Pharmacology Quiz: Antipsychotics
20 questions · exam conditions
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AntipsychoticsQuestion 1 of 20

A 22-year-old patient is brought to the emergency department with an involuntary upward deviation of the eyes and twisting of the neck that began two hours after receiving an intramuscular injection of haloperidol. Which pharmacological agent is the most appropriate initial treatment for this condition?

Intramuscular benztropine
Oral propranolol
Intravenous dantrolene
Oral lorazepam
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Pharmacology Quiz

Pharmacology Quiz: Antipsychotics

Practice Antipsychotics in Pharmacology with focused quiz questions that help you check what you know, review explanations, and build confidence with test-style prompts.

What this quiz covers

This quiz focuses on Antipsychotics, giving you a quick way to practice the rules, question types, and explanations that matter most for Pharmacology.

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Try each quiz question before looking at the correct answer. Use the explanations to review missed ideas, then come back to similar questions until the pattern feels familiar.

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Question 1

A 22-year-old patient is brought to the emergency department with an involuntary upward deviation of the eyes and twisting of the neck that began two hours after receiving an intramuscular injection of haloperidol. Which pharmacological agent is the most appropriate initial treatment for this condition?

  1. Intramuscular benztropine (correct answer)
  2. Oral propranolol
  3. Intravenous dantrolene
  4. Oral lorazepam
Explanation: The correct answer is A. The patient is experiencing an acute dystonic reaction, a type of extrapyramidal symptom characterized by sustained muscle contractions. This is a medical emergency that requires prompt treatment with an anticholinergic agent, such as benztropine, or an antihistamine with anticholinergic properties, like diphenhydramine. Propranolol is a first-line treatment for akathisia. Dantrolene is used to treat neuroleptic malignant syndrome. Lorazepam can be an adjunctive treatment but is not the primary intervention for reversing the dystonia.

Question 2

A 30-year-old female patient on a stable dose of a second-generation antipsychotic for schizoaffective disorder complains of amenorrhea and galactorrhea. These symptoms are most likely caused by potent blockade of the tuberoinfundibular dopamine pathway by which agent?

  1. Quetiapine
  2. Aripiprazole
  3. Risperidone (correct answer)
  4. Clozapine
Explanation: The correct answer is C. Dopamine in the tuberoinfundibular pathway normally inhibits prolactin release. Blockade of D2 receptors in this pathway disinhibits prolactin, leading to hyperprolactinemia, which can cause amenorrhea, galactorrhea, and sexual dysfunction. Among the second-generation antipsychotics, risperidone (and its active metabolite, paliperidone) is the most notorious for causing significant hyperprolactinemia due to its potent D2 antagonism. Quetiapine, aripiprazole, and clozapine are considered 'prolactin-sparing' due to weaker or partial agonist D2 activity.

Question 3

A patient taking chlorpromazine complains of persistent dry mouth, constipation, and blurred vision. These side effects are best explained by the drug's antagonist activity at which receptor?

  1. Histamine H1
  2. Alpha-1 adrenergic
  3. Muscarinic M1 (correct answer)
  4. Dopamine D2
Explanation: The correct answer is C. The constellation of dry mouth (decreased salivation), constipation (decreased GI motility), and blurred vision (cycloplegia) is a classic anticholinergic syndrome. These effects are caused by blockade of muscarinic acetylcholine receptors. Low-potency first-generation antipsychotics, like chlorpromazine, have significant M1 antagonist properties. H1 blockade causes sedation and weight gain. Alpha-1 blockade causes orthostatic hypotension. D2 blockade is responsible for the therapeutic effect and EPS.

Question 4

A 68-year-old patient with a 30-year history of schizophrenia treated with various typical antipsychotics presents with persistent, involuntary choreoathetoid movements of the face and tongue. The movements persist despite discontinuation of the offending agent 6 months ago. The underlying pathophysiology of this condition is most closely related to what long-term change in the central nervous system?

