nurse is best? A. Administer the medication on an empty stomach. B. Instruct the patient to avoid high-protein foods. C. Have the patient increase intake of vitamin B6. D. Discontinue the drug for 10 days (for a "drug holiday").

B. Instruct the patient to avoid high-protein foods.

An elderly patient with skin cancer and hypertension is prescribed levodopa/carbidopa (Sinemet) to treat Parkinson's disease. Which action by the nurse is best? A. Give the medication if the blood pressure is normal. B. Administer the medication as prescribed. C. Ask the patient about the type of skin cancer. D. Hold the medication if the patient is older than 65 years.

C. Ask the patient about the type of skin cancer.

Causes of AD in the brain

Cerebral atrophy (brain wasting) Tangled neurofibers in neurons Plaques (dead areas)

Adverse effects: Cholinesterase inhibitors

Cholinergic side effects (parasympathetic) Increased GI acid secretion Dizziness Headache Bronchoconstriction Bradycardia* rare but dangerous, may need a pacemaker

donepezil

Cholinesterase (those that slow aCh) inhibitors

What can reduce responses to cholinesterase inhibitors

Drugs that block cholingenic receptors (first-generation antihistamines) some antidepressants & antipsychotics

A patient with mild symptoms of Alzheimer's disease is prescribed donepezil (Aricept). Which statement made by the patient indicates a need for further teaching? A. "The drug will improve transmission by neurons in my brain." B. "I may experience an upset stomach while taking this drug." C. "I will take the drug every night at bedtime with a snack." D. "The drug will stop damage to the neurons in my brain

D. "The drug will stop damage to the neurons in my brain

A patient is prescribed a dopamine agonist, pramipexole (Mirapex). Which statement made by the patient indicates a need for further teaching? A. "The drug should be taken with food to prevent nausea." B. "I may experience hallucinations while taking this drug." C. "I should rise slowly to prevent dizziness and fainting." D. "This drug will stop the progression of Parkinson's disease."

D. "This drug will stop the progression of Parkinson's disease."

Nonmotor Symptoms and Their Management (PD) (drug)

Depression -*amitriptyline* (only effective drug) confusion/ hypertension -May also take a CNS stimulant to reduce daytime sleepiness -May also have dementia similar to Alzheimer's disease and will be treated similarly.

What are the two types of Dopamine Agonists?

Derivatives of ergot Nonergot derivatives

What is Alzheimer's Disease

Devastating illness, *irreversible* Progressive memory loss Impaired thinking Hallucinations, delusions Inability to perform routine tasks of daily living

Adverse effects: memantine

Dizziness Headache Confusion Constipation

pramipexole. entacapone. amantadine. selegiline. are all examples of

Dopamine agonists

Two major categories of drug therapy for Parkinson's Disease

Dopaminergic agents Anticholinergic agents

memantine

First drug in a new class, the NMDA receptor antagonists Indicated for moderate to severe AD Better tolerated than cholinesterase inhibitors

levodopa/carbidopa/entacapone

Fixed-dose combinations sold as *Stalevo* More convenient than taking separate doses Costs a little less Disadvantage: (Available only in immediate-release tablets)

COMT Inhibitors (drug)

Inhibit metabolism of levodopa in the periphery (outside of the brain) No direct therapeutic effects of their own *entacapone*

What should you take for mild symptoms of PD

MAO-B inhibitor (more effective than dopamine agonists, but long-term use carries a higher risk for disabling dyskinesias)

Adverse effects: selegiline

Monotherapy: insomnia Drug interactions: levodopa (can worsen levodopa adverse reactions, Can cause hypertensive crisis if taken with high tyramine foods (aged food)

Adverse effects: levodopa

Nausea and vomiting Dyskinesias (difficulty moving, abnormal movements, tics, grimacing), amantadine (dopamine agonist) may help Cardiovascular effects - orthostatic hypotension, dysrhythmias Psychosis May darken sweat and urine Can activate malignant melanoma (most dangerous skin cancer)

memantine is a

Neuronal receptor blocker

______cure for motor symptoms

No Drug therapy can maintain functional mobility for years (prolongs/improves quality of life)

Pathophysiology of AD

Reduced cholinergic transmission due to damaged neurons *Levels of acetylcholine to low* Degeneration of neurons (hippocampus---cerebral cortex)

entacapone

Selective, reversible inhibitor of COMT Only for use with levodopa Inhibits metabolism of levodopa in the intestines and peripheral tissues Prolongs time that levodopa is available to the brain

How do symptoms of (AD) Progressive

Symptoms typically begin after age 65 years, but may appear as early as age 40 years. Life expectancy from symptom onset may be 20 years or longer, but is usually 4 to 8 years.

selegiline

used alone) or used with levodopa Modest improvement in motor function Causes selective inhibition of type B monoamine oxidase (MAO-B) Can *suppress destruction of dopamine derived from levodopa and prolong the effects of levodopa*

Symptoms of AD

Memory loss Confusion Feeling disoriented Impaired judgment Personality changes Difficulty with self-care Wandering, pacing, agitation, screaming, inability to recognize family and communicate

Parkinson's Disease

Parkinson's disease (PD) is a degenerative neurologic disorder effecting the brain. There is *not enough dopamine* to allow for balance in the brain.

Imbalance results from

*degeneration of the neurons that supply dopamine* to the brain. Without adequate dopamine, ACh causes excessive stimulation of the brain *Loss of ability to control movement *

donepezil

Cholinesterase inhibitors Indicated for mild to moderate AD *Prevent breakdown of acetylcholine* May help to slow progression of disease

MAO-B Inhibitors (can reduce what?)

Considered first-line drugs for treatment of PD Combination with levodopa - can reduce the wearing-off effect *selegiline* is an example

What do COMT or MAO inhibitors do

enhance effects of levodopa by blocking its degradation

What should you take for severe symptoms of PD

levodopa or a dopamine agonist

Symptoms of PD generally appear in

middle age and progresscure for motor symptoms

Name a Nonergot Dopamine Agonists

pramipexole

3 Drug interactions: levodopa (good or bad)

some antipsychotics (block levadopa), MAOIs (can cause severe HTN), anticholinergics (help levadopa)

Cholinesterase inhibitors may delay or slow progression of disease, but will not

stop it.

"Off" times

times of reduced drug effectiveness

Mechanisms of action: levodopa Dopamine agonists

- promotes dopamine synthesis (turns into dopamine) -attach to dopamine receptors directly and mimic -enhance effects of levodopa by blocking its degradation

Things to monitor in PD patients

Changes throughout therapy Monitor weight for weight loss Dysphagia (difficulty swallowing) Treat constipation (increase fiber and fluid intake) Monitor and protect from injury May have loss of therapeutic effect (drug holiday needed?) Take as prescribed Treat dry mouth (sugar-free gum, sips of water) Treat fall and injury risk (stiff position changes, bed alarm, only get up with assistance)

A patient is concerned about developing Alzheimer's disease (AD). What should the nurse include in the teaching plan? A. Estrogen replacement therapy improves cognitive functioning. B. No solid evidence supports the use of drugs to prevent AD. C. Naproxen taken daily after age 50 years decreases the risk of AD. D. Daily doses of gingko biloba can prevent cognitive decline.

B. No solid evidence supports the use of drugs to prevent AD.

What do Dopamine agonists do

attach to dopamine receptors directly and mimic

What drug is levodopa normally given with

carbidopa

Drug therapy cannot

correct or reverse symptoms. will hopefully *slow the progression* of the disease