CNS Medications and Neurotransmitters

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Questions and Answers

What is a primary adverse effect associated with pramipexole when used alone?

Severe headache

Tachycardia

Hypertension

Nausea (correct)

Which of the following statements about pramipexole is accurate?

It can produce hallucinations when used with levodopa/carbidopa. (correct)

It is ineffective in the early stages of Parkinson's disease.

It should be taken only on an empty stomach.

It eliminates the need for other medications.

Which of the following is NOT a nursing consideration for patients taking pramipexole?

Increase intake of protein-rich meals. (correct)

Avoid rising quickly from a sitting position.

Report any new tremors or twitching.

Monitor for signs of racing heart or palpitations.

Which mechanism describes how antiepileptic drugs (AEDs) work by suppressing the transmission of neurotransmitters?

Inhibition of sodium channels Signup and view all the answers

Which statement is true regarding impulse control disorders in relation to pramipexole?

They are a common concern with pramipexole treatment. Signup and view all the answers

What is a serious adverse effect associated with oxcarbazepine?

Hyponatremia Signup and view all the answers

Which of the following statements about barbiturates is true?

They are considered serious teratogens. Signup and view all the answers

What is the primary goal of treating an epileptic status?

To intervene within the first 5 minutes. Signup and view all the answers

Which of the following drugs is known to produce serious skin reactions?

Oxcarbazepine Signup and view all the answers

What characterizes the pathophysiology of Alzheimer's Disease?

Very low levels of acetylcholine Signup and view all the answers

What is the main effect of dopaminergic agents in the treatment of Parkinson's Disease?

Activate dopamine receptors directly or indirectly Signup and view all the answers

Which of the following statements about Levodopa is true?

It requires conversion to an active form after crossing the blood-brain barrier. Signup and view all the answers

What role does carbidopa play when combined with Levodopa?

It prevents the decarboxylation of Levodopa. Signup and view all the answers

What is a common adverse effect of Levodopa?

Psychosis, including hallucinations Signup and view all the answers

What percentage of Levodopa actually reaches the brain effectively?

2% Signup and view all the answers

When is it recommended to take Levodopa to avoid gastrointestinal upset?

Without food Signup and view all the answers

Which medication is specifically used to block the effects of acetylcholine?

Anticholinergic agents Signup and view all the answers

What is ‘Loss of Effect’ in relation to Levodopa?

A gradual decrease in the drug's effectiveness over time. Signup and view all the answers

What is a characteristic finding in spasticity?

Decreased dexterity Signup and view all the answers

Which medication is primarily used for the treatment of muscle spasm?

Cyclobenzaprine Signup and view all the answers

What is a common adverse effect associated with Cyclobenzaprine?

Dry mouth Signup and view all the answers

Which condition is NOT a cause of muscle spasms?

Multiple sclerosis Signup and view all the answers

What is the main adverse effect of Dantrolene?

Hepatotoxicity Signup and view all the answers

Which drug acts specifically within the spinal cord to manage spasticity?

Baclofen Signup and view all the answers

What interaction should be strictly avoided when using Cyclobenzaprine?

Alcohol Signup and view all the answers

Which treatment option is NOT typically part of managing muscle spasms?

Corticosteroids Signup and view all the answers

What is the primary goal of potentiating GABA in the context of epilepsy treatment?

To decrease focal epileptic activity and prevent its spread Signup and view all the answers

Which of the following is a traditional antiepileptic drug that acts as a sodium channel suppressor?

Phenytoin Signup and view all the answers

What is a notable side effect of Phenytoin that patients may experience?

Gingival hyperplasia Signup and view all the answers

Which of the following statements accurately describes a difference between traditional and newer antiepileptic drugs?

Newer drugs tend to have fewer adverse effects compared to traditional ones Signup and view all the answers

What factor contributes to Phenytoin being a narrow therapeutic index (NTI) drug?

The liver easily becomes overwhelmed, leading to toxic levels Signup and view all the answers

Which of the following medications can also be used to treat bipolar disorder and migraines?

Valproic Acid Signup and view all the answers

What role does Phenobarbital play in epilepsy treatment?

It potentiates the effects of GABA Signup and view all the answers

What is a common characteristic of the metabolism of Phenytoin?