  1. Downregulation of nigrostriatal dopamine neurons
  2. Upregulation and supersensitivity of postsynaptic D2 receptors (correct answer)
  3. Enhanced serotonin 5-HT2A receptor antagonism
  4. Chronic blockade of muscarinic M1 receptors
Explanation: The correct answer is B. The patient's presentation is classic for tardive dyskinesia (TD), a delayed-onset movement disorder caused by long-term use of dopamine receptor antagonists. The leading hypothesis for its pathophysiology is that chronic blockade of D2 receptors in the nigrostriatal pathway leads to a compensatory upregulation in the number and sensitivity of these receptors. This renders them 'supersensitive' to dopamine, resulting in the hyperkinetic movements characteristic of TD. Downregulation of dopamine neurons is characteristic of Parkinson's disease. Enhanced 5-HT2A antagonism is thought to be protective against EPS. Chronic M1 blockade is associated with anticholinergic side effects.

Question 5

A physician is choosing a second-generation antipsychotic for a 19-year-old patient with first-episode psychosis. The patient has a strong family history of type 2 diabetes and is overweight (BMI 29). Which pair of antipsychotics represents the highest and lowest risk, respectively, for causing further weight gain and metabolic dysregulation?

  1. Quetiapine (highest); Risperidone (lowest)
  2. Olanzapine (highest); Lurasidone (lowest) (correct answer)
  3. Clozapine (highest); Paliperidone (lowest)
  4. Risperidone (highest); Olanzapine (lowest)
Explanation: The correct answer is B. Second-generation antipsychotics vary widely in their metabolic risk. Olanzapine and clozapine are consistently associated with the highest risk of weight gain, dyslipidemia, and insulin resistance. Lurasidone, ziprasidone, and aripiprazole are considered to have the lowest metabolic risk. Risperidone, paliperidone, and quetiapine fall into an intermediate-risk category. Therefore, the pair with the greatest contrast between highest and lowest risk is olanzapine and lurasidone.

Question 6

A 35-year-old patient with schizophrenia has been stable on olanzapine for two years. At a routine follow-up, their fasting blood glucose is 135 mg/dL and HbA1c is 7.2%. Their BMI has increased from 26 to 33 over the treatment period. Which of the following antipsychotics would be the most appropriate switch to mitigate these metabolic effects while maintaining efficacy?

  1. Clozapine
  2. Quetiapine
  3. Risperidone
  4. Aripiprazole (correct answer)
Explanation: The correct answer is D. The patient is experiencing significant metabolic side effects (new-onset diabetes, weight gain) from olanzapine, which carries one of the highest metabolic risks among second-generation antipsychotics (SGAs). Aripiprazole, along with ziprasidone and lurasidone, is considered to have a much lower risk of metabolic disturbances. Clozapine has a metabolic risk profile similar to or worse than olanzapine. Quetiapine and risperidone carry an intermediate metabolic risk, making them less ideal choices than aripiprazole for a patient who has already developed metabolic syndrome.

Question 7

An elderly patient treated with haloperidol for delirium develops a resting tremor, bradykinesia, and cogwheel rigidity three weeks after initiation of therapy. These symptoms are most likely caused by the drug's antagonist activity at D2 receptors in which dopamine pathway?

  1. Mesolimbic
  2. Mesocortical
  3. Tuberoinfundibular
  4. Nigrostriatal (correct answer)
Explanation: The correct answer is D. The nigrostriatal pathway projects from the substantia nigra to the striatum and is a key component of the basal ganglia motor loop, which regulates voluntary movement. Blockade of D2 receptors in this pathway disrupts normal motor function, leading to drug-induced parkinsonism, characterized by tremor, rigidity, and bradykinesia. The mesolimbic pathway is the primary target for antipsychotic efficacy. The mesocortical pathway is associated with negative and cognitive symptoms of schizophrenia. The tuberoinfundibular pathway regulates prolactin secretion.

Question 8

The lower incidence of extrapyramidal symptoms with second-generation antipsychotics (SGAs) compared to first-generation antipsychotics (FGAs) is a defining feature of their 'atypicality.' Which neurochemical property is thought to be a primary contributor to this improved motor side effect profile?

  1. Potent serotonin 5-HT2A receptor antagonism that exceeds D2 receptor antagonism (correct answer)
  2. Higher affinity for dopamine D1 receptors compared to D2 receptors
  3. Primary action through blockade of glutamate NMDA receptors
  4. Agonist activity at muscarinic acetylcholine receptors
Explanation: The correct answer is A. The 'serotonin-dopamine hypothesis of atypicality' proposes that potent 5-HT2A antagonism is key to the reduced EPS liability of SGAs. Serotonin normally inhibits dopamine release in the nigrostriatal pathway. By blocking 5-HT2A receptors, SGAs disinhibit this pathway, leading to increased dopamine release that can counteract the effects of D2 blockade in the same region, thereby mitigating the risk of EPS. The other options describe mechanisms not characteristic of the SGA class.

