A 62-year-old man comes to the physician for an annual health maintenance examination. He has a history of stable angina, gout, and hypertension. His medications include lisinopril and aspirin. He has smoked a pack of cigarettes daily for 20 years. He drinks 5–6 beers on the weekends. His blood pressure is 150/85 mm Hg. Laboratory studies show a total cholesterol of 276 mg/dL with an elevated low-density lipoprotein (LDL) concentration and low high-density lipoprotein (HDL) concentration. Administration of which of the following agents is the most appropriate next step in management?
Q142
A 58-year-old chronic smoker known to have chronic bronchitis for the last 20 years presents to his physician for a scheduled follow-up visit. He mentions that over the last month he has been having difficulty breathing, especially after climbing stairs. He also says that he has had similar episodes in the past, which were relieved with the use of inhaled bronchodilators, but recently the breathlessness has ceased to respond to them. He also mentions frequent pain in the right upper quadrant of the abdomen. On physical examination, his temperature is 37°C (98.6°F), the pulse is 96/min, the blood pressure is 124/82 mm Hg, and the respirations are 26/min. Auscultation of the chest reveals wheezing bilaterally and a loud pulmonic component of the second heart sound. Two-dimensional echocardiography shows a dilated right ventricle with increased wall thickness. Right heart catheterization is performed, which indicates a pulmonary artery pressure of 30 mm Hg and a pulmonary capillary wedge pressure of 13 mm Hg. There is a significant drop in pulmonary artery pressure after the administration of inhaled nitric oxide. In addition to continued appropriate management of chronic bronchitis, which of the following medications is most likely to improve symptoms in the patient?
Q143
A 55-year-old woman presents to the emergency department with chest pain, shortness of breath, and weakness. She has no known past medical history and generally refuses to see a physician for health issues. Review of systems is notable for chronic, severe gastroesophageal reflux disease and chronic diarrhea. Her temperature is 98.3°F (36.8°C), blood pressure is 177/105 mmHg, pulse is 88/min, respirations are 14/min, and oxygen saturation is 97% on room air. Laboratory values are ordered as seen below.
Hemoglobin: 10 g/dL
Hematocrit: 30%
Leukocyte count: 4,500/mm^3 with normal differential
Platelet count: 192,400/mm^3
Serum:
Na+: 139 mEq/L
Cl-: 101 mEq/L
K+: 6.3 mEq/L
BUN: 65 mg/dL
Glucose: 99 mg/dL
Creatinine: 3.1 mg/dL
Notably, the patient requires nursing to help her with most tasks such as putting on her gown and manipulating a cup of water given poor mobility of her hands. She also has recurrent episodes of severe hand pain, which self resolve. The patient is given calcium, insulin, and dextrose and started on dialysis. Which of the following is the most appropriate medical therapy for this patient?
Q144
A 71-year-old African American man diagnosed with high blood pressure presents to the outpatient clinic. In the clinic, his blood pressure is 161/88 mm Hg with a pulse of 88/min. He has had similar blood pressure measurements in the past, and you initiate captopril. He presents back shortly after initiation with extremely swollen lips, tongue, and face. After captopril is discontinued, what is the most appropriate step for the management of his high blood pressure?
Q145
A 50-year-old woman presents with a severe headache and vomiting. She says that symptoms onset after attending a wine tasting at the local winery. She says that her headache is mostly at the back of her head and that she has been nauseous and vomited twice. Past medical history is significant for depression diagnosed 20 years ago but now well-controlled with medication. She also has significant vitamin D deficiency. Current medications are phenelzine and a vitamin D supplement. The patient denies any smoking history, alcohol or recreational drug use. On physical examination, the patient is diaphoretic. Her pupils are dilated. Which of the following is most likely to be elevated in this patient?
Q146
A 52-year-old man comes to the physician for a routine health maintenance examination. He feels well. His blood pressure is 125/70 mm Hg. His glomerular filtration rate is calculated to be 105 mL/min/1.73 m2 and glucose clearance is calculated to be 103 mL/min. This patient is most likely being treated with which of the following agents?
Q147
A 57-year-old man comes to the physician because of sudden-onset fever, malaise, and pain and swelling of his wrists and ankles that began a week ago. One month ago, he was started on hydralazine for adjunctive treatment of hypertension. His temperature is 37.8°C (100°F). Examination shows swelling, tenderness, warmth, and erythema of both wrists and ankles; range of motion is limited. Further evaluation is most likely to show an increased level of which of the following autoantibodies?
