Antiepileptic Drugs and Lithium Management

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Questions and Answers

Which of the following antiepileptic drugs primarily enhances the affinity of receptors toward GABA?

Valproic acid

Phenytoin

Tiagabine

Phenobarbital (correct)

Which drug inhibits the reuptake of GABA?

Topiramate

Clonazepam

Felbamate

Tiagabine (correct)

What is the primary mechanism of action of valproic acid in the context of epilepsy treatment?

Inhibiting GABA transaminase (correct)

Direct receptor agonism

Decreasing glutamate release

Stimulating GABA release

Which of the following statements is true regarding antiepileptic drugs?

They suppress seizures without affecting normal brain function. Signup and view all the answers

What is the primary reason for monitoring lithium levels in patients?

Lithium has a narrow therapeutic index. Signup and view all the answers

Which statement accurately describes Primidone's mechanism of action?

It is a prodrug that is metabolized to phenobarbital. Signup and view all the answers

Which of the following is a known side effect of lithium treatment?

Polydipsia Signup and view all the answers

What mechanism of action is proposed for lithium in treating bipolar disorders?

Decreases central cAMP and IP3 formation Signup and view all the answers

Which of the following antidepressants has been shown to have fewer adverse effects than traditional prescription antidepressants?

Hypericum extracts Signup and view all the answers

What is the primary therapeutic use of lithium?

Management of bipolar disorders Signup and view all the answers

What effect does high doses of catecholamines have on the pupils?

Stimulates mydriasis Signup and view all the answers

Which drug interaction could lead to a hypertensive crisis in patients taking levodopa?

Levodopa with nonselective MAO inhibitors Signup and view all the answers

What is a primary advantage of dopamine receptor agonists over levodopa in treating Parkinson's disease?

They do not rely on presynaptic conversion to dopamine Signup and view all the answers

What adverse effect is commonly associated with dopamine receptor agonists?

Pulmonary fibrosis Signup and view all the answers

Which statement about the side effects of dopamine receptor agonists is true?

They can cause more neuropsychiatric disorders than levodopa Signup and view all the answers

What precaution should be taken when administering bromocriptine to patients?

It may worsen conditions in patients with peripheral vascular disease Signup and view all the answers

When are dopamine receptor agonists typically used in the management of Parkinson's disease?

As initial therapy in mild PD or as adjuncts in advanced PD Signup and view all the answers

Which of the following drugs is an ergotamine derivative that may cause vasoconstriction?

Bromocriptine Signup and view all the answers

What is the primary characteristic of akathisia?

Inability to sit still or motor restlessness Signup and view all the answers

Which condition occurs as a delayed response following chronic treatment with antipsychotics?

Tardive dyskinesia Signup and view all the answers

What is a key treatment for managing akathisia?

β blockers Signup and view all the answers

How does tardive dyskinesia differ from other extrapyramidal symptoms (EPS)?

It is considered a chronic EPS and is often irreversible Signup and view all the answers

Which type of antipsychotics is associated with fewer motor disturbances?

Atypical antipsychotics Signup and view all the answers

What effect is caused by blocking D2 receptors in the anterior pituitary?

Increased prolactin levels Signup and view all the answers

What serious condition is associated with Felbamate that limits its use to refractory epilepsies?

Hepatic failure Signup and view all the answers

What are common symptoms of hyperprolactinemia in females?

Amenorrhea and galactorrhea Signup and view all the answers

Which medication can cause serious rashes that may escalate to life-threatening reactions?

Lamotrigine Signup and view all the answers

Which of the following is true regarding the management of tardive dyskinesia?

Prolonged holidays from antipsychotics may reduce symptoms Signup and view all the answers

What common side effect does Phenytoin produce, particularly in elderly patients?

Gingival hyperplasia Signup and view all the answers

Which of the following antiepileptic drugs is known to cause visual field defects that require monitoring?

Vigabatrin Signup and view all the answers

Which medication is confirmed to be teratogenic and may lead to neural tube defects?

Valproic acid Signup and view all the answers

What potential long-term effect can arise from the chronic use of Phenytoin?

Peripheral neuropathies Signup and view all the answers

Which drug is contraindicated in patients who have hypersensitivity to sulfonamides?

Zonisamide Signup and view all the answers

Which class of antiepileptic drugs can reduce bone mineral density, leading to a risk of osteoporosis?

Hydantoins Signup and view all the answers

What is a natural opioid agonist derived from the poppy plant?

Codeine Signup and view all the answers

Which opioid is known to produce the most potent analgesic effects?

Morphine Signup and view all the answers

Which statement is accurate regarding the pharmacological effects of morphine?

