Types of Seizures and Action Potential Modulation

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Questions and Answers

Which type of seizures typically results in a brief lapse of awareness without loss of posture?

  • Focal onset seizures
  • Myoclonic seizures
  • Absence seizures (correct)
  • Tonic-clonic seizures

What is a common adverse effect of both carbamazepine and oxcarbazepine?

  • Hyponatremia (correct)
  • Gingival hyperplasia
  • Respiratory depression
  • Weight gain

Which medication is considered first line for treating absence seizures?

  • Oxcarbazepine
  • Ethosuximide (correct)
  • Gabapentin
  • Lamotrigine

What is the mechanism of action of phenytoin in the treatment of seizures?

<p>Voltage gated Na+ channel inhibitor (B)</p> Signup and view all the answers

What adverse effect is specifically associated with lamotrigine?

<p>Rash and Stevens-Johnson syndrome (D)</p> Signup and view all the answers

Which seizure type is characterized by a rapid loss of muscle tone?

<p>Atonic seizures (B)</p> Signup and view all the answers

What is a notable adverse effect of benzodiazepines when suddenly withdrawn?

<p>Status epilepticus (D)</p> Signup and view all the answers

Which medication has a mechanism of action unrelated to GABA, despite its name?

<p>Gabapentin (A)</p> Signup and view all the answers

Phenytoin is particularly effective for which type of seizures?

<p>Tonic-clonic and focal-onset seizures (A)</p> Signup and view all the answers

What is a significant adverse effect of valproic acid?

<p>Metabolic interactions with drugs (A)</p> Signup and view all the answers

What is a primary action of calcium (Ca+) channel blockers in the treatment of seizures?

<p>Prevent absence seizures from occurring (B)</p> Signup and view all the answers

Which medication is noted for having a mechanism of action that includes inhibiting voltage-gated Na+ channels?

<p>Valproic acid (C)</p> Signup and view all the answers

What is a severe potential adverse effect associated with carbamazepine?

<p>Steven Johnson syndrome (A)</p> Signup and view all the answers

Why is it important to treat the cause of seizures?

<p>To control seizures and reduce their frequency (D)</p> Signup and view all the answers

What characterizes generalized onset seizures as more problematic than focal onset seizures?

<p>They involve irregular electrical activity across both hemispheres (D)</p> Signup and view all the answers

What is a characteristic adverse effect of lamotrigine?

<p>Stevens Johnson syndrome (B)</p> Signup and view all the answers

What effect does phenytoin have at therapeutic doses?

<p>Inhibits voltage-gated Na+ channels (A)</p> Signup and view all the answers

Which of the following drugs is primarily used to manage absence seizures?

<p>Ethosuximide (A)</p> Signup and view all the answers

What is a common side effect of benzodiazepines when used for managing status epilepticus?

<p>Respiratory depression (B)</p> Signup and view all the answers

What side effect is associated with long-term use of gabapentin?

<p>Weight gain (A)</p> Signup and view all the answers

What is the primary effect of blocking Na+ channels in the treatment of seizures?

<p>Slows down neuron firing (D)</p> Signup and view all the answers

Which medication is known to have higher risks for hyponatremia among antiepileptics?

<p>Oxcarbazepine (C)</p> Signup and view all the answers

What is a potential consequence of abruptly stopping benzodiazepines in patients with epilepsy?

<p>Status epilepticus (A)</p> Signup and view all the answers

Which adverse effect is associated with lamotrigine?

<p>Suicidal ideations (D)</p> Signup and view all the answers

What characterizes focal onset seizures compared to generalized onset seizures?

<p>They can remain within a single hemisphere. (C)</p> Signup and view all the answers

Which of the following medications is utilized for a broad range of seizure types, including generalized and myoclonic seizures?

<p>Valproic acid (B)</p> Signup and view all the answers

What is a characteristic feature of absence seizures?

<p>Lapses of awareness without loss of posture (A)</p> Signup and view all the answers

What is a notable adverse effect of the drug gabapentin?

<p>Weight gain (A)</p> Signup and view all the answers

What role do calcium (Ca+) channel blockers play in the management of seizures?

<p>Prevent absence seizures from occurring (D)</p> Signup and view all the answers

What is the mechanism of action of ethosuximide in treating seizures?

<p>Inhibits voltage gated Ca+ channels (C)</p> Signup and view all the answers

Flashcards

Action Potential Transmission

The speed at which electrical signals travel along neurons, impacting seizure activity.

Focal Onset Seizure

A seizure that starts in one part of the brain (one hemisphere)

Generalized Onset Seizure

Seizures that start throughout the brain, more widespread than focal.

Absence Seizure

A brief loss of awareness, often in childhood, characterized by a lapse without loss of posture.

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Tonic-Clonic Seizure

A seizure characterized by stiffening of muscles (tonic) followed by rhythmic jerking (clonic).

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Antiepileptic Adverse Effects

Side effects of anti-seizure drugs, can include suicidal thoughts, birth defects, and skin problems.

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Phenytoin MOA

Inhibits voltage-gated sodium channels, slowing repetitive neuronal firing.

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Valproic Acid MOA

Inhibits sodium and calcium channels, and may stimulates GABA synthesis, to stop seizures.

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Ethosuximide MOA

Blocks calcium channels in neurons that prevents certain seizures from occuring

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Benzodiazepines MOA

Are positive allosteric modulators of GABA receptors, enhancing GABA action to treat seizures.

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What is the effect of slowing down Na+ channels?

Slowing down Na+ channels slows down the transmission of action potentials and can suppress seizures.

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How do Ca+ channel blockers treat absence seizures?

Ca+ channel blockers target the hypothalamus, an area involved in absence seizures, to prevent these seizures.

