Amobarbital MCQs With Answer

Amobarbital MCQs With Answer provide B.Pharm students a focused, exam-oriented review of amobarbital pharmacology, therapeutic uses, adverse effects, and clinical implications. These targeted MCQs cover mechanism of action, pharmacokinetics, drug interactions, toxicity management, contraindications such as porphyria, and practical dosing considerations to build strong clinical reasoning. Ideal for pharmacology revision, test prep, and quick concept reinforcement, this set emphasizes high-yield facts and deeper understanding of barbiturate pharmacology, metabolism, and safety monitoring. Use these questions to sharpen recall, apply concepts to patient care scenarios, and identify areas needing review. Now let’s test your knowledge with 50 MCQs on this topic.

Q1. Which class of drugs does amobarbital belong to?

• Benzodiazepines
• Barbiturates
• Opioids
• Antihistamines

Correct Answer: Barbiturates

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

• Blocking NMDA receptors
• Inhibiting monoamine oxidase
• Potentiation of GABA-A receptor-mediated chloride influx by increasing channel opening duration
• Agonism at mu-opioid receptors

Correct Answer: Potentiation of GABA-A receptor-mediated chloride influx by increasing channel opening duration

Q3. Amobarbital is best classified by duration of action as which of the following?

• Ultra-short acting
• Short to intermediate acting
• Long acting
• Intravenous-only with no measurable duration

Correct Answer: Short to intermediate acting

Q4. Which pharmacokinetic process primarily eliminates amobarbital from the body?

• Renal excretion of unchanged drug exclusively
• Hepatic metabolism via microsomal enzymes
• Exhalation unchanged through lungs
• Metabolism by intestinal flora only

Correct Answer: Hepatic metabolism via microsomal enzymes

Q5. Which clinical use was historically associated with amobarbital?

• Long-term epilepsy prophylaxis
• Narcoanalysis and short-term sedation prior to procedures
• Chronic pain management
• Antidepressant therapy

Correct Answer: Narcoanalysis and short-term sedation prior to procedures

Q6. Which of the following adverse effects is most clinically significant with amobarbital overdose?

• Hypertension
• Respiratory depression leading to respiratory failure
• Excessive salivation
• Hyperreflexia

Correct Answer: Respiratory depression leading to respiratory failure

Q7. Amobarbital’s effects are likely to be enhanced when taken with which substance?

• Caffeine
• Alcohol
• Vitamin C
• Thyroxine

Correct Answer: Alcohol

Q8. Which clinical condition is a contraindication for barbiturate use including amobarbital?

• Acute intermittent porphyria
• Mild seasonal allergies
• Iron deficiency anemia
• Controlled hypothyroidism

Correct Answer: Acute intermittent porphyria

Q9. Chronic use of amobarbital can lead to which of the following pharmacologic phenomena?

• No tolerance or dependence
• Tolerance, physical dependence, and withdrawal on abrupt cessation
• Immediate tolerance that resolves in hours
• Only psychological dependence without physical signs

Correct Answer: Tolerance, physical dependence, and withdrawal on abrupt cessation

Q10. Which enzyme-related effect is associated with chronic amobarbital therapy?

• Inhibition of CYP450 enzymes
• Induction of hepatic cytochrome P450 enzymes
• No effect on hepatic enzymes
• Inhibition of glucuronyl transferase only

Correct Answer: Induction of hepatic cytochrome P450 enzymes

Q11. Due to enzyme induction by amobarbital, which co-administered drug’s plasma levels are likely to decrease?

• Warfarin
• Insulin (exogenous)
• Digoxin (not extensively metabolized by CYPs)
• Lithium (excreted unchanged by kidneys)

Correct Answer: Warfarin

Q12. Which sign is characteristic of barbiturate withdrawal after chronic use?

• Bradycardia and sedation only
• Anxiety, tremors, insomnia, and possible seizures
• Decreased appetite with weight gain
• Excessive lacrimation without autonomic symptoms

Correct Answer: Anxiety, tremors, insomnia, and possible seizures

Q13. Which route of administration is commonly available for amobarbital formulations?

• Topical only
• Oral and parenteral (IM/IV) formulations
• Inhalational aerosol
• Transdermal patch

Correct Answer: Oral and parenteral (IM/IV) formulations

Q14. Which monitoring parameter is most relevant during prolonged amobarbital therapy?

