Narcotic antagonists – Levallorphan tartrate MCQs With Answer

Introduction

Levallorphan tartrate is an important narcotic antagonist studied in B. Pharm pharmacology modules. As an opioid receptor antagonist with kappa agonist properties, levallorphan reverses μ-receptor–mediated respiratory depression and sedation while potentially causing kappa‑mediated dysphoria. Understanding its pharmacology, mechanism of action, clinical uses as an antidote, formulation as a tartrate salt, adverse effects, and drug interactions is essential for safe medication management. This topic links receptor pharmacodynamics, competitive antagonism, central versus peripheral effects, and the rationale for choosing antagonists in overdose or anesthesia settings. Now let’s test your knowledge with 50 MCQs on this topic.

Q1. What is the primary pharmacological classification of levallorphan?

• A pure μ-opioid receptor agonist
• A μ-opioid receptor antagonist and κ-opioid receptor agonist
• A selective δ-opioid receptor agonist
• A non-opioid analgesic

Correct Answer: A μ-opioid receptor antagonist and κ-opioid receptor agonist

Q2. The term “tartrate” in levallorphan tartrate mainly indicates:

• An additional active opioid agonist
• The salt form to improve water solubility and stability
• A sustained‑release formulation
• A prodrug that is metabolized to levallorphan

Correct Answer: The salt form to improve water solubility and stability

Q3. Levallorphan reverses opioid-induced respiratory depression primarily by antagonizing which receptor?

• κ-opioid receptor
• δ-opioid receptor
• μ-opioid receptor
• Sigma receptor

Correct Answer: μ-opioid receptor

Q4. Which clinical effect is commonly associated with levallorphan due to its κ-opioid agonist activity?

• Euphoria and increased appetite
• Dysphoria and psychotomimetic effects
• Peripheral vasodilation without central effects
• Selective stimulation of respiration without CNS effects

Correct Answer: Dysphoria and psychotomimetic effects

Q5. The antagonism produced by levallorphan at μ receptors is best described as:

• Irreversible noncompetitive antagonism
• Competitive reversible antagonism
• Partial agonism with intrinsic activity
• Allosteric potentiation

Correct Answer: Competitive reversible antagonism

Q6. A major clinical risk when administering levallorphan to an opioid-dependent patient is:

• Precipitation of acute withdrawal symptoms
• Prolonged sedation lasting days
• Development of opioid tolerance
• No observable effect

Correct Answer: Precipitation of acute withdrawal symptoms

Q7. Compared with naloxone, levallorphan is distinctive because it:

• Is a pure μ antagonist with no other receptor activity
• Has κ agonist activity and can produce dysphoria
• Cannot reverse respiratory depression
• Is only used orally due to poor parenteral availability

Correct Answer: Has κ agonist activity and can produce dysphoria

Q8. Which route of administration is commonly used for rapid reversal of opioid effects with levallorphan?

• Topical application
• Intravenous injection
• Transdermal patch
• Buccal lozenge

Correct Answer: Intravenous injection

Q9. In overdose management, a useful property of levallorphan is:

• It enhances opioid analgesia
• It specifically binds only peripheral receptors
• It antagonizes central μ-mediated respiratory depression
• It permanently inactivates opioid receptors

Correct Answer: It antagonizes central μ-mediated respiratory depression

Q10. Which adverse effect is most likely after administration of levallorphan due to central antagonism?

• Constipation worsening
• Dysphoria and anxiety
• Profound bradycardia without other symptoms
• Increased opioid analgesia

Correct Answer: Dysphoria and anxiety

Q11. Levallorphan’s ability to cross the blood–brain barrier results in which outcome?

• Only peripheral reversal of opioid effects
• Central reversal of analgesia and respiratory depression
• No effect on central opioid receptors
• Exclusive action on gastrointestinal μ receptors

Correct Answer: Central reversal of analgesia and respiratory depression

Q12. Which of the following best explains why levallorphan can reverse opioid-induced miosis?

