LEHNE PHARM OPIOID ANALGESICS &
ANTAGONISTS REVISION/PRACTICE EXAM 100+
QUESTIONS AND ANSWERS WITH RATIONALES |A+
GUARANTEED 2026-2027 UPDATE*
1. The primary receptor responsible for opioid analgesia is:
A) Delta receptor
B) Kappa receptor
C) Mu receptor
D) Sigma receptor
Rationale: μ (mu) receptors mediate most analgesic effects of opioids
including euphoria and respiratory depression.
2. Morphine is classified as:
A) Partial agonist
B) Full opioid agonist
C) Antagonist
D) Mixed agonist-antagonist
Rationale: Morphine is a full agonist at μ-receptors producing strong
analgesia.
3. The most dangerous acute adverse effect of opioids is:
A) Constipation
B) Nausea
C) Respiratory depression
D) Miosis
Rationale: Opioids depress brainstem respiratory centers leading to
potentially fatal hypoventilation.
4. Naloxone is best described as:
A) Partial agonist
, B) Mixed agonist
C) Pure opioid antagonist
D) Weak agonist
Rationale: Naloxone competitively blocks opioid receptors with no agonist
activity.
5. Naloxone has:
A) Long half-life
B) Short duration of action
C) No CNS effect
D) Oral bioavailability
Rationale: It acts rapidly but is short-acting, requiring repeat dosing in
overdose.
6. Which drug is used for opioid dependence maintenance therapy?
A) Morphine
B) Fentanyl
C) Methadone
D) Codeine
Rationale: Methadone is a long-acting opioid used in substitution therapy.
7. Buprenorphine is:
A) Full agonist
B) Partial agonist
C) Antagonist only
D) NSAID
Rationale: It is a partial μ-agonist with ceiling effect on respiratory
depression.
8. Opioid-induced constipation is due to:
A) CNS stimulation
B) Decreased GI motility
C) Increased secretion
D) Increased peristalsis
Rationale: μ-receptor activation reduces intestinal motility.
, 9. Which opioid is most potent?
A) Morphine
B) Codeine
C) Tramadol
D) Fentanyl
Rationale: Fentanyl is highly lipophilic and extremely potent.
10.Tramadol acts by:
A) Pure μ agonism
B) Weak μ agonism + serotonin/norepinephrine reuptake inhibition
C) Antagonism
D) NSAID mechanism
Rationale: It has dual opioid and monoaminergic activity.
11.Which opioid is safest in renal failure?
A) Morphine
B) Codeine
C) Fentanyl
D) Meperidine
Rationale: Fentanyl has no active toxic metabolites.
12.Morphine causes histamine release leading to:
A) Hypertension
B) Hypotension and itching
C) Hyperthermia
D) Tachycardia
Rationale: Histamine release causes vasodilation.
13.Which is a mixed agonist-antagonist?
A) Morphine
B) Pentazocine
C) Fentanyl
D) Methadone
Rationale: Pentazocine acts on κ receptors and blocks μ receptors.
ANTAGONISTS REVISION/PRACTICE EXAM 100+
QUESTIONS AND ANSWERS WITH RATIONALES |A+
GUARANTEED 2026-2027 UPDATE*
1. The primary receptor responsible for opioid analgesia is:
A) Delta receptor
B) Kappa receptor
C) Mu receptor
D) Sigma receptor
Rationale: μ (mu) receptors mediate most analgesic effects of opioids
including euphoria and respiratory depression.
2. Morphine is classified as:
A) Partial agonist
B) Full opioid agonist
C) Antagonist
D) Mixed agonist-antagonist
Rationale: Morphine is a full agonist at μ-receptors producing strong
analgesia.
3. The most dangerous acute adverse effect of opioids is:
A) Constipation
B) Nausea
C) Respiratory depression
D) Miosis
Rationale: Opioids depress brainstem respiratory centers leading to
potentially fatal hypoventilation.
4. Naloxone is best described as:
A) Partial agonist
, B) Mixed agonist
C) Pure opioid antagonist
D) Weak agonist
Rationale: Naloxone competitively blocks opioid receptors with no agonist
activity.
5. Naloxone has:
A) Long half-life
B) Short duration of action
C) No CNS effect
D) Oral bioavailability
Rationale: It acts rapidly but is short-acting, requiring repeat dosing in
overdose.
6. Which drug is used for opioid dependence maintenance therapy?
A) Morphine
B) Fentanyl
C) Methadone
D) Codeine
Rationale: Methadone is a long-acting opioid used in substitution therapy.
7. Buprenorphine is:
A) Full agonist
B) Partial agonist
C) Antagonist only
D) NSAID
Rationale: It is a partial μ-agonist with ceiling effect on respiratory
depression.
8. Opioid-induced constipation is due to:
A) CNS stimulation
B) Decreased GI motility
C) Increased secretion
D) Increased peristalsis
Rationale: μ-receptor activation reduces intestinal motility.
, 9. Which opioid is most potent?
A) Morphine
B) Codeine
C) Tramadol
D) Fentanyl
Rationale: Fentanyl is highly lipophilic and extremely potent.
10.Tramadol acts by:
A) Pure μ agonism
B) Weak μ agonism + serotonin/norepinephrine reuptake inhibition
C) Antagonism
D) NSAID mechanism
Rationale: It has dual opioid and monoaminergic activity.
11.Which opioid is safest in renal failure?
A) Morphine
B) Codeine
C) Fentanyl
D) Meperidine
Rationale: Fentanyl has no active toxic metabolites.
12.Morphine causes histamine release leading to:
A) Hypertension
B) Hypotension and itching
C) Hyperthermia
D) Tachycardia
Rationale: Histamine release causes vasodilation.
13.Which is a mixed agonist-antagonist?
A) Morphine
B) Pentazocine
C) Fentanyl
D) Methadone
Rationale: Pentazocine acts on κ receptors and blocks μ receptors.