Q148
A simple experiment is performed to measure the breakdown of sucrose into glucose and fructose by a gut enzyme that catalyzes this reaction. A glucose meter is used to follow the breakdown of sucrose into glucose. When no enzyme is added to the sucrose solution, the glucose meter will have a reading of 0 mg/dL; but when the enzyme is added, the glucose meter will start to show readings indicative of glucose being formed. Which of the following diabetic pharmacological agents, when added before the addition of the gut enzyme to the sucrose solution, will maintain a reading of 0 mg/dL?
Q149
A patient presents with periods of severe headaches and flushing however every time they have come to the physician they have not experienced any symptoms. The only abnormal finding is a blood pressure of 175 mmHg/100 mmHg. It is determined that the optimal treatment for this patient is surgical. Prior to surgery which of the following noncompetitive inhibitors should be administered?
Q150
A physician is choosing whether to prescribe losartan or lisinopril to treat hypertension in a 56-year-old male. Relative to losartan, one would expect treatment with lisinopril to produce which of the following changes in the circulating levels of these peptides?
Antihypertensives US Medical PG Practice Questions and MCQs
Question 141: A 62-year-old man comes to the physician for an annual health maintenance examination. He has a history of stable angina, gout, and hypertension. His medications include lisinopril and aspirin. He has smoked a pack of cigarettes daily for 20 years. He drinks 5–6 beers on the weekends. His blood pressure is 150/85 mm Hg. Laboratory studies show a total cholesterol of 276 mg/dL with an elevated low-density lipoprotein (LDL) concentration and low high-density lipoprotein (HDL) concentration. Administration of which of the following agents is the most appropriate next step in management?
A. Peroxisome proliferator-activated receptor alpha activator
B. Cholesterol absorption inhibitor
C. HMG-CoA reductase inhibitor (Correct Answer)
D. Bile acid resin
E. Proprotein convertase subtilisin kexin 9 inhibitor
Explanation: ***HMG-CoA reductase inhibitor***
- This patient has a history of **stable angina**, **hypertension**, and **dyslipidemia** (elevated LDL, low HDL), placing him at high risk for cardiovascular events. **Statins** (HMG-CoA reductase inhibitors) are first-line therapy for reducing LDL cholesterol and cardiovascular risk in such patients.
- They work by **inhibiting the rate-limiting step of cholesterol synthesis** in the liver, leading to an upregulation of LDL receptors and increased clearance of LDL from the blood.
*Peroxisome proliferator-activated receptor alpha activator*
- These agents, like **fibrates**, primarily reduce **triglycerides** and can increase HDL, but they are less effective at lowering LDL compared to statins.
- They are typically used for patients with **severe hypertriglyceridemia** or in combination with statins if significant HDL or triglyceride issues persist.
*Cholesterol absorption inhibitor*
- **Ezetimibe** works by preventing the absorption of cholesterol in the small intestine.
- While effective at lowering LDL, it is generally used as an **add-on therapy to statins** or for patients unable to tolerate statins, rather than as a first-line agent in high-risk patients.
*Bile acid resin*
- **Bile acid sequestrants** (e.g., cholestyramine) work by binding bile acids in the intestine, preventing their reabsorption and increasing their excretion.
- This leads to increased hepatic synthesis of bile acids from cholesterol, lowering LDL, but they can cause **gastrointestinal side effects** and are generally less potent and less tolerated than statins.
*Proprotein convertase subtilisin kexin 9 inhibitor*
- **PCSK9 inhibitors** are highly effective at lowering LDL cholesterol by preventing the degradation of LDL receptors, thereby increasing LDL clearance.
- They are typically reserved for patients with **familial hypercholesterolemia** or those with established cardiovascular disease who have not achieved adequate LDL lowering with maximally tolerated statin therapy, often due to their high cost and subcutaneous administration.
