Succinimides – Ethosuximide MCQs With Answer

Succinimides – Ethosuximide MCQs With Answer

Succinimides, especially ethosuximide, are essential anticonvulsants studied in B. Pharm programs for their role in treating absence seizures. This concise guide covers chemistry, mechanism (T‑type calcium channel blockade), pharmacokinetics, therapeutic monitoring, dosing, adverse effects, interactions (notably with valproate), and clinical use. The MCQs below are designed to deepen understanding of pharmacology, metabolism, clinical application, and safety monitoring of ethosuximide, helping students master both theory and practical points for examinations and dispensing. Now let’s test your knowledge with 50 MCQs on this topic.

Q1. Which clinical seizure type is ethosuximide primarily indicated for?

• Generalized tonic‑clonic seizures
• Focal (partial) seizures
• Absence (petit mal) seizures
• Myoclonic seizures

Correct Answer: Absence (petit mal) seizures

Q2. What is the primary mechanism of action of ethosuximide?

• Enhancement of GABAergic inhibition
• Blockade of T‑type (low‑threshold) calcium channels in thalamic neurons
• Inhibition of voltage‑gated sodium channels
• NMDA receptor antagonism

Correct Answer: Blockade of T‑type (low‑threshold) calcium channels in thalamic neurons

Q3. Ethosuximide belongs to which chemical class?

• Hydantoin derivatives
• Barbiturates
• Succinimide derivatives
• Benzodiazepines

Correct Answer: Succinimide derivatives

Q4. Which brand name is most commonly associated with ethosuximide?

• Depakote
• Zarontin
• Neurontin
• Tegretol

Correct Answer: Zarontin

Q5. The therapeutic plasma concentration range commonly cited for ethosuximide is approximately:

• 1–5 µg/mL
• 10–20 µg/mL
• 40–100 µg/mL
• 200–400 µg/mL

Correct Answer: 40–100 µg/mL

Q6. Which organ system is primarily responsible for metabolism of ethosuximide?

• Renal tubular secretion
• Hepatic microsomal oxidation (liver)
• Gastrointestinal degradation
• Pulmonary elimination

Correct Answer: Hepatic microsomal oxidation (liver)

Q7. A common early adverse effect of ethosuximide that patients often report is:

• Hepatic failure
• Gastrointestinal upset (nausea, abdominal pain)
• Severe neutropenia in all patients
• Renal colic

Correct Answer: Gastrointestinal upset (nausea, abdominal pain)

Q8. Which laboratory tests are important to monitor during ethosuximide therapy?

• Serum creatine kinase only
• CBC, liver function tests and serum drug level when indicated
• Fasting glucose and HbA1c only
• Coagulation profile only

Correct Answer: CBC, liver function tests and serum drug level when indicated

Q9. Co‑administration of which drug is known to increase ethosuximide plasma levels and risk toxicity?

• Rifampicin
• Carbamazepine
• Valproic acid
• Phenobarbital

Correct Answer: Valproic acid

Q10. Which statement about ethosuximide’s efficacy is correct?

• Highly effective for focal seizures with impaired awareness
• First‑line therapy for typical absence seizures in children
• Preferred for tonic‑clonic seizures as monotherapy
• Has strong anxiolytic properties

Correct Answer: First‑line therapy for typical absence seizures in children

Q11. Ethosuximide primarily reduces neuronal excitability by acting on which type of ion current?

• Persistent sodium current
• High‑voltage activated L‑type calcium current
• Low‑threshold T‑type calcium current
• Potassium inward rectifier current

Correct Answer: Low‑threshold T‑type calcium current

Q12. The most appropriate statement about ethosuximide dosing considerations is:

• Must be given intravenously for efficacy
• Oral dosing with gradual titration reduces adverse effects
• No need for titration; single high dose is recommended
• Only topical formulations are available

Correct Answer: Oral dosing with gradual titration reduces adverse effects

Q13. Which succinimide is considered a related drug to ethosuximide and sometimes used when ethosuximide is not tolerated?