• It stimulates parasympathetic output to the pupil
• It antagonizes μ-opioid receptors centrally
• It blocks adrenergic receptors in the iris
• It acts as a direct muscle relaxant on the iris sphincter

Correct Answer: It antagonizes μ-opioid receptors centrally

Q13. Co-administration of levallorphan with partial opioid agonists (e.g., buprenorphine) may:

• Enhance analgesia synergistically
• Precipitate withdrawal due to receptor antagonism
• Have no pharmacodynamic interaction
• Prevent all opioid side effects without affecting analgesia

Correct Answer: Precipitate withdrawal due to receptor antagonism

Q14. For pharmacology students, levallorphan serves as an example of a drug with:

• Pure agonist activity at all opioid receptors
• Mixed agonist–antagonist properties at different opioid receptors
• Only peripheral nervous system actions
• Anticholinergic and antihistaminic activity

Correct Answer: Mixed agonist–antagonist properties at different opioid receptors

Q15. After intravenous administration, levallorphan’s clinical effects reverse opioid effects because it:

• Irreversibly destroys opioid receptors
• Competes with opioid agonists for receptor binding sites
• Inhibits opioid metabolism thereby increasing agonist levels
• Blocks opioid absorption from the gut

Correct Answer: Competes with opioid agonists for receptor binding sites

Q16. Which monitoring parameter is most essential after giving levallorphan for suspected opioid overdose?

• Blood glucose only
• Respiratory rate and oxygenation
• Serum magnesium concentration
• Intraocular pressure measurement

Correct Answer: Respiratory rate and oxygenation

Q17. One pharmacodynamic difference between levallorphan and peripherally acting opioid antagonists (e.g., methylnaltrexone) is that levallorphan:

• Does not cross the BBB and acts only peripherally
• Crosses the BBB and blocks central opioid effects
• Is a prokinetic agent without receptor actions
• Is selective for gastrointestinal δ receptors

Correct Answer: Crosses the BBB and blocks central opioid effects

Q18. A B. Pharm student should recognize that levallorphan’s onset of action when given IV is typically:

• Rapid, within minutes
• Delayed, several days
• Only after hepatic activation
• Unpredictable and usually weeks

Correct Answer: Rapid, within minutes

Q19. Which clinical scenario is levallorphan most appropriate for?

• As first‑line chronic pain therapy for cancer pain
• Treatment of acute opioid overdose with respiratory depression
• Long-term management of opioid dependence
• Routine prophylactic use to enhance opioid analgesia

Correct Answer: Treatment of acute opioid overdose with respiratory depression

Q20. The primary therapeutic goal when administering levallorphan in overdose is to:

• Increase opioid-induced analgesia
• Restore adequate ventilation and consciousness
• Cause long-term antagonism of all receptors
• Induce peripheral constipation to trap opioids

Correct Answer: Restore adequate ventilation and consciousness

Q21. What is a common gastrointestinal effect after opioid antagonist administration like levallorphan?

• Worsening of opioid-induced constipation by further slowing bowel
• Reversal of opioid-induced bowel hypomotility leading to increased motility
• Complete and permanent paralysis of gut motility
• No effect on gastrointestinal function

Correct Answer: Reversal of opioid-induced bowel hypomotility leading to increased motility

Q22. Which adverse cardiovascular effect may be seen after rapid reversal of opioids with levallorphan?

• Bradycardia and severe hypotension without tachycardia
• Tachycardia and hypertension due to sympathetic surge
• Complete heart block reliably induced
• No cardiovascular effects are possible

Correct Answer: Tachycardia and hypertension due to sympathetic surge

Q23. From a pharmacokinetic perspective, levallorphan is primarily metabolized where?

• In the renal tubules unchanged
• By hepatic metabolism followed by renal excretion of metabolites
• Excreted unchanged in bile only
• Metabolized in the lungs exclusively

Correct Answer: By hepatic metabolism followed by renal excretion of metabolites

Q24. In experimental pharmacology, levallorphan is often used to:

• Activate μ receptors selectively
• Block μ-mediated effects to study non-opioid pathways
• Increase serotonin release in the CNS
• Serve as a dopamine agonist

Correct Answer: Block μ-mediated effects to study non-opioid pathways

Q25. The main reason levallorphan can cause psychotomimetic effects is due to:

• Excessive μ receptor stimulation causing euphoria
• κ-opioid receptor agonism producing dysphoria and perceptual changes
• Its anticholinergic actions in limbic areas
• Direct GABAergic inhibition leading to hallucinations

Correct Answer: κ-opioid receptor agonism producing dysphoria and perceptual changes

Q26. Which statement about levallorphan and naloxone is correct?

