MCQ Quiz: Pharmacology of Drugs Used in Epilepsy

A thorough understanding of the pharmacology of drugs used in epilepsy is a cornerstone of neuropharmacology and a key component of thePatient Care VII: Brain and Behavior curriculum. This quiz is designed to test your knowledge of the diverse mechanisms of action, pharmacokinetic principles, and pharmacodynamic effects of anti-seizure medications (ASMs). From the complex kinetics of phenytoin to the novel targets of newer agents, a deep pharmacological understanding is essential for pharmacists to optimize therapy, manage side effects, and ensure patient safety.

1. A primary mechanism of action for many anti-seizure medications, including phenytoin and carbamazepine, is the blockade of which ion channels?

• A. Voltage-gated potassium channels
• B. T-type calcium channels
• C. Voltage-gated sodium channels
• D. Chloride channels

Answer: C. Voltage-gated sodium channels

2. How do benzodiazepines exert their anticonvulsant effect at the GABA-A receptor?

• A. They increase the duration of chloride channel opening.
• B. They increase the frequency of chloride channel opening in the presence of GABA.
• C. They directly block the chloride channel.
• D. They inhibit the reuptake of GABA.

Answer: B. They increase the frequency of chloride channel opening in the presence of GABA.

3. The pharmacology of ethosuximide makes it a first-line agent specifically for absence seizures because it selectively blocks:

• A. Voltage-gated sodium channels.
• B. High-voltage-activated L-type calcium channels.
• C. Low-voltage-activated T-type calcium channels.
• D. GABA-A receptors.

Answer: C. Low-voltage-activated T-type calcium channels.

4. The emergency management of status epilepticus involves the rapid administration of an IV benzodiazepine followed by a longer-acting agent. What is the pharmacological rationale for this sequence?

• A. The benzodiazepine provides rapid seizure termination, while the second agent provides longer-lasting prevention of recurrence.
• B. The second agent is used to reverse the benzodiazepine.
• C. The benzodiazepine is only for sedation.
• D. This sequence is no longer recommended.

Answer: A. The benzodiazepine provides rapid seizure termination, while the second agent provides longer-lasting prevention of recurrence.

5. Phenytoin exhibits non-linear, saturable (Michaelis-Menten) pharmacokinetics. This means that:

• A. Its half-life is constant regardless of the serum concentration.
• B. Once metabolic enzymes are saturated, a small dose increase can cause a large increase in serum concentration.
• C. Therapeutic drug monitoring is not required.
• D. The drug is not metabolized by the liver.

Answer: B. Once metabolic enzymes are saturated, a small dose increase can cause a large increase in serum concentration.

6. Levetiracetam has a novel mechanism of action that involves binding to which protein?

• A. The alpha-2-delta subunit of calcium channels
• B. The GABA-A receptor
• C. The synaptic vesicle protein 2A (SV2A).
• D. The NMDA receptor

Answer: C. The synaptic vesicle protein 2A (SV2A).

7. Valproic acid is considered a broad-spectrum anti-seizure medication due to its multiple mechanisms of action, which include sodium channel blockade and:

• A. Increasing the levels of the inhibitory neurotransmitter GABA.
• B. Selective dopamine reuptake inhibition.
• C. Agonism at the NMDA receptor.
• D. Selective blockade of T-type calcium channels only.

Answer: A. Increasing the levels of the inhibitory neurotransmitter GABA.

8. Phenobarbital exerts its anticonvulsant effect by binding to the GABA-A receptor and:

• A. Increasing the frequency of chloride channel opening.
• B. Decreasing the affinity of GABA for the receptor.
• C. Increasing the duration of chloride channel opening.
• D. Blocking the chloride channel.

Answer: C. Increasing the duration of chloride channel opening.

9. The unique pharmacokinetic property of carbamazepine that requires dose adjustments after the first few weeks of therapy is:

• A. Non-linear metabolism.
• B. Auto-induction of its own metabolism.
• C. Renal elimination without metabolism.
• D. High plasma protein binding.

Answer: B. Auto-induction of its own metabolism.

10. Gabapentin and pregabalin, while structurally related to GABA, do not act directly on GABA receptors. Their mechanism involves binding to:

• A. Voltage-gated sodium channels.
• B. The synaptic vesicle protein 2A (SV2A).
• C. The alpha-2-delta (α2δ) subunit of voltage-gated calcium channels.
• D. T-type calcium channels.

Answer: C. The alpha-2-delta (α2δ) subunit of voltage-gated calcium channels.