• Methsuximide
• Levetiracetam
• Gabapentin
• Topiramate

Correct Answer: Methsuximide

Q14. Which adverse hematologic effect has been reported with ethosuximide therapy?

• Hemophilia
• Leukopenia or eosinophilia
• Polycythemia vera
• Hemochromatosis

Correct Answer: Leukopenia or eosinophilia

Q15. Which route of administration is the standard for ethosuximide therapy?

• Oral (capsules or syrup)
• Intramuscular injection
• Transdermal patch
• Inhalation aerosol

Correct Answer: Oral (capsules or syrup)

Q16. In case of ethosuximide overdose, the most appropriate initial management is:

• Immediate hemodialysis as first step for all patients
• Supportive care and symptomatic management; no specific antidote
• Administer naloxone to reverse toxicity
• Give high‑dose vitamin K

Correct Answer: Supportive care and symptomatic management; no specific antidote

Q17. Which monitoring parameter is most useful when adjusting ethosuximide therapy for efficacy and toxicity?

• Serum ethosuximide concentration
• Serum calcium concentration
• Urine ketones
• Blood ammonia

Correct Answer: Serum ethosuximide concentration

Q18. Ethosuximide’s elimination half‑life in adults is best described as:

• Very short, less than 2 hours
• Moderate, about 6–8 hours
• Relatively long, around 30–60 hours
• Extremely long, several months

Correct Answer: Relatively long, around 30–60 hours

Q19. Which of the following is NOT a typical adverse effect of ethosuximide?

• Drowsiness and fatigue
• Anorexia and weight loss
• Severe urinary retention as a common effect
• Headache and dizziness

Correct Answer: Severe urinary retention as a common effect

Q20. Which statement best describes ethosuximide’s effect on sodium channels?

• Primary potent blocker of voltage‑gated sodium channels
• No effect on ion channels; acts on GABA transporters
• Minimal effect on sodium channels; primary action on T‑type calcium channels
• Enhances sodium influx to hyperpolarize neurons

Correct Answer: Minimal effect on sodium channels; primary action on T‑type calcium channels

Q21. Which patient population requires careful consideration because of shorter ethosuximide half‑life and possible need for higher mg/kg dosing?

• Elderly patients
• Pregnant women
• Infants and young children
• Patients with chronic liver disease

Correct Answer: Infants and young children

Q22. Ethosuximide should be used with caution or avoided in patients with:

• Mild controlled hypertension only
• Severe hepatic impairment
• Mild seasonal allergies only
• Stable hypothyroidism only

Correct Answer: Severe hepatic impairment

Q23. Which metabolic pathway primarily handles ethosuximide biotransformation?

• Conjugation with glucuronic acid only
• Hepatic oxidation followed by renal excretion of metabolites
• Direct excretion unchanged in feces
• Metabolism by intestinal bacteria only

Correct Answer: Hepatic oxidation followed by renal excretion of metabolites

Q24. Which of the following drugs is most likely to reduce ethosuximide plasma levels by enzyme induction?

• Rifampicin
• Fluoxetine
• Ciprofloxacin
• Valproic acid

Correct Answer: Rifampicin

Q25. For which clinical scenario is ethosuximide NOT the preferred choice?

• Typical childhood absence seizures as initial monotherapy
• Absence seizures in patients intolerant to valproate
• Status epilepticus requiring urgent IV control
• Long‑term maintenance therapy for typical absences

Correct Answer: Status epilepticus requiring urgent IV control

Q26. Which serious dermatologic reaction has been rarely associated with ethosuximide?

• Psoriasis vulgaris
• Stevens‑Johnson syndrome / toxic epidermal necrolysis
• Alopecia areata as a common effect
• Keratosis pilaris

Correct Answer: Stevens‑Johnson syndrome / toxic epidermal necrolysis

Q27. Ethosuximide’s onset of anticonvulsant effect is generally observed:

• Immediately within seconds of the first dose
• After several days to a few weeks as steady state is achieved
• Only after months of continuous therapy
• Not until the drug is combined with barbiturates

Correct Answer: After several days to a few weeks as steady state is achieved

Q28. Which statement about ethosuximide use in pregnancy is most appropriate?