It has a half-life that is dose dependent Signup and view all the answers

What is the primary mechanism of action of cholinesterase inhibitors such as Donepezil?

Prevents breakdown of acetylcholine Signup and view all the answers

Which of the following side effects is associated with increased acetylcholine levels due to cholinesterase inhibitors?

Salivation Signup and view all the answers

What is a significant characteristic of the cholinesterase inhibitor Rivastigmine?

Administered via a transdermal patch Signup and view all the answers

What is the primary benefit of using Memantine in Alzheimer's treatment?

Slows the decline of cognitive function Signup and view all the answers

What is the main adverse effect of cholinesterase inhibitors that is related to the gastrointestinal system?

Dyspepsia Signup and view all the answers

What does the combination of donepezil and memantine provide?

A potentiated effect Signup and view all the answers

What is the effect of cholinesterase inhibitors on disease progression in Alzheimer's patients?

Does not delay disease progression Signup and view all the answers

Which of the following correctly describes NMDA antagonists' mechanism of action?

Block NMDA receptors to prevent excessive calcium accumulation Signup and view all the answers

Study Notes

Central Nervous System Medications

Medications for the central nervous system (CNS) target various conditions.
Chapters 12 and 14 cover these medications.

The Nervous System

The nervous system is a complex network.
It's divided into central and peripheral systems.
The central nervous system includes the brain and spinal cord.
The peripheral nervous system comprises cranial and spinal nerves, plus parts of the autonomic system.
The autonomic system controls involuntary functions like heart rate and digestion
- Divided into sympathetic ("fight or flight") and parasympathetic ("rest and digest") divisions.
The somatic nervous system controls voluntary movements.

CNS Neurotransmitters

Acetylcholine is involved in memory and learning.
Dopamine regulates mood and motor control ("joy").
Glutamate is essential for memory.
GABA plays a role in memory and movement.

Parkinson's Disease Treatments

Parkinson's disease is caused by insufficient dopamine and excessive acetylcholine.
Treatments aim to restore balance.
Dopaminergic agents directly or indirectly increase dopamine.
Anticholinergic agents block acetylcholine receptors.

Levodopa: Dopamine Replacement

Levodopa is a precursor to dopamine, increasing dopamine levels.
It's a prodrug; converted to active form after crossing the blood-brain barrier (BBB).
Only about 2% of levodopa reaches the brain.
Food, especially high-protein meals, slows absorption.
Short half-life (1-2 hours).
"Loss of effect" is a common problem.

Carbidopa/Levodopa (Sinemet)

Carbidopa prevents levodopa breakdown before reaching the brain.
This allows for a lower levodopa dose.
Available only as a combined pill.

Levodopa Adverse Effects

Nausea and vomiting (N/V) are common side effects.
Dyskinesia (involuntary movements) can occur.
Cardiovascular issues (e.g., low blood pressure) may happen.
Psychosis (hallucinations, delusions) is possible.
Urine and sweat may darken.
Interactions with other medications that block dopamine receptors are possible.
Certain medications can enhance the effect of levodopa, causing side effects.

Nursing Considerations for Levodopa

Advise patients to take medication without food unless advised otherwise.
Inform patients about the possible darkening of urine and sweat.
Encourage patients to report "loss of effect".
Encourage patients to rise slowly from a lying or sitting position.
Monitor patients for new tremors or twitching.
Instruct patients to report any changes in heart rate, palpitations or other relevant symptoms.
Educate patients about potential hallucinations or paranoia.

Pramipexole: Dopamine Receptor Agonist

Pramipexole directly activates dopamine receptors in the brain.
Often used as a first-line treatment.
Can be used alone in early stages of Parkinson's disease, or with levodopa/carbidopa in advanced stages.

Pramipexole Adverse Effects

Common side effects include nausea, dizziness, and sleep disturbances.
Less common but serious side effects include orthostatic hypotension, dyskinesias, hallucinations, and sleep attacks.
Impulse control disorders may occur.

Nursing Considerations for Pramipexole

Advise patients to take the medication with food.
Educate patients about the importance of rising slowly from supine or sitting positions.
Instruct patients to report sleep disturbances, especially sleep attacks.
Counsel patients about potential impulse control concerns.

