A 37-year-old man with a history of schizophrenia, obesity, anxiety, recurrent pneumonia, and depression is brought to the emergency department. He was recently discharged from inpatient psychiatric care where he was treated for an acute psychotic episode with fluphenazine and started on a new antidepressant. One week after discharge, during a period of cold weather, he is found outdoors confused and poorly dressed. His rectal temperature is 93.2°F (34°C). Which of the following medications is most likely contributing to his hypothermia?
Q162
A 70-year-old male presents to his primary care provider complaining of decreased sexual function. He reports that over the past several years, he has noted a gradual decline in his ability to sustain an erection. He used to wake up with erections but no longer does. His past medical history is notable for diabetes, hyperlipidemia, and a prior myocardial infarction. He takes metformin, glyburide, aspirin, and atorvastatin. He drinks 2-3 drinks per week and has a 25 pack-year smoking history. He has been happily married for 40 years. He retired from his job as a construction worker 5 years ago and has been enjoying retirement with his wife. His physician recommends starting a medication that is also used in the treatment of pulmonary hypertension. Which of the following is a downstream effect of this medication?
Q163
A 32-year-old man presents to his primary care physician because he has been experiencing intermittent episodes of squeezing chest pain and tightness. He says that the pain is 8/10 in severity, radiates to his left arm, and does not appear to be associated with activity. The episodes started 3 months ago and have been occurring about twice per month. His past medical history is significant for migraines for which he takes sumatriptan. Physical exam reveals no abnormalities and an EKG demonstrates sinus tachycardia with no obvious changes. An angiogram is performed to evaluate coronary artery blood flow. During the angiogram, a norepinephrine challenge is administered and blood flow is observed to decrease initially; however, after 2 minutes blood flow is observed to be increased compared to baseline. Which of the following substances is most likely responsible for the increased blood flow observed at this later time point?
Q164
A 14-year-old boy is rushed to the emergency room after he became disoriented at home. His parents say that the boy was doing well until 2 days ago when he got sick and vomited several times. They thought he was recovering but today he appeared to be disoriented since the morning. His vitals are normal except shallow rapid breathing at a rate of 33/min. His blood sugar level is 654 mg/dL and urine is positive for ketone bodies. He is diagnosed with diabetic ketoacidosis and is managed with fluids and insulin. He responds well to the therapy. His parents are told that their son has type 1 diabetes and insulin therapy options are being discussed. Which of the following types of insulin can be used in this patient for the rapid action required during mealtimes?
Q165
A 71-year-old man presents to his oncologist with nausea. He recently underwent chemotherapy for pancreatic cancer and has developed severe intractable nausea over the past week. He vomits several times a day. His past medical history is notable for gout, osteoarthritis, and major depressive disorder. He takes allopurinol and sertraline. He has a 15-pack-year smoking history and drinks 1 glass of wine per day. His temperature is 98.6°F (37°C), blood pressure is 148/88 mmHg, pulse is 106/min, and respirations are 22/min. On exam, he is lethargic but able to answer questions appropriately. He has decreased skin turgor and dry mucous membranes. He is started on a medication to treat nausea. However, 3 days later he presents to the emergency room with fever, agitation, hypertonia, and clonus. What is the most likely mechanism of action of the drug this patient was prescribed?
Q166
A 2-year-old boy is brought to his primary care physician for persistent failure to thrive. He has not been meeting normal motor developmental milestones. Further questioning reveals a family history of congenital kidney disorders, although the parents do not know details. Based on clinical suspicion a panel of lab tests are ordered which reveal a sodium of 129 mg/dL (normal range 136-145), a potassium of 3.1 mg/dL (normal range 3.5-5.0), a bicarbonate of 32 mg/dL (normal range 22-28) and a pH of 7.5 (normal range 7.35-7.45). Urinary calcium excretion is also found to be increased. Which of the following drugs has the most similar mechanism of action to the most likely diagnosis in this patient?
Q167
A 68-year-old man undergoes successful mechanical prosthetic aortic valve replacement for severe aortic valve stenosis. After the procedure, he is started on an oral medication and instructed that he should take for the rest of his life and that he should avoid consuming large amounts of dark-green, leafy vegetables. Which of the following laboratory parameters should be regularly monitored to guide dosing of this drug?
