Oxazolidine diones – Trimethadione MCQs With Answer

Oxazolidine diones – Trimethadione MCQs With Answer

Oxazolidine diones, notably trimethadione, are an older class of anticonvulsants with distinct chemistry and clinical significance for absence seizures. This concise, student-focused introduction covers trimethadione’s chemical structure, mechanism of action, pharmacokinetics, active metabolite (dimethadione), major adverse effects including teratogenicity and blood dyscrasias, and the need for therapeutic monitoring. B. Pharm students will benefit from targeted review of drug interactions, contraindications, and safety monitoring that inform rational clinical use and patient counselling. Clear, exam-style practice enhances retention and prepares you for professional assessments. Now let’s test your knowledge with 50 MCQs on this topic.

Q1. Which chemical class does trimethadione belong to?

• Hydantoin derivative
• Oxazolidine dione
• Benzodiazepine
• Barbiturate

Correct Answer: Oxazolidine dione

Q2. What is the primary clinical use of trimethadione historically?

• Generalized tonic-clonic seizures
• Absence (petit mal) seizures
• Myoclonic seizures
• Parkinson’s disease tremor

Correct Answer: Absence (petit mal) seizures

Q3. Which of the following best describes the core ring structure in trimethadione?

• Six-membered lactam ring
• Five-membered oxazolidine-2,4-dione ring
• Imidazole ring
• Thiophene ring

Correct Answer: Five-membered oxazolidine-2,4-dione ring

Q4. Trimethadione’s anticonvulsant effect is primarily through modulation of which ionic current?

• Voltage-gated sodium currents
• NMDA receptor-mediated currents
• T-type calcium currents in thalamic neurons
• Potassium inward rectifier currents

Correct Answer: T-type calcium currents in thalamic neurons

Q5. Which active metabolite of trimethadione is associated with prolonged effects and toxicity?

• Phenytoin
• Dimethadione
• Phenobarbital
• Carbamazepine epoxide

Correct Answer: Dimethadione

Q6. One of the most serious teratogenic consequences of maternal trimethadione exposure is known as:

• Fetal warfarin syndrome
• Fetal trimethadione syndrome
• Neonatal abstinence syndrome
• Turner syndrome

Correct Answer: Fetal trimethadione syndrome

Q7. Which characteristic feature is commonly associated with fetal trimethadione syndrome?

• Microcephaly and facial dysmorphism
• Excessive birth weight
• Polydactyly only
• Isolated renal agenesis

Correct Answer: Microcephaly and facial dysmorphism

Q8. Which routine laboratory tests are most important to monitor in a patient receiving trimethadione?

• Blood glucose and thyroid function
• Liver function tests and complete blood count
• Serum amylase and lipase
• Serum cortisol and ACTH

Correct Answer: Liver function tests and complete blood count

Q9. Which adverse effect is particularly associated with trimethadione and dimethadione accumulation?

• Neurotoxicity with ataxia and cognitive impairment
• Hyperthyroidism
• Pulmonary fibrosis
• Osteomalacia

Correct Answer: Neurotoxicity with ataxia and cognitive impairment

Q10. Trimethadione is least likely to be chosen as first-line therapy today because of:

• Superior efficacy compared to other agents
• Fewer adverse effects than newer drugs
• High teratogenicity and serious adverse effects
• Low cost and easy availability

Correct Answer: High teratogenicity and serious adverse effects

Q11. Which monitoring is recommended due to trimethadione’s ocular side effects?

• Regular ophthalmologic examinations
• Monthly vision tests by phone
• No ocular monitoring required
• Annual retinal surgery prophylaxis

Correct Answer: Regular ophthalmologic examinations

Q12. What type of blood dyscrasia can be caused by trimethadione?

• Polycythemia vera
• Agranulocytosis and neutropenia
• Hemophilia A
• Essential thrombocythemia

Correct Answer: Agranulocytosis and neutropenia

Q13. The chemical name of trimethadione reflects how many methyl substituents on the ring?

• One methyl group
• Two methyl groups
• Three methyl groups
• No methyl groups

Correct Answer: Three methyl groups

Q14. Which metabolic organ primarily handles trimethadione biotransformation?

• Liver
• Kidney
• Lungs
• Skin

Correct Answer: Liver

Q15. Trimethadione’s use is contraindicated in which population because of risk to the fetus?

• Pediatric male patients
• Pregnant women
• Patients with hypertension only
• Patients with hyperlipidemia only

Correct Answer: Pregnant women

Q16. How does dimethadione relate to trimethadione clinically?

• Dimethadione is an inert impurity
• Dimethadione is an active metabolite with longer persistence and toxicity
• Dimethadione is an antagonist that reverses trimethadione
• Dimethadione is a co-administered supportive drug

Correct Answer: Dimethadione is an active metabolite with longer persistence and toxicity

Q17. Which adverse effect should be emphasized during patient counselling for trimethadione therapy?