11. The “Transcending Concept: Pharmacokinetics” unit of the Patient Care VII course specifically highlights the complex kinetics of which three anti-seizure medications?

• A. Levetiracetam, Lamotrigine, and Lacosamide
• B. Phenytoin, Phenobarbital, and Valproic Acid.
• C. Ethosuximide, Zonisamide, and Topiramate
• D. Gabapentin, Pregabalin, and Vigabatrin

Answer: B. Phenytoin, Phenobarbital, and Valproic Acid.

12. Lacosamide is thought to have a novel mechanism of action that differs from other sodium channel blockers by:

• A. Enhancing the fast inactivation of voltage-gated sodium channels.
• B. Enhancing the slow inactivation of voltage-gated sodium channels.
• C. Blocking the channel from the intracellular side.
• D. Only blocking sodium channels in the resting state.

Answer: B. Enhancing the slow inactivation of voltage-gated sodium channels.

13. From a pharmacodynamic perspective, what is a common dose-related side effect of most anti-seizure medications?

• A. CNS depression (e.g., drowsiness, dizziness, ataxia)
• B. Hypertension
• C. Weight loss
• D. Increased alertness

Answer: A. CNS depression (e.g., drowsiness, dizziness, ataxia)

14. A patient taking phenytoin has a low serum albumin level. How will this affect the phenytoin concentration?

• A. It will decrease the total phenytoin level.
• B. It will increase the fraction of unbound (free) phenytoin, potentially leading to toxicity even with a “normal” total level.
• C. It will have no effect on the phenytoin level.
• D. It will increase the metabolism of phenytoin.

Answer: B. It will increase the fraction of unbound (free) phenytoin, potentially leading to toxicity even with a “normal” total level.

15. A key difference between focal and generalized seizures lies in their origin. Generalized seizures involve:

• A. Only one small area of the brain.
• B. Both cerebral hemispheres from the onset.
• C. Only the cerebellum.
• D. Only the brainstem.

Answer: B. Both cerebral hemispheres from the onset.

16. Vigabatrin is an anti-seizure medication that works by:

• A. Blocking sodium channels.
• B. Irreversibly inhibiting GABA transaminase, the enzyme that breaks down GABA.
• C. Blocking T-type calcium channels.
• D. Agonizing the NMDA receptor.

Answer: B. Irreversibly inhibiting GABA transaminase, the enzyme that breaks down GABA.

17. The primary reason for performing therapeutic drug monitoring (TDM) for a drug like phenytoin is its:

• A. Wide therapeutic index and predictable kinetics.
• B. Low cost.
• C. Narrow therapeutic index and high pharmacokinetic variability.
• D. Lack of side effects.

Answer: C. Narrow therapeutic index and high pharmacokinetic variability.

18. Topiramate’s pharmacological action as a weak carbonic anhydrase inhibitor is responsible for which potential side effects?

• A. Weight gain and sedation
• B. Metabolic acidosis and kidney stones
• C. Gingival hyperplasia
• D. Aplastic anemia

Answer: B. Metabolic acidosis and kidney stones

19. Which anti-seizure medication is a sulfonamide derivative, conferring a risk of hypersensitivity reaction in patients with a “sulfa allergy”?

• A. Topiramate
• B. Zonisamide
• C. Felbamate
• D. Lacosamide

Answer: B. Zonisamide

20. The “Implement” step of the Pharmacists’ Patient Care Process (PPCP) for a patient starting a new ASM would include:

• A. Assessing their seizure type.
• B. Counseling the patient on the importance of adherence and potential side effects.
• C. Developing the therapeutic plan.
• D. Collecting their medication history.

Answer: B. Counseling the patient on the importance of adherence and potential side effects.

21. A major pharmacodynamic advantage of newer ASMs over older agents is:

• A. A higher incidence of severe side effects.
• B. A generally more favorable side effect profile and fewer drug-drug interactions.
• C. A narrower spectrum of activity.
• D. More complex pharmacokinetics.

Answer: B. A generally more favorable side effect profile and fewer drug-drug interactions.

22. Which anti-seizure medication is known to cause gingival hyperplasia as a classic long-term side effect?

• A. Valproic acid
• B. Phenytoin
• C. Levetiracetam
• D. Lamotrigine

Answer: B. Phenytoin

23. The “pharmacology of drugs used in epilepsy” is a core unit in the

PHA5789C Patient Care course, demonstrating its clinical importance.