Question 142: A 58-year-old chronic smoker known to have chronic bronchitis for the last 20 years presents to his physician for a scheduled follow-up visit. He mentions that over the last month he has been having difficulty breathing, especially after climbing stairs. He also says that he has had similar episodes in the past, which were relieved with the use of inhaled bronchodilators, but recently the breathlessness has ceased to respond to them. He also mentions frequent pain in the right upper quadrant of the abdomen. On physical examination, his temperature is 37°C (98.6°F), the pulse is 96/min, the blood pressure is 124/82 mm Hg, and the respirations are 26/min. Auscultation of the chest reveals wheezing bilaterally and a loud pulmonic component of the second heart sound. Two-dimensional echocardiography shows a dilated right ventricle with increased wall thickness. Right heart catheterization is performed, which indicates a pulmonary artery pressure of 30 mm Hg and a pulmonary capillary wedge pressure of 13 mm Hg. There is a significant drop in pulmonary artery pressure after the administration of inhaled nitric oxide. In addition to continued appropriate management of chronic bronchitis, which of the following medications is most likely to improve symptoms in the patient?
A. Captopril
B. Hydralazine
C. Diltiazem (Correct Answer)
D. Losartan
E. Isosorbide mononitrate
Explanation: ***Diltiazem***
- This patient presents with **pulmonary hypertension** secondary to chronic obstructive pulmonary disease (COPD) along with **vasoreactivity** (indicated by the response to inhaled nitric oxide).
- **Calcium channel blockers** like diltiazem are effective in vasoreactive pulmonary hypertension by causing pulmonary vasodilation, reducing pulmonary artery pressure, and improving right ventricular function.
*Captopril*
- **Angiotensin-converting enzyme (ACE) inhibitors** primarily act as systemic vasodilators and are used in systemic hypertension and heart failure.
- They are **not indicated** for the primary treatment of pulmonary hypertension and do not target the underlying pulmonary vascular remodeling or vasoreactivity.
*Hydralazine*
- **Direct arterial vasodilators** like hydralazine primarily reduce systemic vascular resistance and are used in systemic hypertension.
- They are **not typically used** in pulmonary hypertension as their effects on the pulmonary vasculature are less specific and beneficial compared to other agents.
*Losartan*
- **Angiotensin receptor blockers (ARBs)**, like ACE inhibitors, are primarily used for systemic hypertension and heart failure.
- They have **no significant role** in the treatment of pulmonary hypertension, especially in the context of vasoreactivity.
*Isosorbide mononitrate*
- **Nitrates** are primarily venodilators and are used in coronary artery disease to reduce preload and in some cases of heart failure.
- While they can have some pulmonary vasodilatory effect, they are **not the primary treatment** for pulmonary hypertension, particularly in vasoreactive cases, and their benefit is less pronounced compared to calcium channel blockers.
Question 143: A 55-year-old woman presents to the emergency department with chest pain, shortness of breath, and weakness. She has no known past medical history and generally refuses to see a physician for health issues. Review of systems is notable for chronic, severe gastroesophageal reflux disease and chronic diarrhea. Her temperature is 98.3°F (36.8°C), blood pressure is 177/105 mmHg, pulse is 88/min, respirations are 14/min, and oxygen saturation is 97% on room air. Laboratory values are ordered as seen below.
Hemoglobin: 10 g/dL
Hematocrit: 30%
Leukocyte count: 4,500/mm^3 with normal differential
Platelet count: 192,400/mm^3
Serum:
Na+: 139 mEq/L
Cl-: 101 mEq/L
K+: 6.3 mEq/L
BUN: 65 mg/dL
Glucose: 99 mg/dL
Creatinine: 3.1 mg/dL
Notably, the patient requires nursing to help her with most tasks such as putting on her gown and manipulating a cup of water given poor mobility of her hands. She also has recurrent episodes of severe hand pain, which self resolve. The patient is given calcium, insulin, and dextrose and started on dialysis. Which of the following is the most appropriate medical therapy for this patient?
A. Labetalol
B. Nifedipine
C. Furosemide
D. Hydrochlorothiazide
E. Captopril (Correct Answer)
Explanation: ***Captopril***
* Given the patient's presentation with **scleroderma renal crisis** (hypertension, elevated creatinine, and new-onset anemia), an **ACE inhibitor** like captopril is the **first-line treatment** for blood pressure control and prevention of further renal damage.
* **ACE inhibitors** are crucial for managing the severe hypertension and are the only class of antihypertensive agents shown to improve outcomes in scleroderma renal crisis.
*Labetalol*
* While labetalol can adequately control blood pressure, it is a **beta-blocker**, which is not the preferred first-line treatment for scleroderma renal crisis.
* Beta-blockers may also **worsen Raynaud's phenomenon**, which can be associated with scleroderma.
*Nifedipine*
* Nifedipine, a **calcium channel blocker**, can lower blood pressure but is not the first-line agent for scleroderma renal crisis.