• Immediate improvement of vision
• Potential for sedation, cognitive slowing and vision problems
• Guaranteed weight loss
• Permanent immunity to seizures with one dose

Correct Answer: Potential for sedation, cognitive slowing and vision problems

Q18. Compared with ethosuximide, trimethadione is generally:

• Less teratogenic and preferred in pregnancy
• More toxic with a higher teratogenic risk
• Identical in safety profile
• An anticonvulsant for tonic-clonic seizures only

Correct Answer: More toxic with a higher teratogenic risk

Q19. Which symptom is an early sign of trimethadione toxicity?

• Improved concentration
• Nystagmus and ataxia
• Increased appetite
• Hyperactivity

Correct Answer: Nystagmus and ataxia

Q20. Which pharmacokinetic property explains prolonged adverse effects after stopping trimethadione?

• Rapid renal clearance of parent drug
• Formation of long‑lived metabolite dimethadione
• Absence of metabolism
• Immediate neutralization in plasma

Correct Answer: Formation of long‑lived metabolite dimethadione

Q21. Which of the following is a key counseling point about contraception for women of childbearing potential on trimethadione?

• No special precautions are needed
• Use effective contraception due to high teratogenic risk
• Trimethadione enhances contraceptive efficacy
• Only barrier methods are contraindicated

Correct Answer: Use effective contraception due to high teratogenic risk

Q22. Which hepatic enzyme system is most likely involved in trimethadione metabolism?

• CYP450 enzyme system
• Monoamine oxidase only
• Alcohol dehydrogenase exclusively
• Salivary amylase

Correct Answer: CYP450 enzyme system

Q23. In toxicology, which organ system is primarily assessed when dimethadione levels are elevated?

• Hematologic and neurologic systems
• Gastrointestinal flora
• Skeletal muscles exclusively
• Hair and nails

Correct Answer: Hematologic and neurologic systems

Q24. Which of the following is NOT a typical adverse effect of trimethadione?

• Teratogenicity
• Blood dyscrasias
• Severe hypoglycemia as a direct effect
• Ocular disturbances

Correct Answer: Severe hypoglycemia as a direct effect

Q25. Which structural feature gives oxazolidine diones their “dione” designation?

• Presence of two hydroxyl groups
• Presence of two carbonyl (C=O) groups on the ring
• Presence of a single sulfur atom
• Multiple aromatic rings

Correct Answer: Presence of two carbonyl (C=O) groups on the ring

Q26. For which reason might trimethadione therapy require periodic complete blood counts?

• To monitor for hyperkalemia
• To detect blood dyscrasias such as neutropenia
• To measure plasma drug concentration precisely
• To assess coagulation factor levels

Correct Answer: To detect blood dyscrasias such as neutropenia

Q27. Which statement about trimethadione formulation and administration is correct?

• It is only available as an intravenous injection
• It has been available as oral tablets historically
• It must be administered via inhalation
• It is a topical cream

Correct Answer: It has been available as oral tablets historically

Q28. Which modern anticonvulsant has largely replaced trimethadione for absence seizures due to improved safety?

• Ethosuximide
• Lithium
• Warfarin
• Isotretinoin

Correct Answer: Ethosuximide

Q29. Which pharmacovigilance advice is important for patients taking trimethadione?

• Ignore any new rash or fever
• Report signs of infection, unexplained bruising, or vision changes promptly
• Stop monitoring after one month
• Double the dose if seizures persist

Correct Answer: Report signs of infection, unexplained bruising, or vision changes promptly

Q30. Which of the following best describes trimethadione’s status in modern pharmacotherapy?

• First-line and widely used due to safety
• Rarely used today and reserved for refractory cases due to toxicity
• Used as a dietary supplement
• Indicated for hypertension management

Correct Answer: Rarely used today and reserved for refractory cases due to toxicity

Q31. Which cognitive adverse effect can be associated with chronic trimethadione treatment?

• Enhanced memory formation
• Cognitive slowing and attention deficits
• Improved executive function
• Increased IQ

Correct Answer: Cognitive slowing and attention deficits

Q32. Which of the following interactions should be anticipated with trimethadione?

• No interactions with any other CNS depressants
• Potential additive CNS depression with other sedatives
• Complete inactivation by vitamin C
• It potentiates insulin action exclusively

Correct Answer: Potential additive CNS depression with other sedatives

Q33. Which precaution is essential before starting trimethadione in women?

• Confirm pregnancy due to teratogenic risk
• No need to assess pregnancy status
• Only men require pregnancy tests
• Start without counselling on contraception

Correct Answer: Confirm pregnancy due to teratogenic risk

Q34. Which animal or human outcome contributed to the historical decline in trimethadione use?

• Reports of exceptional fetal outcomes
• High rates of congenital malformations and developmental delay
• Universal tolerance with no adverse events
• Increased fertility in exposed populations

Correct Answer: High rates of congenital malformations and developmental delay

Q35. Which clinical feature differentiates absence seizures from other seizure types that trimethadione treats?