It can lead to respiratory depression. Signup and view all the answers

What are the central nervous system effects of opioid agonists like morphine?

Nausea and vomiting. Signup and view all the answers

Which opioid classification includes heroin and hydromorphone?

Semisynthetic opioids Signup and view all the answers

What common peripheral effect can morphine induce due to local histamine release?

Cutaneous vasodilatation Signup and view all the answers

Which action by morphine can directly affect the respiratory system?

Depression of the medullary respiratory center Signup and view all the answers

Which side effect of morphine is associated with potential increases in intracranial pressure?

Respiratory depression Signup and view all the answers

Study Notes

Drugs Affecting the Central Nervous System

Drugs are used to manage neurodegenerative diseases.
Neurodegenerative diseases cause neuronal damage in certain brain areas.
Causes of neuronal damage include excessive excitotoxicity, stroke, head trauma, oxidative stress, and apoptosis (programmed cell death).
It is difficult to treat neurodegenerative diseases because CNS neurons cannot divide or regenerate.

Dopaminergic Neural Pathways

Dopamine (DA) is a precursor to norepinephrine (NE).
Dopamine pathways in the CNS include the nigrostriatal tract, and the mesolimbic-mesocortical tracts, for example, impacting movement & cognitive function.
The tuberoinfundibular pathway regulates prolactin in the pituitary.
The chemoreceptor trigger zone, in the medulla, ↑ emmisis when activated by DA receptors.
There are different pathways affecting different neurotransmitters

Parkinson's Disease

Second common neurodegenerative disease after Alzheimer's disease.
Definition: a progressive disorder affecting muscle movements
4 Cardinal motor features: Resting tremors, muscular rigidity, bradykinesia, and abnormal posture/gait.
Occurs predominantly in elderly above 65
Non-motor symptoms include depression, dementia, and sleep disturbance.
Etiology: DA neuron degeneration relative to excitatory cholinergic neurons in the nigrostriatal tract.

Parkinson's Management and Classification

Treatment goal: to balance DA and Ach in basal ganglia.
Primary: idiopathic Parkinson's disease
Secondary: Atypical Parkinsonism (vascular, toxin-induced, infectious, drug-induced)
Classification: Primary (Idiopathic), Secondary (Atypical)

Treatment of Parkinson's Disease

Dopaminergic drugs (e.g., levodopa).
Dopamine receptor agonists.
Dopamine releasers.
Selective MAO-B inhibitors (important to note peripheral dopa decarboxylase inhibitors).
Carbidopa as a peripheral dopa decarboxylase inhibitor.
Entacapone as a peripheral COMT inhibitor.

Learning Objectives (General)

Demonstrate understanding of dopaminergic neural pathways.
Classify antiparkinsonian drugs.
Compare the mechanism of action and side effects of antiparkinsonian drugs.

COMT Inhibitors (Treatment)

Entacapone and tolcapone are used to protect levodopa from destruction by COMT, increasing its availability to the CNS
Tolcapone causes hepatotoxicity, so is only used if other treatments are unsuccessful

Anticholinergic Drugs (Treatment)

Used to address the imbalance of ACh and DA.
Used as adjunctive therapy.

Antipsychotics

First generation : Phenothiazines, Thioxanthenes, Butyrophenones, Substituted benzamides
Second generation: Risperidone, Ziprasidone, Aripiprazole, Brexpiprazole, Clozapine
Mechanism of action:
Block DA, 5-HT receptors in the mesolimbic system
Extrapyramidal symptoms (EPS) can occur due to D2 blockade in the nigrostriatal pathway, affecting movement

Anti-Parkinsonian Medications and Their Interactions with Other Drugs

Levodopa: should be taken with peripheral decarboxylase inhibitors to minimize peripheral metabolism that reduces the amount of levodopa reaching the brain.
Other interaction details are present in the text. (The user should cross-reference with the relevant text)

Dopamine Receptor Agonists

Drugs that directly stimulate DA receptors.
Advantages: less fluctuations in motor symptoms compared to levodopa.
Used in early stages or as adjuncts for patients with advanced PD who experience on-off phenomena.

Drugs Inducing Dopamine Release

Amantadine: increases release and decreases reuptake of dopamine
Used early in Parkinson's treatment.