* While effective for **Raynaud's phenomenon**, it does not provide the specific renal protection offered by ACE inhibitors in this context.
*Furosemide*
* Furosemide is a **loop diuretic** primarily used for fluid overload and is not indicated as a primary antihypertensive agent in this scenario, especially given the patient's **acute kidney injury**.
* Diuretics may exacerbate **hypovolemia**, which can worsen renal perfusion in patients with renal crisis.
*Hydrochlorothiazide*
* Hydrochlorothiazide is a **thiazide diuretic** primarily used for uncomplicated hypertension and fluid retention.
* It is **ineffective** in patients with a **creatinine clearance below 30 mL/min**, which this patient likely has given a creatinine of 3.1 mg/dL.
Question 144: A 71-year-old African American man diagnosed with high blood pressure presents to the outpatient clinic. In the clinic, his blood pressure is 161/88 mm Hg with a pulse of 88/min. He has had similar blood pressure measurements in the past, and you initiate captopril. He presents back shortly after initiation with extremely swollen lips, tongue, and face. After captopril is discontinued, what is the most appropriate step for the management of his high blood pressure?
A. Initiate a beta-blocker
B. Switch to ramipril
C. Initiate a thiazide diuretic (Correct Answer)
D. Reinitiate captopril
E. Initiate an ARB
Explanation: ***Initiate a thiazide diuretic***
- The patient experienced **angioedema** after taking **captopril**, which is an **ACE inhibitor**. This is a life-threatening adverse effect, and it indicates that all **ACE inhibitors** should be avoided in the future.
- Due to the risk of angioedema, a different class of antihypertensive should be used. Given his African American ethnicity, a **thiazide diuretic** or **calcium channel blocker** would be an appropriate initial choice for monotherapy if hypertension is stage 1, or combination therapy if stage 2 hypertension, otherwise, a second agent, such as a **calcium channel blocker**, can be added.
*Initiate a beta-blocker*
- While beta-blockers are a class of antihypertensive drugs, they are generally not preferred as **first-line monotherapy** for **hypertension**, especially in older African American patients, unless there are specific comorbidities like heart failure or coronary artery disease.
- The most appropriate first-line choice after **ACE inhibitor-induced angioedema** would be a thiazide diuretic or calcium channel blocker, as per ACC/AHA guidelines for primary hypertension.
*Switch to ramipril*
- **Ramipril** is also an **ACE inhibitor**, and the patient experienced **angioedema** with **captopril** (another ACE inhibitor).
- Cross-reactivity and recurrence of angioedema are high with other ACE inhibitors, making this choice extremely dangerous and contraindicated.
*Reinitiate captopril*
- The patient developed **angioedema**, a severe and potentially fatal hypersensitivity reaction, to **captopril**.
- Reinitiating the same drug could lead to recurrent, and potentially more severe, angioedema and is therefore absolutely contraindicated.
*Initiate an ARB*
- **Angiotensin receptor blockers (ARBs)**, while a different class from ACE inhibitors, act on the renin-angiotensin system and carry a **small but significant risk of cross-reactivity** leading to angioedema, especially in patients who have experienced it with an ACE inhibitor.
- Given the life-threatening nature of angioedema, it is generally recommended to avoid ARBs if a patient has a history of ACE inhibitor-induced angioedema.
Question 145: A 50-year-old woman presents with a severe headache and vomiting. She says that symptoms onset after attending a wine tasting at the local winery. She says that her headache is mostly at the back of her head and that she has been nauseous and vomited twice. Past medical history is significant for depression diagnosed 20 years ago but now well-controlled with medication. She also has significant vitamin D deficiency. Current medications are phenelzine and a vitamin D supplement. The patient denies any smoking history, alcohol or recreational drug use. On physical examination, the patient is diaphoretic. Her pupils are dilated. Which of the following is most likely to be elevated in this patient?
A. Blood pressure (Correct Answer)
B. Temperature
C. Creatine phosphokinase
D. Aspartate aminotransferase
E. Serum creatinine
Explanation: ***Blood pressure***
- The patient is taking **phenelzine**, a **monoamine oxidase inhibitor (MAOI)**. Consuming **tyramine-rich foods**, such as **wine** and fermented products, while on an MAOI can trigger a **hypertensive crisis**.