Q168
A 50-year-old man with a history of atrial fibrillation presents to his cardiologist’s office for a follow-up visit. He recently started treatment with an anti-arrhythmic drug to prevent future recurrences and reports that he has been feeling well and has no complaints. The physical examination shows that the arrhythmia appears to have resolved; however, there is now mild bradycardia. In addition, the electrocardiogram recording shows a slight prolongation of the PR and QT intervals. Which of the following drugs was most likely used to treat this patient?
Q169
A 30-year-old male presents to a local clinic with a complaint of a stiff neck. The patient is known to be sporadic with follow-up appointments but was last seen recently for a regular depot injection. He initially presented with complaints of paranoid delusions and auditory hallucinations that lasted for 7 months and caused significant social and financial deterioration. He was brought into the clinic by his older brother, who provides social support. Because of the patient's tendency to be non-compliant with medications, the patient was placed on a specific drug to mitigate this pattern. Which of the following medications is responsible for the patient's movement disorder?
Q170
A 28-year-old woman with a history of migraines presents to your office due to sudden loss of vision in her left eye and difficulty speaking. Two weeks ago she experienced muscle aches, fever, and cough. Her muscle aches are improving but she continues to have a cough. She also feels as though she has been more tired than usual. She had a similar episode of vision loss 2 years ago and had an MRI at that time. She has a family history of migraines and takes propranolol daily. On swinging light test there is decreased constriction of the left pupil relative to the right pupil. You repeat the MRI and note enhancing lesions in the left optic nerve. Which of the following is used to prevent progression of this condition?
Autonomic/CV Drugs US Medical PG Practice Questions and MCQs
Question 161: A 37-year-old man with a history of schizophrenia, obesity, anxiety, recurrent pneumonia, and depression is brought to the emergency department. He was recently discharged from inpatient psychiatric care where he was treated for an acute psychotic episode with fluphenazine and started on a new antidepressant. One week after discharge, during a period of cold weather, he is found outdoors confused and poorly dressed. His rectal temperature is 93.2°F (34°C). Which of the following medications is most likely contributing to his hypothermia?
A. Fluphenazine (Correct Answer)
B. Valproic acid
C. Diphenhydramine
D. Fluoxetine
E. Lithium
Explanation: **Fluphenazine**
- **First-generation antipsychotics** like fluphenazine can impair the body's ability to **thermoregulate** by interfering with dopaminergic pathways in the hypothalamus, increasing susceptibility to hypothermia in cold environments.
- Given the patient's recent discharge from inpatient care and exposure to cold weather while poorly dressed, the addition of an antipsychotic affecting thermoregulation strongly contributes to his hypothermia.
*Valproic acid*
- Valproic acid is an **anticonvulsant** and **mood stabilizer** primarily used for bipolar disorder and epilepsy.
- While it can have various side effects, **hypothermia** is not a commonly reported or significant side effect of valproic acid.
*Diphenhydramine*
- Diphenhydramine is an **antihistamine** with significant **sedative** and **anticholinergic** properties.
- While it can cause sedation and anticholinergic effects that might impact a patient's awareness or ability to seek shelter, it is not directly implicated in causing hypothermia through thermoregulatory dysfunction.
*Fluoxetine*
- Fluoxetine is a **selective serotonin reuptake inhibitor (SSRI)** commonly used for depression and anxiety.
- While SSRIs can have various side effects, **hypothermia** is not a characteristic or significant side effect of fluoxetine.
*Lithium*
- Lithium is a **mood stabilizer** used primarily for bipolar disorder.
- **Hypothyroidism** is a known side effect of long-term lithium use, which could theoretically contribute to an inability to maintain body temperature, but it is less likely to cause acute hypothermia compared to antipsychotics directly affecting thermoregulation.
Question 162: A 70-year-old male presents to his primary care provider complaining of decreased sexual function. He reports that over the past several years, he has noted a gradual decline in his ability to sustain an erection. He used to wake up with erections but no longer does. His past medical history is notable for diabetes, hyperlipidemia, and a prior myocardial infarction. He takes metformin, glyburide, aspirin, and atorvastatin. He drinks 2-3 drinks per week and has a 25 pack-year smoking history. He has been happily married for 40 years. He retired from his job as a construction worker 5 years ago and has been enjoying retirement with his wife. His physician recommends starting a medication that is also used in the treatment of pulmonary hypertension. Which of the following is a downstream effect of this medication?