• Prolonged tonic-clonic convulsions
• Brief lapses of consciousness with 3 Hz spike-and-wave EEG pattern
• Focal sensory deficits lasting days
• Chronic progressive dementia only

Correct Answer: Brief lapses of consciousness with 3 Hz spike-and-wave EEG pattern

Q36. Which toxicologic effect is directly associated with dimethadione accumulation in neonates?

• Transient neonatal hyperactivity
• Prolonged neonatal toxicity and developmental problems
• Immediate neonatal immunity
• Rapid neonatal weight gain

Correct Answer: Prolonged neonatal toxicity and developmental problems

Q37. Which structural description of trimethadione is accurate?

• A peptide-derived cyclopeptide
• 3,5,5-trimethyl-oxazolidine-2,4-dione derivative
• A steroid nucleus with four fused rings
• A polysaccharide chain

Correct Answer: 3,5,5-trimethyl-oxazolidine-2,4-dione derivative

Q38. Which teratogenic counseling statement is correct for trimethadione?

• It is safe in the first trimester only
• It poses high risk throughout pregnancy and should be avoided if possible
• It causes no fetal harm and needs no counseling
• It enhances fetal neurologic development

Correct Answer: It poses high risk throughout pregnancy and should be avoided if possible

Q39. Which adverse hepatic effect may be seen with trimethadione therapy?

• Hepatotoxicity with elevated transaminases
• Immediate liver regeneration
• Guaranteed protection from hepatitis
• Exclusive gallbladder enlargement without liver injury

Correct Answer: Hepatotoxicity with elevated transaminases

Q40. Which monitoring frequency is reasonable for LFTs when initiating trimethadione therapy?

• No monitoring ever needed
• Baseline and periodic monitoring during treatment
• Hourly monitoring indefinitely
• Only monitor after 10 years

Correct Answer: Baseline and periodic monitoring during treatment

Q41. Which regulatory or practical point applies to trimethadione use today?

• Widely promoted as over-the-counter therapy
• Often restricted or rarely used given safer alternatives
• Used primarily as an antibiotic
• Available as a daily vitamin supplement

Correct Answer: Often restricted or rarely used given safer alternatives

Q42. Which counseling point about driving and operating machinery is most appropriate for patients on trimethadione?

• It improves alertness; no restrictions
• Advise caution because sedation and cognitive impairment may occur
• Driving is strictly encouraged during treatment
• No effect on psychomotor skills

Correct Answer: Advise caution because sedation and cognitive impairment may occur

Q43. Which adverse endocrine effect has been reported in association with some anticonvulsants but is not a classic feature of trimethadione?

• Hypothyroidism linked to enzyme induction (not classic for trimethadione)
• Immediate improvement in fertility
• Marked hyperinsulinemia as defining toxicity
• Exclusive androgen deficiency only with trimethadione

Correct Answer: Hypothyroidism linked to enzyme induction (not classic for trimethadione)

Q44. Which statement about therapeutic drug monitoring for trimethadione is accurate?

• Serum level measurement is never useful
• Monitoring may help correlate levels with toxicity due to narrow therapeutic margin
• Drug levels are irrelevant because toxicity is unpredictable only
• Monitoring cures fetal defects

Correct Answer: Monitoring may help correlate levels with toxicity due to narrow therapeutic margin

Q45. Which adverse dermatologic reaction can occur with anticonvulsants and requires immediate attention?

• Benign tanning
• Severe rash or Stevens-Johnson syndrome
• Guaranteed acne improvement
• No skin reactions at all

Correct Answer: Severe rash or Stevens-Johnson syndrome

Q46. Which specialist referral may be appropriate for a patient on trimethadione with vision changes?

• Dermatologist
• Ophthalmologist
• Orthopedist
• Podiatrist

Correct Answer: Ophthalmologist

Q47. Which feature in a newborn would prompt consideration of in utero exposure to trimethadione?

• Post-term macrosomia only
• Congenital anomalies including microcephaly and facial dysmorphism
• Complete absence of congenital issues
• Isolated transient jaundice only

Correct Answer: Congenital anomalies including microcephaly and facial dysmorphism

Q48. Which adverse psychiatric effect can be associated with anticonvulsant toxicity including trimethadione?

• Mania exclusively and nothing else
• Depression, confusion and behavioral changes
• Instantaneous personality enhancement
• Only euphoria with no other effects

Correct Answer: Depression, confusion and behavioral changes

Q49. Which is the best academic approach for a B. Pharm student studying trimethadione pharmacology?

• Memorize only brand names
• Understand chemistry, mechanism, PK/PD, adverse effects and monitoring
• Ignore mechanism and focus on advertisements
• Only study unrelated drug classes

Correct Answer: Understand chemistry, mechanism, PK/PD, adverse effects and monitoring

Q50. Which long-term management strategy is most responsible when a patient on trimethadione develops neutropenia?

• Continue drug and wait indefinitely
• Discontinue trimethadione and manage neutropenia with appropriate care
• Increase dose of trimethadione
• Ignore and stop monitoring

Correct Answer: Discontinue trimethadione and manage neutropenia with appropriate care

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