• A. True
• B. False

Answer: A. True

24. A patient taking carbamazepine (a CYP3A4 inducer) is started on an oral contraceptive (a CYP3A4 substrate). What is the potential pharmacologic outcome?

• A. Increased contraceptive levels, risking side effects.
• B. Decreased contraceptive levels, risking therapeutic failure (unintended pregnancy).
• C. No interaction will occur.
• D. Increased carbamazepine levels, risking toxicity.

Answer: B. Decreased contraceptive levels, risking therapeutic failure (unintended pregnancy).

25. A patient presents with nystagmus (involuntary eye movements). This is an early sign of toxicity for which anti-seizure medication?

• A. Gabapentin
• B. Levetiracetam
• C. Phenytoin
• D. Pregabalin

Answer: C. Phenytoin

26. The term “broad-spectrum” implies that an ASM like valproic acid or levetiracetam is effective against:

• A. Only absence seizures.
• B. Only focal seizures.
• C. Both focal and a variety of generalized seizures.
• D. Only tonic-clonic seizures.

Answer: C. Both focal and a variety of generalized seizures.

27. The use of IV fosphenytoin is preferred over IV phenytoin in some clinical situations because it causes less:

• A. Sedation.
• B. Seizure control.
• C. Hypotension and infusion-site reactions (e.g., purple glove syndrome).
• D. Cognitive slowing.

Answer: C. Hypotension and infusion-site reactions (e.g., purple glove syndrome).

28. Tiagabine exerts its anti-seizure effect via which unique mechanism?

• A. Binding to SV2A
• B. Inhibiting GABA reuptake by blocking GAT-1
• C. Blocking sodium channels
• D. Blocking T-type calcium channels

Answer: B. Inhibiting GABA reuptake by blocking GAT-1

29. A patient’s serum phenytoin level is reported as 15 mcg/mL. The lab’s reference range is 10-20 mcg/mL. This level is considered:

• A. Subtherapeutic
• B. Therapeutic
• C. Toxic
• D. Critically high

Answer: B. Therapeutic

30. The pharmacology of felbamate is complex, but its use is severely restricted due to the risk of:

• A. Gingival hyperplasia.
• B. Aplastic anemia and hepatic failure.
• C. Weight loss.
• D. Word-finding difficulties.

Answer: B. Aplastic anemia and hepatic failure.

31. The primary pharmacologic reason for tapering off any ASM rather than stopping abruptly is to prevent:

• A. Withdrawal seizures.
• B. Drug-drug interactions.
• C. Severe sedation.
• D. Liver damage.

Answer: A. Withdrawal seizures.

32. The mechanism of action of benzodiazepines is pharmacologically distinct from barbiturates in that benzodiazepines increase the _________ of channel opening, while barbiturates increase the _________.

• A. duration; frequency
• B. frequency; duration
• C. voltage; frequency
• D. frequency; voltage

Answer: B. frequency; duration

33. Which anti-seizure medication is commonly associated with dose-related behavioral side effects like irritability and aggression?

• A. Phenytoin
• B. Carbamazepine
• C. Levetiracetam
• D. Lamotrigine

Answer: C. Levetiracetam

34. The “Personalized Medicine for Epilepsy” lecture indicates the importance of testing for which allele before starting carbamazepine in certain populations?

• A. CYP2C19*2
• B. HLA-B*1502.
• C. VKORC1
• D. MTHFR

Answer: B. HLA-B*1502.

35. A “drug-drug-gene interaction” as taught in the curriculum, could occur in a CYP2C19 poor metabolizer taking phenytoin who is given:

• A. A CYP2C19 inducer.
• B. A CYP2C19 inhibitor like fluconazole.
• C. A drug that is not metabolized by CYP enzymes.
• D. A placebo.

Answer: B. A CYP2C19 inhibitor like fluconazole.

36. A key part of the “Follow-up and Monitor” step of the PPCP for a patient on valproic acid involves monitoring:

• A. Only seizure frequency.
• B. Seizure frequency, side effects, and laboratory parameters like LFTs and CBC.
• C. Only drug cost.
• D. Only the prescription refill date.

Answer: B. Seizure frequency, side effects, and laboratory parameters like LFTs and CBC.

37. Which anti-seizure medication is also commonly used for neuropathic pain?

• A. Ethosuximide
• B. Phenytoin
• C. Gabapentin
• D. Lamotrigine

Answer: C. Gabapentin

38. The pharmacology of most ASMs involves modulating ion channels or neurotransmitter balance to achieve what overall effect on the CNS?