• Both are identical in receptor profiles and side effects
• Naloxone is a pure antagonist; levallorphan has mixed antagonist–agonist properties
• Levallorphan has no clinical use while naloxone is always preferred
• Naloxone cannot reverse respiratory depression but levallorphan can

Correct Answer: Naloxone is a pure antagonist; levallorphan has mixed antagonist–agonist properties

Q27. Which patient history is a contraindication or warrants extreme caution before giving levallorphan?

• History of allergy to penicillin
• Known chronic opioid dependence with recent use
• Past history of migraine headaches
• Well‑controlled hypertension on ACE inhibitors

Correct Answer: Known chronic opioid dependence with recent use

Q28. For B. Pharm students, levallorphan exemplifies the concept of:

• Selective enzyme inhibition unrelated to receptors
• Drugs acting as receptor antagonists at one site and agonists at another
• Antibiotic resistance mechanisms
• Pure competitive enzyme activators

Correct Answer: Drugs acting as receptor antagonists at one site and agonists at another

Q29. An expected neurological sign after reversal of opioid overdose with levallorphan is:

• Immediate and sustained loss of consciousness
• Improved level of consciousness and increased respiratory drive
• Rapid development of focal neurological deficits
• Permanent cognitive impairment within minutes

Correct Answer: Improved level of consciousness and increased respiratory drive

Q30. Which laboratory or bedside finding would suggest successful opioid antagonism by levallorphan?

• Persistent miosis and respiratory depression
• Reversal of pinpoint pupils to normal size and improved ventilation
• No change in pupil size but decreased respiratory rate
• Delayed onset of fever with unchanged consciousness

Correct Answer: Reversal of pinpoint pupils to normal size and improved ventilation

Q31. In designing MCQs for pharmacology, a good reason to include levallorphan is to teach:

• Only medicinal chemistry without clinical relevance
• Principles of receptor selectivity, competitive antagonism and clinical antidotes
• How to synthesize tartrate salts in the lab
• How to prescribe antibiotics for community infections

Correct Answer: Principles of receptor selectivity, competitive antagonism and clinical antidotes

Q32. Which effect would NOT be expected after levallorphan administration?

• Reversal of opioid-induced respiratory depression
• Induction of euphoria and enhanced opioid analgesia
• Precipitated opioid withdrawal in dependent patients
• Increased sympathetic activity such as tachycardia

Correct Answer: Induction of euphoria and enhanced opioid analgesia

Q33. In terms of teaching drug interactions, levallorphan interacting with an opioid agonist best illustrates:

• Synergistic potentiation leading to greater analgesia
• Antagonistic pharmacodynamic interaction reducing agonist effects
• Pharmacokinetic inhibition of opioid absorption
• No clinically meaningful interaction

Correct Answer: Antagonistic pharmacodynamic interaction reducing agonist effects

Q34. Which property makes levallorphan less suitable than naloxone for routine use in emergency overdose reversal?

• Predictable lack of central effects
• κ agonist effects producing dysphoria and psychotomimetic symptoms
• Complete inactivity at μ receptors
• Oral-only formulation preventing IV use

Correct Answer: κ agonist effects producing dysphoria and psychotomimetic symptoms

Q35. When teaching formulation, why is it important that levallorphan is provided as a tartrate salt?

• Tartrate salts are universally inactive placebos
• Salt formation often enhances solubility for parenteral use
• It makes the drug a controlled substance with no therapeutic use
• Tartrate converts it into a long‑acting depot injection automatically

Correct Answer: Salt formation often enhances solubility for parenteral use

Q36. Which of the following best describes levallorphan’s role in anesthesia practice historically?

• Used to potentiate opioid effects during surgery
• Used to reverse excessive opioid effects during or after anesthesia
• Commonly used as the primary hypnotic agent
• Used to induce long-term postoperative sedation

Correct Answer: Used to reverse excessive opioid effects during or after anesthesia

Q37. A pharmacology exam question: Levallorphan administration leads to which change in pupil size in opioid-intoxicated patient?

• Pupillary constriction (miosis) worsens
• Pupillary dilation (mydriasis) toward normal size
• No change in pupillary size
• Pupils become fixed and non-reactive permanently

Correct Answer: Pupillary dilation (mydriasis) toward normal size

Q38. Which is a common general adverse effect of opioid antagonists like levallorphan?