• Regular complete blood counts only
• Liver function tests due to hepatic enzyme induction and potential toxicity
• Serum amobarbital levels are never useful
• Daily EEG monitoring

Correct Answer: Liver function tests due to hepatic enzyme induction and potential toxicity

Q15. For which of the following indications is phenobarbital preferred over amobarbital?

• Short-term preoperative sedation
• Status epilepticus management (as an anticonvulsant)
• Chronic insomnia with minimal abuse risk
• Opioid withdrawal management

Correct Answer: Status epilepticus management (as an anticonvulsant)

Q16. Which statement about amobarbital’s effect on sleep architecture is true?

• It increases REM sleep proportionally
• It reduces REM sleep and alters normal sleep stages
• It has no impact on sleep stages
• It exclusively increases deep sleep without affecting REM

Correct Answer: It reduces REM sleep and alters normal sleep stages

Q17. Which patient population requires extra caution when prescribing amobarbital due to increased sensitivity?

• Young healthy adults
• Elderly patients and those with respiratory disease
• Patients with controlled hypertension only
• Patients with hyperthyroidism

Correct Answer: Elderly patients and those with respiratory disease

Q18. Which of the following interactions is clinically important with amobarbital?

• Amobarbital reduces the effect of oral contraceptives via enzyme induction
• Amobarbital significantly increases the potency of beta-blockers via CYP inhibition
• Amobarbital neutralizes antacids and reduces GI pH
• Amobarbital increases insulin secretion directly

Correct Answer: Amobarbital reduces the effect of oral contraceptives via enzyme induction

Q19. Which laboratory test can be useful in suspected severe amobarbital poisoning?

• Pulmonary function tests immediately
• Serum drug levels and arterial blood gas for respiratory status
• Fasting lipid profile
• Skin prick allergy testing

Correct Answer: Serum drug levels and arterial blood gas for respiratory status

Q20. Which supportive treatment is central in severe amobarbital overdose?

• Administration of naloxone as the first-line antidote
• Airway management and assisted ventilation
• High-dose benzodiazepines to reverse effects
• Immediate administration of flumazenil

Correct Answer: Airway management and assisted ventilation

Q21. Activated charcoal is indicated in amobarbital poisoning when given within what context?

• Only if the patient is asymptomatic
• Within a limited time after ingestion to reduce absorption, if airway protection is ensured
• Never indicated for barbiturate ingestion
• Only after 48 hours to enhance elimination

Correct Answer: Within a limited time after ingestion to reduce absorption, if airway protection is ensured

Q22. Which statement about cross-tolerance is true for barbiturates like amobarbital?

• There is no cross-tolerance with alcohol or benzodiazepines
• Cross-tolerance exists with other central nervous system depressants such as alcohol and benzodiazepines
• Cross-tolerance only occurs with opioids
• Cross-tolerance prevents all withdrawal symptoms

Correct Answer: Cross-tolerance exists with other central nervous system depressants such as alcohol and benzodiazepines

Q23. Which clinical effect is characteristic of therapeutic doses of amobarbital?

• Stimulation and hyperactivity
• Sedation and anxiolysis
• Profound muscle paralysis without CNS effects
• Increase in seizure frequency

Correct Answer: Sedation and anxiolysis

Q24. Which of the following best describes the acid-base properties relevant to barbiturate elimination?

• Barbiturates are strong bases and are trapped in acidic urine
• Many barbiturates are weak acids and excretion can be enhanced by urinary alkalinization (phenobarbital most notable)
• Barbiturates are neutral and unaffected by urine pH
• Alkalinizing urine decreases barbiturate excretion

Correct Answer: Many barbiturates are weak acids and excretion can be enhanced by urinary alkalinization (phenobarbital most notable)

Q25. Which is a common CNS adverse effect seen with therapeutic use of amobarbital?

• Euphoria without sedation
• Impaired motor coordination and drowsiness
• Enhanced cognitive performance
• Peripheral neuropathy within hours

Correct Answer: Impaired motor coordination and drowsiness

Q26. Which statement about amobarbital and pregnancy is most appropriate?

• It is completely safe in pregnancy and has no fetal effects
• Use during pregnancy may be associated with fetal harm and neonatal withdrawal; caution is advised
• It enhances fetal growth and is recommended for hyperemesis
• It prevents congenital malformations in epileptic mothers

Correct Answer: Use during pregnancy may be associated with fetal harm and neonatal withdrawal; caution is advised

Q27. A patient on chronic amobarbital therapy presents with signs of depression and confusion. Which action is most appropriate?