A. Increase cGMP degradation
B. Increase cAMP production
C. Increase PDE5 activity
D. Decrease nitric oxide production
E. Decrease cGMP degradation (Correct Answer)
Explanation: ***Decrease cGMP degradation***
- The medication described is likely a **phosphodiesterase-5 (PDE5) inhibitor** (e.g., sildenafil, tadalafil), used for erectile dysfunction and pulmonary hypertension.
- These drugs work by inhibiting the enzyme PDE5, which is responsible for the breakdown of **cyclic GMP (cGMP)**, thereby increasing cGMP levels.
*Increase cGMP degradation*
- This is the **opposite** of the medication's intended effect, as it would lead to reduced cGMP levels and worsen erectile dysfunction.
- An increase in cGMP degradation would diminish the **vasodilatory** effects necessary for erection.
*Increase cAMP production*
- This medication primarily affects the **cGMP pathway**, not directly boosting cyclic AMP (cAMP) production.
- While cAMP also plays a role in vasodilation, it's regulated by different enzymes and pathways, such as **adenylyl cyclase**.
*Increase PDE5 activity*
- This would lead to a more **rapid breakdown of cGMP**, counteracting the goal of the medication and exacerbating erectile dysfunction.
- The medication's mechanism is specifically designed to **inhibit PDE5 activity**.
*Decrease nitric oxide production*
- **Nitric oxide (NO)** production is a **precursor** to cGMP synthesis, as NO activates guanylate cyclase to produce cGMP.
- Decreasing NO production would **reduce cGMP levels**, which is contrary to the action of PDE5 inhibitors.
Question 163: A 32-year-old man presents to his primary care physician because he has been experiencing intermittent episodes of squeezing chest pain and tightness. He says that the pain is 8/10 in severity, radiates to his left arm, and does not appear to be associated with activity. The episodes started 3 months ago and have been occurring about twice per month. His past medical history is significant for migraines for which he takes sumatriptan. Physical exam reveals no abnormalities and an EKG demonstrates sinus tachycardia with no obvious changes. An angiogram is performed to evaluate coronary artery blood flow. During the angiogram, a norepinephrine challenge is administered and blood flow is observed to decrease initially; however, after 2 minutes blood flow is observed to be increased compared to baseline. Which of the following substances is most likely responsible for the increased blood flow observed at this later time point?
A. Angiotensin
B. Thromboxane A2
C. Epinephrine
D. Adenosine (Correct Answer)
E. Histamine
Explanation: ***Adenosine***
- The patient's symptoms (squeezing chest pain, radiation to the left arm, not activity-related, intermittent) are consistent with **vasospastic angina** (Prinzmetal's angina). The brief decrease in blood flow followed by an increase after a norepinephrine challenge suggests initial vasoconstriction followed by compensatory vasodilation.
- **Adenosine** is a potent **endogenous vasodilator** in the coronary arteries. It is released by myocardial cells during periods of increased metabolic demand or hypoxia and also as a compensatory mechanism following vasoconstrictive challenges. Its release leads to an increase in blood flow to meet metabolic needs.
*Angiotensin*
- **Angiotensin II** is a potent **vasoconstrictor**, acting primarily through the AT1 receptor.
- It would further reduce blood flow, not increase it, especially following a norepinephrine challenge.
*Thromboxane A2*
- **Thromboxane A2** is a potent **vasoconstrictor** and platelet aggregator.
- Its primary role is to promote clotting and reduce blood flow, which would not explain the observed increase in flow.
*Epinephrine*
- **Epinephrine** has complex effects on vasculature depending on receptor distribution; however, at therapeutic concentrations, it generally causes **vasoconstriction** via alpha-1 adrenergic receptors in coronary arteries, especially when exogenous norepinephrine is already present.
- While it can cause vasodilation via beta-2 receptors in some vascular beds, its net effect in this scenario would likely be vasoconstrictive or maintain constriction, not promote increased flow.