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What is the difference between focal and generalized seizures?

Focal seizures affect one hemisphere of the brain, while generalized seizures involve the whole brain.

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What is the mechanism of Phenytoin?

Phenytoin inhibits voltage-gated Na+ channels, slowing down repetitive neuronal firing and reducing seizure activity.

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What are the primary effects of Carbamazepine?

Carbamazepine blocks voltage-gated Na+ channels to slow down neuron firing and reduce seizure activity, primarily targeting focal and tonic-clonic seizures.

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What drug is traditionally used for absent seizures?

Ethosuximide is a first-line treatment for absent seizures, blocking calcium channels to prevent these seizures.

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Why is Valproic Acid considered a 'broad-spectrum' antiepileptic?

Valproic acid can treat various seizure types by targeting multiple mechanisms, including Na+ and Ca+ channels, and boosting GABA levels.

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What are benzodiazepines used for in epilepsy?

Benzodiazepines enhance the effects of GABA, calming the brain to treat seizures, particularly status epilepticus and alcohol withdrawal seizures.

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What are some common adverse effects of antiepileptic medications?

Antiepileptic drugs can have side effects such as suicidal thoughts, birth defects, skin problems, and drug interactions.

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Action Potential and Seizures

Action potentials are electrical signals that travel along neurons. Slowing down sodium channels (Na+) decreases these signals, which can reduce seizure activity.

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Calcium Channels and Absence Seizures

Calcium channels (Ca+) in the hypothalamus are involved in controlling absence seizures. Blocking these channels can prevent these seizures.

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Focal vs. Generalized Seizures

Focal seizures start in one part of the brain and may not spread, while generalized seizures affect the whole brain.

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Carbamazepine MOA

Carbamazepine also targets sodium channels (Na+), slowing down neuron firing and reducing seizure activity.

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Valproic Acid: Broad Spectrum

Valproic acid can treat various seizure types by working on multiple targets: sodium channels (Na+), calcium channels (Ca+), and increasing GABA levels.

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GABA and Benzodiazepines

Benzodiazepines enhance the effects of GABA, a calming neurotransmitter, which reduces seizure activity.

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Common Antiepileptic Adverse Effects

Anti-seizure medications can have side effects like suicidal thoughts, birth defects, skin problems, and drug interactions.

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Study Notes

Types of Seizures

  • Focal onset seizures: Stay within one hemisphere of the brain. May or may not involve impaired awareness.
  • Generalized onset seizures: More problematic, originating in core brain areas (thalamus or brainstem), transmitting signals throughout the brain.
  • Absence seizures: Characterized by a brief lapse of awareness (seconds), without loss of posture. Typically childhood onset and resolve in adulthood. Breathing can stop briefly.
  • Tonic-clonic seizures: Involve muscle stiffness followed by rhythmic jerking movements.
  • Atonic seizures: Sudden, rapid loss of muscle tone.
  • Myoclonic seizures: Brief, sudden muscle contractions.

Action Potential and Channel Modulation

  • Sodium (Na+) channels are crucial for action potentials. Slowing Na+ channels can slow action potential transmission and suppress seizures.
  • Calcium (Ca+) channels are targeted for absence seizure treatment. Blocking Ca+ channels in the hypothalamus can prevent these seizures.

Antiepileptic Drugs (AEDs) and Adverse Effects

  • AEDs aim to control seizures, not cure them.
  • Common adverse effects: Increased suicidal thoughts, fetal abnormalities, dermatological issues (rashes, Stevens-Johnson syndrome).

Antiepileptic Drug Mechanisms and Uses

  • Phenytoin: Inhibits voltage-gated Na+ channels; slows repetitive firing; treats tonic-clonic and focal onset seizures. Adverse effects include gingival hyperplasia and interactions with other drugs.
  • Carbamazepine: Inhibits voltage-gated Na+ channels; slows neuron firing; treats focal, focal bilateral and tonic-clonic seizures. Adverse effects: hyponatremia, skin issues, Stevens-Johnson syndrome and drug interactions.
  • Oxcarbazepine: Similar to carbamazepine but primarily for focal seizures. Higher risk of hyponatremia, fewer drug interactions, better tolerated.
  • Lamotrigine: Inhibits Na+ channels, effective for focal, generalized and tonic-clonic seizures. Adverse effects include suicidal ideation, and Stevens-Johnson syndrome.
  • Levetiracetam: Mechanism unknown; treats focal, tonic-clonic, generalized, and myoclonic seizures. Adverse effects include mood and behavior changes.
  • Valproic acid: Broad-spectrum AED affecting multiple channels (Na+, Ca+, and influencing GABA); treats generalized, tonic-clonic and myoclonic seizures. Adverse effects: toxicity, liver problems (hepatotoxicity), pancreatitis, pregnancy concerns and metabolic interactions with other medications.
  • Ethosuximide: Targets voltage-gated Ca+ channels, first line treatment for absence seizures. Better tolerated.
  • Gabapentin: Blocks voltage-gated Ca+ and K+channels; used for focal and tonic seizures, neuropathic pain, and migraine. Well tolerated.
  • Pregabalin: Similar mechanism to gabapentin, used for similar applications, but potentially higher risk of adverse effects (weight gain and dry mouth).
  • Benzodiazepines: Positive allosteric modulators of GABA receptors. Uses: managing status epilepticus and alcohol withdrawal. Significant adverse effects (sedation, anesthesia, lethargy, behavior problems, GI upset). Sudden withdrawal may increase risk of status epilepticus.
  • Drug group ending in "PAM" (e.g. Diazepam) used to manage status epilepticus. Significant adverse effects include respiratory depression.

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