• Increase the dose to overcome tolerance
• Evaluate for toxicity, consider dose reduction and reassess need for continued therapy
• Switch to a stimulatory medication without evaluation
• Assume symptoms are unrelated and continue the same dose

Correct Answer: Evaluate for toxicity, consider dose reduction and reassess need for continued therapy

Q28. Which of the following drugs would likely have its effect potentiated when co-administered with amobarbital?

• Propranolol (not primarily CNS depressant)
• Diazepam (a benzodiazepine; additive CNS depression)
• Pseudoephedrine (a sympathomimetic stimulant)
• Levothyroxine (thyroid hormone)

Correct Answer: Diazepam (a benzodiazepine; additive CNS depression)

Q29. Which structural feature characterizes barbiturates like amobarbital?

• They are peptide-based molecules
• Derivatives of barbituric acid (pyrimidine dione core)
• Sulfonamide antibiotics
• Monoamine oxidase inhibitor scaffold

Correct Answer: Derivatives of barbituric acid (pyrimidine dione core)

Q30. In the context of drug interactions, amobarbital’s induction of hepatic enzymes commonly affects which pharmacokinetic parameter of other drugs?

• Absorption only
• Increases metabolic clearance leading to reduced plasma concentrations
• Eliminates protein binding
• Stops renal excretion entirely

Correct Answer: Increases metabolic clearance leading to reduced plasma concentrations

Q31. Which clinical scenario increases the risk of severe respiratory depression with amobarbital?

• Concurrent use of selective serotonin reuptake inhibitors (SSRIs)
• Concurrent use of opioids or other CNS depressants
• Use with topical dermatological agents
• Concurrent use of antihistamines only without other depressants

Correct Answer: Concurrent use of opioids or other CNS depressants

Q32. Amobarbital’s role in modern clinical practice is limited primarily because of which reason?

• Lack of any sedative properties
• High potential for abuse, dependence, and safer alternatives (benzodiazepines, Z-drugs)
• Excessively high cost compared to other sedatives
• Inability to be manufactured synthetically

Correct Answer: High potential for abuse, dependence, and safer alternatives (benzodiazepines, Z-drugs)

Q33. Which symptom is least likely to be caused by therapeutic doses of amobarbital?

• Memory impairment
• Respiratory stimulation
• Ataxia
• Dysarthria

Correct Answer: Respiratory stimulation

Q34. Which of the following is an appropriate first step in managing a patient found unresponsive after suspected amobarbital ingestion?

• Give oral activated charcoal immediately without airway assessment
• Ensure airway patency and assess breathing and circulation
• Administer flumazenil to reverse sedative effects
• Perform induced emesis

Correct Answer: Ensure airway patency and assess breathing and circulation

Q35. Which of these best explains why elderly patients are more sensitive to amobarbital?

• Increased hepatic clearance in elderly
• Altered pharmacokinetics (reduced clearance, increased CNS sensitivity) and comorbidities
• Improved renal excretion exclusively
• Resistance to CNS depressant effects

Correct Answer: Altered pharmacokinetics (reduced clearance, increased CNS sensitivity) and comorbidities

Q36. Which of the following best describes the therapeutic index of barbiturates like amobarbital?

• Very wide therapeutic index with no overdose risk
• Narrow therapeutic index, making dosing and monitoring important
• Index that increases with chronic use
• Therapeutic index irrelevant for CNS drugs

Correct Answer: Narrow therapeutic index, making dosing and monitoring important

Q37. A patient on amobarbital therapy plans to start an antibiotic known to inhibit CYP450. What effect is most likely?

• Increased amobarbital plasma concentrations and risk of toxicity
• Decreased amobarbital plasma concentrations
• No change in amobarbital levels due to renal compensation
• Immediate tolerance development

Correct Answer: Increased amobarbital plasma concentrations and risk of toxicity

Q38. Which feature differentiates benzodiazepines from barbiturates like amobarbital in mechanism at the GABA-A receptor?

• Benzodiazepines increase the duration of chloride channel opening while barbiturates increase frequency
• Barbiturates increase the duration of chloride channel opening; benzodiazepines increase the frequency of opening
• Both act as direct GABA agonists at the same site
• Neither interacts with GABA-A receptors

Correct Answer: Barbiturates increase the duration of chloride channel opening; benzodiazepines increase the frequency of opening

Q39. Which clinical test is most helpful to evaluate respiratory compromise from amobarbital?