- Symptoms like severe headache (especially occipital), vomiting, diaphoresis, and dilated pupils are consistent with a **hypertensive crisis** induced by a **tyramine reaction**.
*Temperature*
- While fever can accompany a hypertensive crisis, it is not the most direct or consistently elevated vital sign in this specific scenario, which primarily describes symptoms related to **vasoconstriction** and **sympathetic overactivity**.
- Other conditions like **neuroleptic malignant syndrome** or **serotonin syndrome** are more typically associated with prominent hyperthermia, but the clinical picture here points more strongly to a tyramine reaction.
*Creatine phosphokinase*
- An elevated **creatine phosphokinase (CPK)** often indicates **muscle damage** or **rhabdomyolysis**. While severe hypertensive crises can sometimes lead to organ damage, CPK elevation is not a primary or immediate expected finding.
- This is more commonly elevated in conditions like **malignant hyperthermia**, **rhabdomyolysis**, or **myocardial infarction**, none of which are directly suggested by the initial presentation.
*Aspartate aminotransferase*
- **Aspartate aminotransferase (AST)** is an enzyme primarily associated with **liver damage**, although it can also be elevated in muscle or cardiac injury. There is no information in the vignette to suggest liver pathology.
- While severe organ damage can occur in prolonged or extreme hypertensive crises, **AST elevation** is not an immediate or characteristic feature of an acute **tyramine reaction**.
*Serum creatinine*
- **Serum creatinine** is a marker of **kidney function**. While kidney injury can occur in severe, prolonged hypertension, it is not an immediate finding expected during the acute onset of a **hypertensive crisis** from a tyramine reaction.
- There is no clinical information provided that would directly indicate immediate and significant renal impairment in this acute setting.
Question 146: A 52-year-old man comes to the physician for a routine health maintenance examination. He feels well. His blood pressure is 125/70 mm Hg. His glomerular filtration rate is calculated to be 105 mL/min/1.73 m2 and glucose clearance is calculated to be 103 mL/min. This patient is most likely being treated with which of the following agents?
A. Ifosfamide
B. Acarbose
C. Canagliflozin (Correct Answer)
D. Glipizide
E. Metformin
Explanation: ***Canagliflozin***
- The key finding is that **glucose clearance (103 mL/min) approximately equals GFR (105 mL/min)**, indicating nearly complete failure of glucose reabsorption.
- **Canagliflozin** is an **SGLT2 inhibitor** that blocks the sodium-glucose cotransporter 2 in the proximal tubule, preventing glucose reabsorption.
- This causes filtered glucose to be excreted in urine, resulting in **glucose clearance approaching GFR** - exactly what is seen in this patient.
- SGLT2 inhibitors are increasingly used as first-line agents in Type 2 Diabetes, especially with cardiovascular or renal benefits.
*Metformin*
- **Metformin** is a biguanide that decreases hepatic gluconeogenesis and increases peripheral insulin sensitivity.
- It does **NOT affect renal glucose handling** or glucose clearance, which would remain near zero in patients on metformin.
- The elevated glucose clearance in this patient rules out metformin monotherapy.
*Ifosfamide*
- **Ifosfamide** is an alkylating chemotherapy agent used for cancer treatment, not diabetes management.
- It can cause **Fanconi syndrome** (proximal tubule dysfunction) leading to glycosuria, but this would also cause decreased GFR, proteinuria, and electrolyte abnormalities.
- This patient's normal GFR and otherwise normal presentation makes ifosfamide-induced toxicity unlikely.
*Acarbose*
- **Acarbose** is an alpha-glucosidase inhibitor that slows carbohydrate absorption in the intestine.
- It works in the **GI tract**, not the kidneys, and does not affect glucose clearance.
- It would not explain the elevated renal glucose excretion seen here.
*Glipizide*
- **Glipizide** is a sulfonylurea that stimulates pancreatic insulin release.
- It does **NOT affect renal glucose handling** and would not cause elevated glucose clearance.
- The patient's glucose clearance pattern is inconsistent with sulfonylurea therapy.
Question 147: A 57-year-old man comes to the physician because of sudden-onset fever, malaise, and pain and swelling of his wrists and ankles that began a week ago. One month ago, he was started on hydralazine for adjunctive treatment of hypertension. His temperature is 37.8°C (100°F). Examination shows swelling, tenderness, warmth, and erythema of both wrists and ankles; range of motion is limited. Further evaluation is most likely to show an increased level of which of the following autoantibodies?