• Nodal heart block in all patients
• Nausea and vomiting due to reversal of opioid effects
• Prolonged analgesia lasting weeks
• Permanent renal failure

Correct Answer: Nausea and vomiting due to reversal of opioid effects

Q39. For safe practice, B. Pharm students should remember that after giving an opioid antagonist, patients must be observed because:

• Antagonists permanently remove all opioid receptors
• Some opioids have longer duration and respiratory depression may recur
• No further monitoring is ever required
• Patients will always remain fully sedated

Correct Answer: Some opioids have longer duration and respiratory depression may recur

Q40. Which statement about levallorphan’s effect on opioid analgesia is correct?

• It enhances opioid analgesia while reducing side effects
• It antagonizes opioid analgesia by blocking μ receptors
• It selectively increases peripheral analgesia only
• It has no impact on analgesic efficacy

Correct Answer: It antagonizes opioid analgesia by blocking μ receptors

Q41. Levallorphan is classified chemically as a derivative of which opioid scaffold?

• Benzodiazepine scaffold
• Morphinan (or morphine-like) scaffold
• Barbiturate scaffold
• Tricyclic antidepressant scaffold

Correct Answer: Morphinan (or morphine-like) scaffold

Q42. In pharmacology MCQs, levallorphan helps illustrate which receptor concept?

• All drugs are either strictly agonists or antagonists with no overlap
• Some drugs can show mixed agonist/antagonist activity depending on receptor subtype
• Only peripheral receptors determine all drug effects
• Receptors cannot be competitively inhibited

Correct Answer: Some drugs can show mixed agonist/antagonist activity depending on receptor subtype

Q43. Which of the following is an expected CNS effect after levallorphan administration in a non-dependent opioid-intoxicated patient?

• Improved consciousness and alertness
• Permanent coma despite administration
• Progressive worsening of respiratory depression
• Immediate onset of seizures in all cases

Correct Answer: Improved consciousness and alertness

Q44. Which drug property would most likely account for levallorphan causing central side effects?

• High polarity preventing CNS entry
• Ability to cross the blood–brain barrier
• Exclusive hepatic excretion without CNS distribution
• Strong binding only to gastrointestinal receptors

Correct Answer: Ability to cross the blood–brain barrier

Q45. When teaching about antagonists, levallorphan demonstrates that opioid antagonism is useful to:

• Increase opioid-related respiratory depression intentionally
• Diagnose and treat opioid-induced coma or respiratory failure
• Prolong opioid analgesia for chronic use
• Create opioid dependence in non-users

Correct Answer: Diagnose and treat opioid-induced coma or respiratory failure

Q46. Which physiological response indicates a potentially dangerous reaction after rapid opioid reversal by levallorphan?

• Improved breathing and stable hemodynamics
• Severe agitation, hypertension and tachycardia
• Mild transient warmth and comfort
• Gradual return to baseline without symptoms

Correct Answer: Severe agitation, hypertension and tachycardia

Q47. For a B. Pharm exam, a good pharmacokinetic point about levallorphan is that:

• It is excreted entirely unchanged in feces
• It undergoes hepatic metabolism with renal elimination of metabolites
• It is never metabolized and accumulates indefinitely
• It has no measurable plasma half-life

Correct Answer: It undergoes hepatic metabolism with renal elimination of metabolites

Q48. Which statement about levallorphan’s therapeutic window is most appropriate for students?

• It has an unlimited therapeutic window with no adverse effects
• Its margin is limited by potential for withdrawal and kappa-mediated dysphoria
• It can be given in any dose without monitoring
• Its only adverse effect is local injection site irritation

Correct Answer: Its margin is limited by potential for withdrawal and kappa-mediated dysphoria

Q49. In comparing antagonists, why might naloxone often be preferred over levallorphan in emergencies?

• Naloxone lacks κ agonist dysphoric effects and has a well-established safety profile
• Naloxone causes more severe dysphoria than levallorphan
• Naloxone cannot be given intravenously while levallorphan can
• Naloxone is a prodrug requiring activation making it safer

Correct Answer: Naloxone lacks κ agonist dysphoric effects and has a well-established safety profile

Q50. A final knowledge-check: Which practice is essential after administration of levallorphan for opioid overdose?

• Discharge the patient immediately without observation
• Continue monitoring for recurrent respiratory depression and manage underlying cause
• Avoid supportive measures such as oxygen and airway management
• Give additional opioid agonists to counteract withdrawal

Correct Answer: Continue monitoring for recurrent respiratory depression and manage underlying cause

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