Antiepileptic drugs (AEDs) are central to managing epilepsy and related seizure disorders. This concise, targeted introduction for B. Pharm students covers classification, mechanisms of action, pharmacokinetics, therapeutic uses, adverse effects, drug interactions and principles of monotherapy versus polytherapy. Key AED classes include sodium-channel blockers (phenytoin, carbamazepine), GABA enhancers (benzodiazepines, phenobarbital), broad-spectrum agents (valproate, levetiracetam), and newer drugs (lamotrigine, lacosamide). Emphasis is on dosing, therapeutic drug monitoring, pregnancy considerations, and hepatic/renal metabolism—critical for safe dispensing and patient counseling. Practical MCQs will reinforce drug profiles, mechanisms, side-effect patterns and interaction risks clinically. ‘Now let’s test your knowledge with 30 MCQs on this topic.’
Q1. Which is the primary mechanism of action of phenytoin?
- Enhances GABAergic neurotransmission
- Blocks voltage-gated sodium channels (use-dependent)
- Inhibits T-type calcium channels
- Binds SV2A synaptic vesicle protein
Correct Answer: Blocks voltage-gated sodium channels (use-dependent)
Q2. Which antiepileptic drug is a potent hepatic enzyme inducer and shows autoinduction of its metabolism?
- Valproate
- Lamotrigine
- Carbamazepine
- Levetiracetam
Correct Answer: Carbamazepine
Q3. Which drug is the treatment of choice for typical absence seizures?
- Phenytoin
- Carbamazepine
- Ethosuximide
- Phenobarbital
Correct Answer: Ethosuximide
Q4. Which antiepileptic drug is most strongly associated with hepatotoxicity and teratogenicity (neural tube defects)?
- Valproate
- Lamotrigine
- Levetiracetam
- Gabapentin
Correct Answer: Valproate
Q5. Which AED requires routine serum level monitoring due to a narrow therapeutic window and nonlinear kinetics?
- Levetiracetam
- Gabapentin
- Phenytoin
- Lamotrigine
Correct Answer: Phenytoin
Q6. What is the primary molecular target of levetiracetam?
- Voltage-gated sodium channels
- GABA transaminase
- Synaptic vesicle protein 2A (SV2A)
- T-type calcium channels
Correct Answer: Synaptic vesicle protein 2A (SV2A)
Q7. Which antiepileptic drug can worsen absence seizures?
- Ethosuximide
- Carbamazepine
- Valproate
- Benzodiazepines
Correct Answer: Carbamazepine
Q8. Which AED is considered broad-spectrum and often first-line for generalized tonic-clonic seizures?
- Ethosuximide
- Carbamazepine
- Valproate
- Phenytoin
Correct Answer: Valproate
Q9. Which drug irreversibly inhibits GABA transaminase, increasing CNS GABA levels?
- Tiagabine
- Vigabatrin
- Levetiracetam
- Lacosamide
Correct Answer: Vigabatrin
Q10. Which AED is commonly associated with gingival hyperplasia as an adverse effect?
- Phenytoin
- Carbamazepine
- Valproate
- Levetiracetam
Correct Answer: Phenytoin
Q11. Which antiepileptic requires slow titration due to a significant risk of rash and Stevens-Johnson syndrome, especially when combined with valproate?
- Lamotrigine
- Gabapentin
- Levetiracetam
- Ethosuximide
Correct Answer: Lamotrigine
Q12. What is a major action of lamotrigine relevant to seizure control?
- Potentiates GABA-A receptor opening frequency
- Inhibits T-type calcium channels selectively
- Blocks voltage-gated sodium channels and reduces glutamate release
- Irreversibly inhibits GABA transaminase
Correct Answer: Blocks voltage-gated sodium channels and reduces glutamate release
Q13. Which antiepileptic is generally considered safer for use during pregnancy compared with valproate?
- Valproate
- Lamotrigine
- Phenobarbital
- Topiramate
Correct Answer: Lamotrigine
Q14. Which antiepileptic drug is excreted largely unchanged by the kidneys and requires dose adjustment in renal impairment?
- Gabapentin
- Carbamazepine
- Phenytoin
- Valproate
Correct Answer: Gabapentin
Q15. Ethosuximide exerts its antiepileptic effect primarily by blocking which channels?