Drugs for Seizures (AEDs)

Antiepileptic drugs (AEDs) target neuronal activity.
AEDs work by:
- Reducing sodium influx in cell membranes.
- Blocking calcium channels in axon terminals.
- Antagonizing glutamate.
- Potentiating GABA.

Traditional and Newer Antiepileptic Drugs (AEDs)

Phenytoin and Phenobarbital are traditional AEDs.
Oxcarbazepine and others are newer types.
Newer AEDs are often more expensive.
Traditional AEDs have more interactions and side effects.

Phenytoin (AED Prototype)

Phenytoin is a sodium channel blocker.
Often used as a first-line treatment.
Therapeutic levels 10-20 mcg/mL.
Primarily affects neurons, reducing electrical activity in the brain.
Liver sensitivity is high.
Half-life varies significantly based on dosage.
Induces certain liver enzymes.

Phenytoin Adverse Effects

Possible effects include headache, drowsiness, irritability.
Higher levels lead to cognitive impairment, nystagmus, ataxia, and diplopia.
Can contribute to gingival hyperplasia and rashes.
Teratogenic, meaning it can cause birth defects in infants born to mothers on the medication.
Many interactions with other medications.

Other Traditional AEDs (Valproic Acid & Phenobarbital)

Valproic Acid is a widely used medication effective across seizure types and other conditions.
It affects sodium, calcium channels and potentiates GABA.
Valporic Acid is known to cause serious birth defects.
Phenobarbital potentiates GABA neurotransmitter activity.
It's used for major seizure types, bipolar disorder, certain migraines.
Sedation is a prominent adverse effect of phenobarbital.

Oxcarbazepine (Newer AED Prototype)

Oxcarbazepine is a sodium channel blocker.
No routine drug level monitoring.
Adverse CNS effects include dizziness, drowsiness, double vision, nystagmus, headache, and ataxia.

• Other adverse effects include hyponatremia, and rare, serious skin reactions.

Status Epilepticus

Status epilepticus is a prolonged seizure activity.
It's a medical emergency!
Goals are to restore airway, give IV benzodiazepine then AEDs, as soon as possible.

Drugs for Alzheimer's Disease

Alzheimer's disease has an unknown pathophysiology.
Acetylcholine levels are reduced.
Cholinesterase inhibitors and NMDA antagonists are the main classes of drugs to treat the condition.

Donepezil (Cholinesterase Inhibitor)

Donepezil prevents acetylcholine breakdown.
Benefits include improved quality of life, memory, and reasoning.
Does not delay disease progression.
High protein binding leads to a long half-life.
Available as an oral disintegrating tablet (ODT).
Cholinergic side effects possible (SLUDGE)

Rivastigmine (Cholinesterase Inhibitor)

Rivastigmine also inhibits acetylcholine breakdown, improving quality of life.
Available as a transdermal patch.

Memantine (NMDA Antagonist)

Memantine blocks NMDA receptors and prevents excess calcium buildup.
Helps slow cognitive decline, and may improve symptoms without modifying the underlying disease progression.
Few adverse effects.
Can be used in conjunction with donepezil.

Drugs for Muscle Spasm and Spasticity

Spasm is an involuntary muscle contraction.
Spasticity is prolonged muscle tightness.
Underlying causes include various conditions, like injuries and chronic pain syndromes.
Several medications and physical therapies can manage these issues.

Cyclobenzaprine

Centrally acting muscle relaxer typically for relieving muscle spasms.
Relatively few adverse effects.
Can cause central nervous system (CNS) side effects, like drowsiness and dizziness.

Baclofen and Diazepam

Baclofen acts within the spinal cord to reduce hyperactive reflexes.
Diazepam is a benzodiazepine used for spasticity.
Adverse impacts include sedation, but diazepam is used for this purpose as well.

Dantrolene

Direct-acting muscle relaxant.
Use this cautiously, as adverse effects can include liver damage.

Additional Treatment Options

Physical therapy, including stretching and flexibility exercises, can also help manage muscle spasms and spasticity.
Topical or other localized heat sources can also aid in muscle relief.

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Description

Explore the intricacies of central nervous system medications as covered in Chapters 12 and 14. Understand the role of neurotransmitters in functions such as memory, mood, and motor control, and learn about treatments for conditions like Parkinson's disease.