Question 9

A 29-year-old patient started on risperidone three weeks ago for bipolar disorder reports an intense inner restlessness and an inability to sit still, constantly pacing in the examination room. The dose of risperidone was recently increased. After ruling out worsening of the underlying psychiatric condition, what is the most appropriate next pharmacological step?

  1. Add benztropine
  2. Add propranolol (correct answer)
  3. Increase the risperidone dose
  4. Switch to intramuscular haloperidol
Explanation: The correct answer is B. The patient is describing akathisia, a common and highly distressing extrapyramidal symptom characterized by subjective and objective restlessness. First-line treatments for akathisia include beta-blockers (like propranolol), benzodiazepines, and mirtazapine. While benztropine is used for other EPS like dystonia and parkinsonism, it is less effective for akathisia. Increasing the risperidone dose or switching to a high-potency typical antipsychotic like haloperidol would likely worsen the akathisia.

Question 10

A new antipsychotic, Drug X, has a receptor binding profile showing high affinity for D2 and 5-HT2A receptors. Its dissociation constant from the D2 receptor is significantly faster than that of haloperidol. It has negligible affinity for H1, M1, and alpha-1 adrenergic receptors. Based on this profile, which statement most accurately predicts its clinical characteristics?

  1. A high risk of metabolic syndrome and weight gain.
  2. A low risk of extrapyramidal symptoms and a low risk of sedation. (correct answer)
  3. Efficacy for positive symptoms but a high risk of acute dystonia.
  4. Significant anticholinergic side effects and hyperprolactinemia.
Explanation: The correct answer is B. The combination of D2 and 5-HT2A antagonism is characteristic of an atypical antipsychotic. The 'fast-off' property from the D2 receptor is associated with a lower risk of extrapyramidal symptoms (EPS) compared to tightly-binding agents like haloperidol. The negligible affinity for H1 receptors predicts a low risk of sedation and weight gain. Negligible M1 affinity predicts a lack of anticholinergic effects. The combination of 5-HT2A antagonism and fast D2 dissociation also mitigates the risk of hyperprolactinemia.

Question 11

A 35-year-old patient with schizophrenia has been stable on olanzapine for two years. At a routine follow-up, their fasting blood glucose is 135 mg/dL and HbA1c is 7.2%. Their BMI has increased from 26 to 33 over the treatment period. Which of the following antipsychotics would be the most appropriate switch to mitigate these metabolic effects while maintaining efficacy?

  1. Clozapine
  2. Quetiapine
  3. Risperidone
  4. Aripiprazole (correct answer)
Explanation: The correct answer is D. The patient is experiencing significant metabolic side effects (new-onset diabetes, weight gain) from olanzapine, which carries one of the highest metabolic risks among second-generation antipsychotics (SGAs). Aripiprazole, along with ziprasidone and lurasidone, is considered to have a much lower risk of metabolic disturbances. Clozapine has a metabolic risk profile similar to or worse than olanzapine. Quetiapine and risperidone carry an intermediate metabolic risk, making them less ideal choices than aripiprazole for a patient who has already developed metabolic syndrome.

Question 12

A new antipsychotic, Drug X, has a receptor binding profile showing high affinity for D2 and 5-HT2A receptors. Its dissociation constant from the D2 receptor is significantly faster than that of haloperidol. It has negligible affinity for H1, M1, and alpha-1 adrenergic receptors. Based on this profile, which statement most accurately predicts its clinical characteristics?

  1. A high risk of metabolic syndrome and weight gain.
  2. A low risk of extrapyramidal symptoms and a low risk of sedation. (correct answer)
  3. Efficacy for positive symptoms but a high risk of acute dystonia.
  4. Significant anticholinergic side effects and hyperprolactinemia.
Explanation: The correct answer is B. The combination of D2 and 5-HT2A antagonism is characteristic of an atypical antipsychotic. The 'fast-off' property from the D2 receptor is associated with a lower risk of extrapyramidal symptoms (EPS) compared to tightly-binding agents like haloperidol. The negligible affinity for H1 receptors predicts a low risk of sedation and weight gain. Negligible M1 affinity predicts a lack of anticholinergic effects. The combination of 5-HT2A antagonism and fast D2 dissociation also mitigates the risk of hyperprolactinemia.