• Serum amobarbital concentration alone
• Arterial blood gas analysis to assess oxygenation and ventilation
• Urine dipstick for blood
• Serum amylase

Correct Answer: Arterial blood gas analysis to assess oxygenation and ventilation

Q40. In an overdose where prolonged coma is suspected, which elimination-enhancing therapy may be considered for certain barbiturates?

• Forced diuresis with potassium supplements always
• Hemodialysis in severe cases for some barbiturates
• Gastric lavage after 72 hours
• Give high-dose benzodiazepines to increase clearance

Correct Answer: Hemodialysis in severe cases for some barbiturates

Q41. Which of the following is a recognized neuropsychiatric effect of chronic barbiturate use?

• Improved long-term memory
• Depression and cognitive impairment
• Permanent immunity to sedative effects
• Enhanced concentration and alertness

Correct Answer: Depression and cognitive impairment

Q42. Which statement about the interaction between amobarbital and anticoagulants is correct?

• Amobarbital inhibits warfarin metabolism, increasing bleeding risk
• Amobarbital induces enzymes, potentially decreasing warfarin effectiveness and requiring dose adjustment
• There is no interaction between amobarbital and warfarin
• Amobarbital potentiates vitamin K activity directly

Correct Answer: Amobarbital induces enzymes, potentially decreasing warfarin effectiveness and requiring dose adjustment

Q43. Which statement is true about drug dependence liability of barbiturates compared to benzodiazepines?

• Barbiturates generally have lower dependence liability than benzodiazepines
• Barbiturates generally have higher dependence and overdose risk compared to benzodiazepines
• Neither class carries any dependence risk
• Both are identical in dependence liability and safety

Correct Answer: Barbiturates generally have higher dependence and overdose risk compared to benzodiazepines

Q44. Which clinical sign suggests acute barbiturate toxicity rather than simple sedation?

• Mild drowsiness resolving spontaneously
• Marked hypotension accompanied by hypoventilation and slowed reflexes
• Improved alertness after stimulation
• Persistent tachycardia as sole finding

Correct Answer: Marked hypotension accompanied by hypoventilation and slowed reflexes

Q45. Which of the following medications should be avoided or used with caution when combined with amobarbital due to additive CNS depression?

• SSRIs such as sertraline
• Opioids such as morphine
• Thyroid hormone replacement
• Topical antifungals

Correct Answer: Opioids such as morphine

Q46. Which procedure is important before administering activated charcoal to a patient who ingested amobarbital?

• Ensure the patient’s airway is protected or the patient is intubated if necessary
• Check cholesterol levels
• Administer naloxone first
• Perform immediate dialysis

Correct Answer: Ensure the patient’s airway is protected or the patient is intubated if necessary

Q47. Which of the following best describes the cardiovascular effects of high-dose barbiturates like amobarbital?

• Hypertension and tachycardia without CNS depression
• Hypotension due to peripheral vasodilation and possible myocardial depression
• No cardiovascular effects at any dose
• Increased cardiac contractility and blood pressure

Correct Answer: Hypotension due to peripheral vasodilation and possible myocardial depression

Q48. Which factor increases the risk of accumulation and prolonged effect of amobarbital?

• Rapid hepatic metabolism with no induction
• Reduced hepatic function and drug interactions that inhibit metabolism
• Young age with robust metabolism
• Concurrent use of enzyme inducers only

Correct Answer: Reduced hepatic function and drug interactions that inhibit metabolism

Q49. In teaching B.Pharm students about safe prescribing, which principle applies to amobarbital?

• Prefer highest effective dose for longest duration to prevent relapse
• Use the lowest effective dose for the shortest duration, reassess need frequently
• Always combine with alcohol for better effect
• Prescribe freely without counseling about dependence

Correct Answer: Use the lowest effective dose for the shortest duration, reassess need frequently

Q50. Which historical practice involved amobarbital in psychiatric evaluation?

• Electroconvulsive therapy adjunct only
• Narcoanalysis or “truth serum” interviews using barbiturates to lower inhibitions
• Long-term psychodynamic therapy replacement
• Exclusive use as an antidepressant

Correct Answer: Narcoanalysis or “truth serum” interviews using barbiturates to lower inhibitions

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