Monoamine Oxidase B Inhibitors

Selegiline (deprenyl): an irreversible, selective inhibitor of MAOB that inhibits dopamine breakdown.
Used in early/mild PD, alone or with levodopa

Miscellaneous (Treatment)

Apomorphine: s.c injection for "off" periods.
Pramipexole & Ropinirole: orally administered
Rotigotine: Daily transdermal patch

Alzheimer's Disease

Second common neurodegenerative disease after Parkinson’s Disease.
Symptoms: loss of intellectual ability and learning deficit.
Etiology: formation of plaques (β-amyloid), neurofibrillary tangles and degeneration of cholinergic neurons
Treatment: no effective therapy.

Acetylcholinesterase Inhibitors (Alzheimer's)

Donepezil (Aricept®), galantamine, rivastigmine.
Prevent breakdown of ACh

NMDA Receptor Antagonist (Alzheimer's)

Memantine
Blocks NMDA receptors, limiting Ca2+ influx.

Aducanumab (Alzheimer's)

Amyloid beta-directed monoclonal antibody.
Administered intravenously.
Reduces amyloid plaques.

Specific Treatment for Peptic Ulcer

Antibiotics
H2-receptor antagonists: Cimetidine ,Ranitidine (withdrawn), Famotidine, Nizatidine
Proton pump inhibitors (PPIs): Lansoprazole, Dexlansoprazole, Esomeprazole, Omeprazole, Pantoprazole
Prostaglandins: Misoprostol
Antacids: Aluminum hydroxide, Magnesium hydroxide, and Calcium carbonate
Sucralfate: Mucosal Protective Agent
Other Agents: Bismuth subsalicylate

Vomiting

Emesis or vomiting is the physiologic response to the presence of irritating or potentially harmful substances in the gut or bloodstream
Caused by excessive vestibular stimulation (motion sickness), or psychological stimuli (fear, dread, or obnoxious sights/odors)
Initiated by the vomiting/emesis center in the medulla.
Vomiting involves coordinated events: orally migrating intestinal contractions (reverse peristalsis), gastric contractions, diaphragmatic and abdominal wall contractions, relaxation of the esophageal sphincter and wall

Treatment for Vomiting

Antihistamines (e.g., dimenhydrinate)
Anticholinergics (e.g., scopolamine)
Serotonin antagonists (e.g., ondansetron)
Dopamine antagonists (e.g., metoclopramide)
NK-1 receptor antagonists (e.g., aprepitant)
Corticosteroids (e.g., dexamethasone)

Chemotherapy-Induced Nausea and Vomiting (CINV)

Nearly 70% to 80% of patients experience nausea and/or vomiting.
Treatment uses: Serotonin and NK-1 receptor antagonists, corticosteroids

Asthma

Chronic airway narrowing due to hyper-responsive airways.
Recurrent bouts of shortness of breath, chest tightness, wheezing, and coughing.
Physiologically: Reversible narrowing.
Pathologically: inflammation of the bronchial mucosa, increased lymphocytes, eosinophils, & mast cells

Etiology of Asthma

Genetic factors (family history of atopy, allergen sensitization)
Environmental factors (environmental exposure, maternal smoking)

Factors Triggering Asthma

Respiratory infection (viruses, bacteria, URT infections)
Allergens (grass, trees, weeds)
Environment (cold air)
Use of drugs (aspirin, NSAIDs, β-blockers)
Exercise
GERD (gastroesophageal reflux disease)
Emotional factors

Management of Asthma

Beta-2 Adrenoceptor Agonists (e.g., albuterol, salmeterol) for bronchodilation
Glucocorticoids (e.g., beclomethasone, fluticasone) for inflammation suppression.
Leukotriene antagonists (e.g., montelukast, zafirlukast)

Anti-IgE Treatment in Allergy

Omalizumab
Selectively binds to human IgE, inhibiting its binding to mast cells and basophils, reducing mediator release.

Drug-Induced Asthma

Non-selective β-blockers, parasympathomimetics, histamine releasers (e.g., morphine) can induce asthma.

Chronic Obstructive Pulmonary Disease (COPD)

Chronic and irreversible airflow obstruction, often linked to smoking and involving emphysema and chronic bronchitis.

COPD Symptoms

Fibrosis & destruction of alveoli and elastin fibers.
Obstruction by proteases including elastase.
Emphysema causes respiratory failure.
Unlike asthma, COPD is generally irreversible.

COPD Treatment

Cessation of smoking remains the most important treatment.
Β2 agonists or anticholinergics (or both).
Oral glucocorticoids (for acute exacerbations).
Inhaled corticosteroids.
Immunization against influenza and pneumococcus.

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Description

Test your knowledge about the mechanisms and effects of antiepileptic drugs, particularly their interactions with GABA and lithium monitoring in bipolar disorder treatment. This quiz covers key concepts, drug actions, and side effects, ensuring a comprehensive understanding of these essential medications.