Question 13

A patient with treatment-resistant schizophrenia is being initiated on clozapine. Which monitoring plan is essential and unique to this medication due to its risk of a rare but life-threatening hematological adverse effect?

  1. Biannual electrocardiogram to monitor for QTc prolongation
  2. Quarterly fasting lipid panel and glucose to monitor metabolic changes
  3. Weekly absolute neutrophil count (ANC) for the first 6 months (correct answer)
  4. Monthly liver function tests for the first year to monitor for hepatotoxicity
Explanation: The correct answer is C. Clozapine carries a black box warning for severe neutropenia (agranulocytosis). To mitigate this risk, a strict monitoring protocol via a Risk Evaluation and Mitigation Strategy (REMS) program is mandatory. This involves checking the absolute neutrophil count (ANC) weekly for the first six months, then bi-weekly for the next six months, and monthly thereafter. While monitoring ECGs, metabolic parameters, and LFTs is important with clozapine and other antipsychotics, the stringent, mandatory ANC monitoring is the most critical and unique requirement for this specific drug.

Question 14

A patient stabilized on haloperidol for schizophrenia develops a fever of 40°C (104°F), severe 'lead-pipe' muscle rigidity, altered mental status, and autonomic instability. The patient's psychiatrist recently added fluoxetine for comorbid depression. Which clinical feature is most specific for Neuroleptic Malignant Syndrome (NMS) and helps to differentiate it from serotonin syndrome in this scenario?

  1. Hyperthermia above 40°C (104°F)
  2. Altered mental status ranging from confusion to coma
  3. Severe, diffuse 'lead-pipe' muscle rigidity (correct answer)
  4. Hyperreflexia and myoclonus in the lower extremities
Explanation: The correct answer is C. While hyperthermia and altered mental status are common to both Neuroleptic Malignant Syndrome (NMS) and serotonin syndrome, the quality of the muscle involvement is a key differentiator. NMS is characterized by severe, diffuse, 'lead-pipe' rigidity. In contrast, serotonin syndrome typically presents with neuromuscular excitability, such as hyperreflexia, myoclonus (brief, involuntary muscle jerking), and tremor, not the sustained rigidity seen in NMS.

Question 15

A patient stabilized on haloperidol for schizophrenia develops a fever of 40°C (104°F), severe 'lead-pipe' muscle rigidity, altered mental status, and autonomic instability. The patient's psychiatrist recently added fluoxetine for comorbid depression. Which clinical feature is most specific for Neuroleptic Malignant Syndrome (NMS) and helps to differentiate it from serotonin syndrome in this scenario?

  1. Hyperthermia above 40°C (104°F)
  2. Altered mental status ranging from confusion to coma
  3. Severe, diffuse 'lead-pipe' muscle rigidity (correct answer)
  4. Hyperreflexia and myoclonus in the lower extremities
Explanation: The correct answer is C. While hyperthermia and altered mental status are common to both Neuroleptic Malignant Syndrome (NMS) and serotonin syndrome, the quality of the muscle involvement is a key differentiator. NMS is characterized by severe, diffuse, 'lead-pipe' rigidity. In contrast, serotonin syndrome typically presents with neuromuscular excitability, such as hyperreflexia, myoclonus (brief, involuntary muscle jerking), and tremor, not the sustained rigidity seen in NMS.

Question 16

A 22-year-old patient is brought to the emergency department with an involuntary upward deviation of the eyes and twisting of the neck that began two hours after receiving an intramuscular injection of haloperidol. Which pharmacological agent is the most appropriate initial treatment for this condition?

  1. Intramuscular benztropine (correct answer)
  2. Oral propranolol
  3. Intravenous dantrolene
  4. Oral lorazepam
Explanation: The correct answer is A. The patient is experiencing an acute dystonic reaction, a type of extrapyramidal symptom characterized by sustained muscle contractions. This is a medical emergency that requires prompt treatment with an anticholinergic agent, such as benztropine, or an antihistamine with anticholinergic properties, like diphenhydramine. Propranolol is a first-line treatment for akathisia. Dantrolene is used to treat neuroleptic malignant syndrome. Lorazepam can be an adjunctive treatment but is not the primary intervention for reversing the dystonia.