• Completely safe; no monitoring needed
• Contraindicated in all trimesters without exception
• Use only if potential benefit justifies potential risk to the fetus
• It is a proven folate supplement and recommended

Correct Answer: Use only if potential benefit justifies potential risk to the fetus

Q29. Ethosuximide’s effect on EEG in absence seizures typically includes:

• Suppression of 3 Hz spike‑and‑wave discharges
• Induction of status epilepticus patterns
• Appearance of continuous high‑frequency beta activity
• No change in EEG

Correct Answer: Suppression of 3 Hz spike‑and‑wave discharges

Q30. Which of the following is an appropriate counseling point for patients starting ethosuximide?

• It causes immediate memory improvement
• Avoid abrupt discontinuation; follow gradual dose changes per prescriber
• No interactions with other drugs are expected
• It is safe to drive immediately without monitoring for drowsiness

Correct Answer: Avoid abrupt discontinuation; follow gradual dose changes per prescriber

Q31. Ethosuximide differs from benzodiazepines primarily because it:

• Produces marked anxiolysis at therapeutic doses
• Acts mainly via T‑type calcium channel blockade rather than GABA‑A potentiation
• Is a powerful muscle relaxant
• Is primarily used as a sedative/hypnotic

Correct Answer: Acts mainly via T‑type calcium channel blockade rather than GABA‑A potentiation

Q32. Which adverse effect is particularly relevant to monitor because it may signal serious hematologic toxicity?

• Persistent cough
• Unexplained fever, sore throat or bruising (signs of bone marrow suppression)
• Occasional hiccups
• Intermittent tinnitus

Correct Answer: Unexplained fever, sore throat or bruising (signs of bone marrow suppression)

Q33. Which statement about ethosuximide protein binding is most accurate?

• Extremely high (>95%) protein binding
• Minimal to low protein binding, so interactions via displacement are uncommon
• Protein binding is irrelevant for any drug interactions
• Only binds to albumin irreversibly

Correct Answer: Minimal to low protein binding, so interactions via displacement are uncommon

Q34. Which of the following best describes the excretion of ethosuximide or its metabolites?

• Mostly excreted unchanged in bile
• Metabolites primarily excreted in urine
• Excreted as volatile compounds in breath
• Eliminated exclusively via sweat

Correct Answer: Metabolites primarily excreted in urine

Q35. Which comedication might require ethosuximide dose adjustment due to increased plasma levels?

• Orlistat
• Valproate
• Vitamin C supplements
• Topical corticosteroids

Correct Answer: Valproate

Q36. In terms of seizure spectrum, ethosuximide is least likely to control which of the following?

• Typical absence seizures
• Atypical absence seizures as sole therapy in all cases
• Complex partial seizures (focal impaired awareness)
• Brief generalized nonconvulsive seizures

Correct Answer: Complex partial seizures (focal impaired awareness)

Q37. Which pharmacokinetic property explains the need for several days to reach steady state with ethosuximide?

• Very high oral bioavailability less than 5%
• Rapid renal clearance that fluctuates hourly
• Relatively long elimination half‑life
• Extensive enterohepatic recirculation requiring weeks

Correct Answer: Relatively long elimination half‑life

Q38. Which enzyme system is primarily implicated in metabolism of many antiepileptic drugs including ethosuximide?

• CYP (cytochrome P450) hepatic microsomal enzymes
• Monoamine oxidase only
• Acetylcholinesterase
• Peptidases in plasma

Correct Answer: CYP (cytochrome P450) hepatic microsomal enzymes

Q39. Which clinical sign would be most suggestive of ethosuximide neurotoxicity?

• Progressive hearing loss only
• Severe ataxia, lethargy, and increased somnolence
• Isolated skin dryness
• Improved concentration and alertness

Correct Answer: Severe ataxia, lethargy, and increased somnolence

Q40. For a patient with well‑controlled absence seizures on ethosuximide, which practice is recommended before discontinuation?