*Histamine*
- **Histamine** can cause vasodilation via H1 and H2 receptors, but its primary role is in **inflammatory and allergic responses**.
- While it can cause increased blood flow, it is not typically the primary physiological compensatory mechanism for reversing vasoconstriction in the coronary arteries following a norepinephrine challenge in the context of angina.
Question 164: A 14-year-old boy is rushed to the emergency room after he became disoriented at home. His parents say that the boy was doing well until 2 days ago when he got sick and vomited several times. They thought he was recovering but today he appeared to be disoriented since the morning. His vitals are normal except shallow rapid breathing at a rate of 33/min. His blood sugar level is 654 mg/dL and urine is positive for ketone bodies. He is diagnosed with diabetic ketoacidosis and is managed with fluids and insulin. He responds well to the therapy. His parents are told that their son has type 1 diabetes and insulin therapy options are being discussed. Which of the following types of insulin can be used in this patient for the rapid action required during mealtimes?
A. Insulin detemir
B. Insulin degludec
C. NPH insulin
D. Insulin glargine
E. Insulin lispro (Correct Answer)
Explanation: ***Insulin lispro***
- **Insulin lispro** is a **rapid-acting insulin analog** designed to be taken immediately before or with a meal, offering quick onset (5-15 minutes) and short duration of action.
- Its rapid action helps to control **postprandial glucose spikes**, closely mimicking the physiological insulin response to food, which is crucial for mealtime coverage in **Type 1 diabetes**.
*Insulin detemir*
- **Insulin detemir** is a **long-acting insulin analog** used for basal insulin coverage, providing a relatively constant insulin level over an extended period (12-24 hours).
- It is not suitable for **mealtime insulin coverage** due to its slow onset of action and prolonged duration, which would not effectively manage postprandial glucose excursions.
*Insulin degludec*
- **Insulin degludec** is an **ultra-long-acting basal insulin analog** with a duration of action exceeding 42 hours, providing stable basal coverage.
- Its extremely slow onset and prolonged duration make it unsuitable for **prandial (mealtime) insulin**, as it cannot address the rapid rise in blood glucose following a meal.
*NPH insulin*
- **NPH (Neutral Protamine Hagedorn) insulin** is an **intermediate-acting insulin** that provides basal insulin coverage, with an onset of 2-4 hours and a peak effect around 6-10 hours.
- Its slow onset and prolonged action make it unsuitable for **mealtime insulin coverage**, as it would not adequately prevent the rapid rise in blood sugar immediately after eating.
*Insulin glargine*
- **Insulin glargine** is a **long-acting insulin analog** used for **basal insulin coverage**, providing a relatively flat and peakless insulin profile over 24 hours.
- It is not used for **prandial (mealtime) insulin** because its slow onset and sustained action would not effectively counteract the rapid rise in blood glucose following a meal.
Question 165: A 71-year-old man presents to his oncologist with nausea. He recently underwent chemotherapy for pancreatic cancer and has developed severe intractable nausea over the past week. He vomits several times a day. His past medical history is notable for gout, osteoarthritis, and major depressive disorder. He takes allopurinol and sertraline. He has a 15-pack-year smoking history and drinks 1 glass of wine per day. His temperature is 98.6°F (37°C), blood pressure is 148/88 mmHg, pulse is 106/min, and respirations are 22/min. On exam, he is lethargic but able to answer questions appropriately. He has decreased skin turgor and dry mucous membranes. He is started on a medication to treat nausea. However, 3 days later he presents to the emergency room with fever, agitation, hypertonia, and clonus. What is the most likely mechanism of action of the drug this patient was prescribed?
A. 5-HT3 receptor antagonist (Correct Answer)
B. M1 receptor antagonist
C. Opiate receptor agonist
D. D2 receptor antagonist
E. H1 receptor antagonist
Explanation: ***5-HT3 receptor antagonist***
- The patient's symptoms of **fever**, **agitation**, **hypertonia**, and **clonus** after starting an antiemetic strongly suggest **serotonin syndrome**.
- **Ondansetron**, a common 5-HT3 receptor antagonist used for chemotherapy-induced nausea, can precipitate serotonin syndrome, especially when used with **SSRIs** like **sertraline**.