• A. Increase neuronal excitability.
• B. Decrease neuronal excitability and raise the seizure threshold.
• C. Have no effect on neuronal activity.
• D. Increase the speed of nerve conduction.

Answer: B. Decrease neuronal excitability and raise the seizure threshold.

39. The high degree of plasma protein binding of phenytoin and valproic acid is a key pharmacokinetic consideration because:

• A. It makes the drugs safer.
• B. Only the unbound (free) fraction of the drug is pharmacologically active.
• C. It prevents the drugs from crossing the blood-brain barrier.
• D. It means no drug interactions can occur.

Answer: B. Only the unbound (free) fraction of the drug is pharmacologically active.

40. What is a primary pharmacological goal when selecting an ASM for a newly diagnosed patient?

• A. To use the most potent drug available, regardless of side effects.
• B. To achieve seizure control with monotherapy, if possible.
• C. To start with polytherapy immediately.
• D. To choose the drug with the most complex kinetics.

Answer: B. To achieve seizure control with monotherapy, if possible.

41. The use of a ketogenic diet in some pediatric epilepsy cases is a non-pharmacologic strategy thought to work by:

• A. Increasing neuronal excitability.
• B. Altering brain energy metabolism in a way that produces an anticonvulsant effect.
• C. Directly blocking sodium channels.
• D. Increasing GABA levels.

Answer: B. Altering brain energy metabolism in a way that produces an anticonvulsant effect.

42. The term “teratogenicity” refers to a drug’s potential to cause:

• A. Liver damage.
• B. Kidney damage.
• C. Birth defects.
• D. Cancer.

Answer: C. Birth defects.

43. Which ASM is also a mood stabilizer and requires slow titration to avoid a rash?

• A. Phenytoin
• B. Carbamazepine
• C. Lamotrigine
• D. Levetiracetam

Answer: C. Lamotrigine

44. A patient taking an enzyme-inducing ASM like phenobarbital may require _________ doses of other drugs that are substrates of the induced enzymes.

• A. lower
• B. the same
• C. higher
• D. less frequent

Answer: C. higher

45. What is the fundamental difference between epilepsy and a seizure?

• A. There is no difference.
• B. A seizure is a single event of abnormal neuronal discharge, while epilepsy is a chronic disease characterized by a predisposition to recurrent seizures.
• C. Epilepsy is a single event, while a seizure is a chronic disease.
• D. Epilepsy is only diagnosed in children.

Answer: B. A seizure is a single event of abnormal neuronal discharge, while epilepsy is a chronic disease characterized by a predisposition to recurrent seizures.

46. The pharmacology of benzodiazepines makes them useful for acute seizure termination but not for chronic monotherapy due to:

• A. Lack of efficacy.
• B. High cost.
• C. The development of tolerance to their anticonvulsant effects.
• D. Their route of administration.

Answer: C. The development of tolerance to their anticonvulsant effects.

47. The half-life of phenobarbital is very long (several days). This pharmacokinetic property means that:

• A. The drug must be dosed multiple times per day.
• B. It will reach a steady-state concentration very quickly.
• C. It will take a long time to reach steady-state and a long time to be eliminated from the body.
• D. It has no potential for drug interactions.

Answer: C. It will take a long time to reach steady-state and a long time to be eliminated from the body.

48. Why is it important to obtain a corrected phenytoin level in a patient with low albumin?

• A. Because the total level will accurately reflect the amount of active drug.
• B. Because the total level may be in the “therapeutic” range while the active, free level is actually toxic.
• C. Because low albumin increases phenytoin metabolism.
• D. Because low albumin prevents phenytoin from working.

Answer: B. Because the total level may be in the “therapeutic” range while the active, free level is actually toxic.

49. The “Assess” step of the PPCP for an epilepsy patient on carbamazepine would include reviewing:

• A. Seizure log, side effects, and recent CBC and LFT lab results.
• B. Only the patient’s name and date of birth.
• C. Only the cost of the medication.
• D. The pharmacy’s staffing schedule.

Answer: A. Seizure log, side effects, and recent CBC and LFT lab results.

50. The ultimate goal of understanding the pharmacology of ASMs is to:

• A. Memorize a list of drugs.
• B. Be able to rationally select and manage therapy to improve a patient’s quality of life.
• C. Pass a single exam.
• D. Only focus on the newest medications available.

Answer: B. Be able to rationally select and manage therapy to improve a patient’s quality of life.