Question 17

A 45-year-old patient with treatment-resistant schizophrenia is well-stabilized on clozapine 400 mg/day. The patient, a heavy smoker, is admitted to a smoke-free inpatient psychiatric unit. After five days, the patient becomes increasingly sedated, hypotensive, and dizzy. What is the most likely pharmacokinetic explanation for these new symptoms?

  1. Increased induction of CYP1A2, leading to decreased clozapine levels
  2. Decreased induction of CYP1A2, leading to increased clozapine levels (correct answer)
  3. Inhibition of CYP3A4 by hospital diet, leading to increased clozapine levels
  4. Nicotine withdrawal causing direct central nervous system depression
Explanation: The correct answer is B. Polycyclic aromatic hydrocarbons in tobacco smoke are potent inducers of the cytochrome P450 enzyme CYP1A2, which is the primary enzyme responsible for clozapine metabolism. When a patient who smokes heavily is in a smoke-free environment, the induction of CYP1A2 ceases. This leads to a rapid decrease in clozapine metabolism and a subsequent increase in its plasma concentration, potentially to toxic levels, causing sedation, hypotension, and seizures. Nicotine withdrawal typically causes agitation and anxiety, not sedation.

Question 18

A 29-year-old patient started on risperidone three weeks ago for bipolar disorder reports an intense inner restlessness and an inability to sit still, constantly pacing in the examination room. The dose of risperidone was recently increased. After ruling out worsening of the underlying psychiatric condition, what is the most appropriate next pharmacological step?

  1. Add benztropine
  2. Add propranolol (correct answer)
  3. Increase the risperidone dose
  4. Switch to intramuscular haloperidol
Explanation: The correct answer is B. The patient is describing akathisia, a common and highly distressing extrapyramidal symptom characterized by subjective and objective restlessness. First-line treatments for akathisia include beta-blockers (like propranolol), benzodiazepines, and mirtazapine. While benztropine is used for other EPS like dystonia and parkinsonism, it is less effective for akathisia. Increasing the risperidone dose or switching to a high-potency typical antipsychotic like haloperidol would likely worsen the akathisia.

Question 19

A 30-year-old female patient on a stable dose of a second-generation antipsychotic for schizoaffective disorder complains of amenorrhea and galactorrhea. These symptoms are most likely caused by potent blockade of the tuberoinfundibular dopamine pathway by which agent?

  1. Quetiapine
  2. Aripiprazole
  3. Risperidone (correct answer)
  4. Clozapine
Explanation: The correct answer is C. Dopamine in the tuberoinfundibular pathway normally inhibits prolactin release. Blockade of D2 receptors in this pathway disinhibits prolactin, leading to hyperprolactinemia, which can cause amenorrhea, galactorrhea, and sexual dysfunction. Among the second-generation antipsychotics, risperidone (and its active metabolite, paliperidone) is the most notorious for causing significant hyperprolactinemia due to its potent D2 antagonism. Quetiapine, aripiprazole, and clozapine are considered 'prolactin-sparing' due to weaker or partial agonist D2 activity.

Question 20

A patient with treatment-resistant schizophrenia is being initiated on clozapine. Which monitoring plan is essential and unique to this medication due to its risk of a rare but life-threatening hematological adverse effect?

  1. Biannual electrocardiogram to monitor for QTc prolongation
  2. Quarterly fasting lipid panel and glucose to monitor metabolic changes
  3. Weekly absolute neutrophil count (ANC) for the first 6 months (correct answer)
  4. Monthly liver function tests for the first year to monitor for hepatotoxicity
Explanation: The correct answer is C. Clozapine carries a black box warning for severe neutropenia (agranulocytosis). To mitigate this risk, a strict monitoring protocol via a Risk Evaluation and Mitigation Strategy (REMS) program is mandatory. This involves checking the absolute neutrophil count (ANC) weekly for the first six months, then bi-weekly for the next six months, and monthly thereafter. While monitoring ECGs, metabolic parameters, and LFTs is important with clozapine and other antipsychotics, the stringent, mandatory ANC monitoring is the most critical and unique requirement for this specific drug.