*M1 receptor antagonist*
- **M1 receptor antagonists** (e.g., scopolamine, atropine) are anticholinergic agents that can cause dry mouth, blurred vision, urinary retention, and constipation.
- They are not typically associated with the severe neuromuscular and autonomic hyperactivity seen in **serotonin syndrome**.
*Opiate receptor agonist*
- **Opiate receptor agonists** (e.g., morphine, fentanyl) primarily cause CNS depression, respiratory depression, constipation, and miosis.
- They do not cause features like clonus, agitation, or hypertonia characteristic of **serotonin syndrome**.
*D2 receptor antagonist*
- **D2 receptor antagonists** (e.g., metoclopramide, prochlorperazine) can cause **extrapyramidal symptoms** (dystonia, akathisia) and **neuroleptic malignant syndrome** (NMS).
- NMS also presents with fever and rigidity but lacks hyperreflexia and clonus, which are prominent in **serotonin syndrome**.
*H1 receptor antagonist*
- **H1 receptor antagonists** (e.g., promethazine, diphenhydramine) are used for nausea due to their sedative and anticholinergic effects.
- Their side effects include sedation, dizziness, and anticholinergic effects, but not the specific constellation of symptoms indicative of **serotonin syndrome**.
Question 166: A 2-year-old boy is brought to his primary care physician for persistent failure to thrive. He has not been meeting normal motor developmental milestones. Further questioning reveals a family history of congenital kidney disorders, although the parents do not know details. Based on clinical suspicion a panel of lab tests are ordered which reveal a sodium of 129 mg/dL (normal range 136-145), a potassium of 3.1 mg/dL (normal range 3.5-5.0), a bicarbonate of 32 mg/dL (normal range 22-28) and a pH of 7.5 (normal range 7.35-7.45). Urinary calcium excretion is also found to be increased. Which of the following drugs has the most similar mechanism of action to the most likely diagnosis in this patient?
A. Hydrochlorothiazide
B. Furosemide (Correct Answer)
C. Spironolactone
D. Amiloride
E. Acetazolamide
Explanation: **Furosemide**
- The patient's presentation with **failure to thrive**, **motor developmental delay**, **hypokalemia**, **metabolic alkalosis**, and **hypercalciuria** is highly suggestive of **Bartter syndrome**. This condition is caused by a genetic defect in the **Na-K-2Cl cotransporter (NKCC2)** in the **thick ascending limb of the loop of Henle**.
- **Furosemide** is a loop diuretic that works by inhibiting the **NKCC2 cotransporter**, thus mimicking the physiological effects seen in Bartter syndrome.
*Hydrochlorothiazide*
- This drug inhibits the **Na-Cl cotransporter** in the **distal convoluted tubule**, which is a different segment of the nephron and has a distinct mechanism of action from the defect in Bartter syndrome.
- While it can cause hypokalemia, it typically causes **hypocalciuria**, which is opposite to the hypercalciuria seen in this patient.
*Spironolactone*
- This is an **aldosterone antagonist** that acts in the **collecting duct** to inhibit sodium reabsorption and potassium excretion.
- Its primary mechanism of action is far removed from the defect in the thick ascending limb of the loop of Henle characteristic of Bartter syndrome.
*Amiloride*
- This is a **potassium-sparing diuretic** that directly inhibits **epithelial sodium channels (ENaC)** in the collecting duct.
- This mechanism is unrelated to the Na-K-2Cl cotransporter defect found in Bartter syndrome.
*Acetazolamide*
- This drug is a **carbonic anhydrase inhibitor** that acts primarily in the **proximal tubule** to inhibit bicarbonate reabsorption.
- It causes a **metabolic acidosis**, which is the opposite of the metabolic alkalosis seen in this patient.
Question 167: A 68-year-old man undergoes successful mechanical prosthetic aortic valve replacement for severe aortic valve stenosis. After the procedure, he is started on an oral medication and instructed that he should take for the rest of his life and that he should avoid consuming large amounts of dark-green, leafy vegetables. Which of the following laboratory parameters should be regularly monitored to guide dosing of this drug?