- N-type calcium channels
- T-type calcium channels
- Voltage-gated sodium channels
- GABA-A chloride channels
Correct Answer: T-type calcium channels
Q16. Which antiepileptic is contraindicated in acute intermittent porphyria and is considered porphyrogenic?
- Phenobarbital
- Valproate
- Levetiracetam
- Lamotrigine
Correct Answer: Phenobarbital
Q17. Which AED has been linked to progressive, irreversible visual field constriction as a serious adverse effect?
- Vigabatrin
- Ethosuximide
- Lamotrigine
- Pregabalin
Correct Answer: Vigabatrin
Q18. Co-administration of which drug markedly increases lamotrigine plasma levels and risk of rash?
- Carbamazepine
- Valproate
- Phenytoin
- Levetiracetam
Correct Answer: Valproate
Q19. What is the usual therapeutic plasma concentration range for total phenytoin?
- 1–5 µg/mL
- 5–10 µg/mL
- 10–20 µg/mL
- 20–30 µg/mL
Correct Answer: 10–20 µg/mL
Q20. How do benzodiazepines (e.g., lorazepam) exert anticonvulsant effects?
- Block voltage-gated sodium channels
- Enhance GABA-A receptor-mediated chloride influx
- Inhibit glutamate NMDA receptors directly
- Irreversibly inhibit GABA transaminase
Correct Answer: Enhance GABA-A receptor-mediated chloride influx
Q21. Which AED is particularly effective for myoclonic seizures?
- Ethosuximide
- Valproate
- Carbamazepine
- Phenytoin
Correct Answer: Valproate
Q22. Which antiepileptic drug carries a risk of serious hematologic toxicity including aplastic anemia?
- Carbamazepine
- Levetiracetam
- Gabapentin
- Ethosuximide
Correct Answer: Carbamazepine
Q23. What is the first-line intravenous medication for immediate control of status epilepticus?
- Intravenous lorazepam (benzodiazepine)
- Oral carbamazepine
- Intravenous phenytoin as initial monotherapy
- Oral valproate
Correct Answer: Intravenous lorazepam (benzodiazepine)
Q24. Pregabalin and gabapentin reduce excitatory neurotransmitter release by binding to what target?
- NMDA receptor glycine site
- Alpha-2-delta subunit of voltage-gated calcium channels
- SV2A synaptic vesicle protein
- T-type calcium channels
Correct Answer: Alpha-2-delta subunit of voltage-gated calcium channels
Q25. Which antiepileptic drug is the first-line therapy for trigeminal neuralgia?
- Lamotrigine
- Carbamazepine
- Valproate
- Levetiracetam
Correct Answer: Carbamazepine
Q26. Which antiepileptic commonly causes weight gain as an adverse effect?
- Valproate
- Topiramate
- Lamotrigine
- Levetiracetam
Correct Answer: Valproate
Q27. Which AED is known to inhibit hepatic metabolism and can raise levels of co-administered drugs?
- Carbamazepine (strong inducer)
- Valproate (hepatic enzyme inhibitor)
- Phenytoin (only inhibitor)
- Levetiracetam (CYP inhibitor)
Correct Answer: Valproate (hepatic enzyme inhibitor)
Q28. HLA-B*1502 genetic testing is recommended before starting which AED in certain Asian populations due to SJS risk?
- Lamotrigine
- Carbamazepine
- Valproate
- Levetiracetam
Correct Answer: Carbamazepine
Q29. Which drug is generally ineffective for focal (partial) seizures and is mainly used for absence seizures?
- Ethosuximide
- Carbamazepine
- Phenytoin
- Levetiracetam
Correct Answer: Ethosuximide
Q30. Which class of AEDs can reduce the effectiveness of oral contraceptives by inducing hepatic enzymes?
- Enzyme-inducing AEDs such as carbamazepine and phenytoin
- Non-enzyme-inducing AEDs such as levetiracetam
- GABA-transaminase inhibitors such as vigabatrin
- SV2A binders such as levetiracetam
Correct Answer: Enzyme-inducing AEDs such as carbamazepine and phenytoin
I am a Registered Pharmacist under the Pharmacy Act, 1948, and the founder of PharmacyFreak.com. I hold a Bachelor of Pharmacy degree from Rungta College of Pharmaceutical Science and Research. With a strong academic foundation and practical knowledge, I am committed to providing accurate, easy-to-understand content to support pharmacy students and professionals. My aim is to make complex pharmaceutical concepts accessible and useful for real-world application.
Mail- Sachin@pharmacyfreak.com