• Stop abruptly to prevent withdrawal seizures
• Taper slowly under medical supervision
• Switch to a benzodiazepine immediately without taper
• No need to consult physician; patient can self‑change dose

Correct Answer: Taper slowly under medical supervision

Q41. Which of the following describes an important drug interaction consideration when combining ethosuximide with oral contraceptives?

• Ethosuximide is known to dramatically increase estrogen levels
• Some enzyme inducers can reduce oral contraceptive effectiveness, though ethosuximide has low induction potential
• Ethosuximide always enhances contraceptive efficacy
• No interactions occur with any antiepileptic drugs

Correct Answer: Some enzyme inducers can reduce oral contraceptive effectiveness, though ethosuximide has low induction potential

Q42. Which formulation of ethosuximide is commonly used for pediatric dosing flexibility?

• Injectable solution only
• Oral syrup/suspension
• Transdermal gel
• Rectal suppository

Correct Answer: Oral syrup/suspension

Q43. During ethosuximide therapy, which symptom should prompt immediate medical evaluation?

• Mild transient headache
• Rash with mucosal lesions or fever
• Benign hiccups lasting a few minutes
• Occasional mild nausea with food

Correct Answer: Rash with mucosal lesions or fever

Q44. Which of the following best summarizes the role of ethosuximide in modern epilepsy management?

• First‑line for absence seizures with favorable efficacy and tolerability profile
• First‑line for all seizure types including refractory focal epilepsy
• Obsolete and no longer used clinically
• Primarily an antihypertensive agent

Correct Answer: First‑line for absence seizures with favorable efficacy and tolerability profile

Q45. If a patient on ethosuximide develops unexplained bruising and bleeding, which lab test is most urgent?

• Serum lipid profile
• Complete blood count (CBC) with platelet count
• Thyroid stimulating hormone (TSH)
• Urine pregnancy test only

Correct Answer: Complete blood count (CBC) with platelet count

Q46. Which statement about combining ethosuximide with valproate is correct?

• There are no interactions; they are always safe together
• Valproate may increase ethosuximide levels, requiring monitoring and possible dose adjustment
• Ethosuximide completely prevents valproate adverse effects
• Combination is contra‑indicated in all cases due to fatal outcomes

Correct Answer: Valproate may increase ethosuximide levels, requiring monitoring and possible dose adjustment

Q47. Which pharmacotherapeutic feature makes ethosuximide suitable as first‑line therapy for typical absence seizures in school‑aged children?

• High sedative burden that improves sleep only
• Targeted action on thalamic T‑type calcium channels with good seizure control and relatively favorable cognitive profile
• Significant cognitive enhancement compared with baseline
• Its ability to treat all psychiatric comorbidities

Correct Answer: Targeted action on thalamic T‑type calcium channels with good seizure control and relatively favorable cognitive profile

Q48. Which of the following best describes the chemical feature of succinimide anticonvulsants like ethosuximide?

• They contain a benzodiazepine ring
• They contain a succinimide (pyrrolidine‑2,5‑dione) core structure
• They are steroid derivatives
• They are carbohydrate polymers

Correct Answer: They contain a succinimide (pyrrolidine‑2,5‑dione) core structure

Q49. Which adverse metabolic change can be caused by ethosuximide and should be monitored periodically?

• Marked hyperglycemia in all patients
• Elevated liver transaminases (hepatic enzyme elevations)
• Chronic hypokalemia in most users
• Severe metabolic alkalosis as a common effect

Correct Answer: Elevated liver transaminases (hepatic enzyme elevations)

Q50. Which clinical action is most appropriate if a patient on ethosuximide shows signs of bone marrow suppression?

• Continue drug without change
• Immediately discontinue the drug and perform urgent hematologic evaluation
• Double the dose to overcome suppression
• Switch to an antibiotic to treat suppression

Correct Answer: Immediately discontinue the drug and perform urgent hematologic evaluation

G S Sachin

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