A. D-dimer
B. Anti-factor Xa activity
C. Activated partial thromboplastin time
D. Prothrombin time (Correct Answer)
E. Thrombin time
Explanation: ***Prothrombin time***
- **Warfarin** is the standard chronic anticoagulant post-mechanical valve replacement, and its dosing is monitored using the **prothrombin time (PT)**, reported as the **International Normalized Ratio (INR)**.
- The avoidance of dark-green, leafy vegetables indicates a **Vitamin K antagonist**, which is warfarin.
*D-dimer*
- **D-dimer** levels are primarily used to rule out **venous thromboembolism (VTE)** and are not used for routine monitoring of chronic anticoagulation.
- Elevated D-dimer indicates recent or ongoing **fibrinolysis**, which is not directly targeted by warfarin therapy.
*Anti-factor Xa activity*
- **Anti-factor Xa activity** is used to monitor the anticoagulant effect of **low molecular weight heparins (LMWH)** or **direct oral anticoagulants (DOACs)** like rivaroxaban or apixaban.
- This patient is on a vitamin K antagonist, not an anti-Xa inhibitor.
*Activated partial thromboplastin time*
- The **activated partial thromboplastin time (aPTT)** is used to monitor patients receiving **unfractionated heparin**, not warfarin.
- While both heparin and warfarin are anticoagulants, they act on different parts of the coagulation cascade and are monitored differently.
*Thrombin time*
- **Thrombin time (TT)** measures the time it takes for plasma to clot after adding thrombin, and it is primarily used to detect inherited or acquired **fibrinogen disorders** or to monitor **direct thrombin inhibitors**.
- It is not routinely used for monitoring warfarin therapy.
Question 168: A 50-year-old man with a history of atrial fibrillation presents to his cardiologist’s office for a follow-up visit. He recently started treatment with an anti-arrhythmic drug to prevent future recurrences and reports that he has been feeling well and has no complaints. The physical examination shows that the arrhythmia appears to have resolved; however, there is now mild bradycardia. In addition, the electrocardiogram recording shows a slight prolongation of the PR and QT intervals. Which of the following drugs was most likely used to treat this patient?
A. Metoprolol
B. Sotalol (Correct Answer)
C. Propranolol
D. Verapamil
E. Carvedilol
Explanation: ***Sotalol***
- **Sotalol** is a **beta-blocker** and a **Class III antiarrhythmic** drug, meaning it blocks potassium channels.
- This dual action explains the **bradycardia** (beta-blockade) and the **prolongation of the PR and QT intervals** (potassium channel blockade), which are characteristic side effects.
*Metoprolol*
- **Metoprolol** is a **selective beta-1 blocker** (Class II antiarrhythmic) that would cause **bradycardia** and **PR prolongation**, but it does not typically prolong the **QT interval**.
- It primarily affects the heart rate and AV nodal conduction without significant potassium channel blocking properties.
*Propranolol*
- **Propranolol** is a **non-selective beta-blocker** (Class II antiarrhythmic) that would cause **bradycardia** and **PR prolongation**.
- Similar to metoprolol, it does not typically prolong the **QT interval**.
*Verapamil*
- **Verapamil** is a **non-dihydropyridine calcium channel blocker** (Class IV antiarrhythmic) that causes **bradycardia** and **PR prolongation**.
- However, it does not prolong the **QT interval**; instead, it can sometimes shorten it.
*Carvedilol*
- **Carvedilol** is a **non-selective beta-blocker** with **alpha-1 blocking properties** (Class II antiarrhythmic), leading to **bradycardia** and **PR prolongation**.
- It does not have effects on potassium channels that would lead to **QT prolongation**.
Question 169: A 30-year-old male presents to a local clinic with a complaint of a stiff neck. The patient is known to be sporadic with follow-up appointments but was last seen recently for a regular depot injection. He initially presented with complaints of paranoid delusions and auditory hallucinations that lasted for 7 months and caused significant social and financial deterioration. He was brought into the clinic by his older brother, who provides social support. Because of the patient's tendency to be non-compliant with medications, the patient was placed on a specific drug to mitigate this pattern. Which of the following medications is responsible for the patient's movement disorder?
A. Thioridazine
B. Clozapine
C. Haloperidol (Correct Answer)
D. Olanzapine
E. Benztropine
Explanation: ***Haloperidol***
- The patient's history of **paranoid delusions** and **auditory hallucinations** lasting 7 months, along with significant social and financial deterioration, is consistent with **schizophrenia**.
- Given the patient's **non-compliance** and lack of social support, he was likely prescribed a **long-acting injectable antipsychotic**. **Haloperidol decanoate** is a first-generation antipsychotic often used in this scenario, known for its higher risk of **extrapyramidal symptoms (EPS)** like a **stiff neck (dystonia)** compared to second-generation agents.
*Thioridazine*
- **Thioridazine** is a **first-generation antipsychotic** but is associated with a **lower incidence of EPS** compared to other high-potency typical antipsychotics like haloperidol.
- It also carries significant risks of **cardiac arrhythmias (QT prolongation)** and **retinal toxicity**, making it a less common choice for long-term management, especially with compliance issues.
*Clozapine*
- **Clozapine** is an atypical (second-generation) antipsychotic known for its efficacy in **treatment-resistant schizophrenia** and a very **low risk of EPS**.
- However, it requires **weekly blood monitoring** due to the risk of **agranulocytosis**, which makes it unsuitable for a patient with compliance issues and lack of social support.
*Olanzapine*
- **Olanzapine** is a **second-generation antipsychotic** that is available as a **long-acting injection**. While it can cause some EPS, the risk is generally **lower than with haloperidol**.
- It is more commonly associated with **metabolic side effects** such as weight gain, hyperglycemia, and dyslipidemia, rather than severe acute dystonia as the primary concern.
*Benztropine*
- **Benztropine** is an **anticholinergic medication** used to **treat the EPS induced by antipsychotics**, such as dystonia and parkinsonism.
- If a patient is experiencing a stiff neck due to an antipsychotic, benztropine would be a treatment for the side effect, not the cause of it.
Question 170: A 28-year-old woman with a history of migraines presents to your office due to sudden loss of vision in her left eye and difficulty speaking. Two weeks ago she experienced muscle aches, fever, and cough. Her muscle aches are improving but she continues to have a cough. She also feels as though she has been more tired than usual. She had a similar episode of vision loss 2 years ago and had an MRI at that time. She has a family history of migraines and takes propranolol daily. On swinging light test there is decreased constriction of the left pupil relative to the right pupil. You repeat the MRI and note enhancing lesions in the left optic nerve. Which of the following is used to prevent progression of this condition?
A. Dexamethasone
B. Infliximab
C. Methotrexate
D. Adalimumab
E. Natalizumab (Correct Answer)
Explanation: ***Natalizumab***
- This patient's presentation with recurrent optic neuritis, fatigue, and enhancing lesions on MRI, combined with a history of similar episodes, strongly suggests **multiple sclerosis (MS)**. Natalizumab is a **monoclonal antibody** that blocks the migration of lymphocytes across the blood-brain barrier, effectively preventing disease progression in MS.
- It is a **highly effective disease-modifying therapy** for relapsing-remitting MS (RRMS) and is often used in patients who have failed other first-line treatments due to its efficacy in reducing relapse rates and preventing new lesions.
*Dexamethasone*
- While **corticosteroids** like dexamethasone are used to treat **acute exacerbations** or relapses in MS by reducing inflammation, they do not prevent long-term disease progression.
- Its primary role is to **shorten the duration and severity of an acute attack**, rather than to modify the underlying disease course.
*Infliximab*
- Infliximab is an **anti-TNF-α biologic agent** primarily used in the treatment of **inflammatory bowel disease** (Crohn's disease, ulcerative colitis), rheumatoid arthritis, and other autoimmune conditions.
- It is **contraindicated in MS** as it has been shown to worsen the disease and even induce demyelination in some patients.
*Methotrexate*
- Methotrexate is an **immunosuppressant** and **chemotherapeutic agent** used in conditions like rheumatoid arthritis, psoriasis, and certain cancers.
- It is **not a primary treatment for MS** and has limited to no role in preventing its progression.
*Adalimumab*
- Adalimumab is another **anti-TNF-α agent** similar to infliximab, used for conditions such as rheumatoid arthritis, psoriatic arthritis, and inflammatory bowel disease.
- Like infliximab, **TNF-α blockers are generally avoided in MS** due to concerns about exacerbating the disease.