A. Anti-Jo-1
B. Anti-dsDNA
C. Anti-β2-glycoprotein
D. Anti-histone (Correct Answer)
E. Anti-Smith
Explanation: ***Anti-histone***
- The patient's presentation with **fever, malaise, polyarthritis**, and recent initiation of **hydralazine** strongly suggests **drug-induced lupus erythematosus (DILE)**.
- **Anti-histone antibodies** are the most common and characteristic autoantibody found in over 95% of cases of DILE.
*Anti-Jo-1*
- **Anti-Jo-1 antibodies** are positive in a subset of patients with **polymyositis** and **dermatomyositis**, often associated with interstitial lung disease and "mechanic's hands."
- These conditions typically involve **proximal muscle weakness** rather than predominantly joint pain and swelling as seen here.
*Anti-dsDNA*
- **Anti-dsDNA antibodies** are highly specific for **systemic lupus erythematosus (SLE)**, but are rarely positive in drug-induced lupus erythematosus (DILE).
- While DILE shares some features with SLE, the presence of these antibodies would favor a diagnosis of idiopathic SLE.
*Anti-β2-glycoprotein*
- **Anti-β2-glycoprotein antibodies** are associated with **antiphospholipid syndrome (APS)**, which presents with arterial or venous thrombosis and recurrent pregnancy loss.
- The patient's symptoms are primarily inflammatory arthritis, not thrombotic events.
*Anti-Smith*
- **Anti-Smith antibodies** are highly specific for **systemic lupus erythematosus (SLE)** and are rarely positive in drug-induced lupus erythematosus (DILE).
- Although highly specific for SLE, they are present in a minority of SLE patients (20-30%) and are not characteristic of DILE.
Question 148: A simple experiment is performed to measure the breakdown of sucrose into glucose and fructose by a gut enzyme that catalyzes this reaction. A glucose meter is used to follow the breakdown of sucrose into glucose. When no enzyme is added to the sucrose solution, the glucose meter will have a reading of 0 mg/dL; but when the enzyme is added, the glucose meter will start to show readings indicative of glucose being formed. Which of the following diabetic pharmacological agents, when added before the addition of the gut enzyme to the sucrose solution, will maintain a reading of 0 mg/dL?
A. Metformin
B. Acarbose (Correct Answer)
C. Exenatide
D. Glyburide
E. Insulin
Explanation: ***Acarbose***
- **Acarbose** is an **alpha-glucosidase inhibitor** that reduces the digestion and absorption of carbohydrates like sucrose in the small intestine.
- By inhibiting the enzyme that breaks down sucrose into glucose and fructose, it would prevent the formation of glucose, thus maintaining a reading of **0 mg/dL** in the experiment.
*Metformin*
- **Metformin** primarily acts by decreasing **hepatic glucose production** and increasing **insulin sensitivity** in peripheral tissues.
- It does not directly inhibit enzymes involved in the breakdown of dietary carbohydrates like sucrose in the gut.
*Exenatide*
- **Exenatide** is a **glucagon-like peptide-1 (GLP-1) receptor agonist** that enhances glucose-dependent insulin secretion, suppresses glucagon secretion, and slows gastric emptying.
- Its mechanism of action does not involve direct inhibition of carbohydrate-digesting enzymes in the gut.
*Glyburide*
- **Glyburide** is a **sulfonylurea** that stimulates **insulin release** from pancreatic beta cells by binding to and closing ATP-sensitive potassium channels.
- It does not interfere with the enzymatic breakdown of sucrose into glucose in the isolated gut enzyme system.
*Insulin*
- **Insulin** is a hormone that facilitates the uptake of glucose by cells and promotes its storage, thereby lowering blood glucose levels.
- It has no direct inhibitory effect on the enzyme that breaks down sucrose into glucose in the gut lumen.
Question 149: A patient presents with periods of severe headaches and flushing however every time they have come to the physician they have not experienced any symptoms. The only abnormal finding is a blood pressure of 175 mmHg/100 mmHg. It is determined that the optimal treatment for this patient is surgical. Prior to surgery which of the following noncompetitive inhibitors should be administered?
A. Phentolamine
B. Isoproterenol
C. Atropine
D. Propranolol
E. Phenoxybenzamine (Correct Answer)
Explanation: ***Phenoxybenzamine***
- This patient likely has a **pheochromocytoma**, which explains the episodic headaches, flushing, and hypertension. **Phenoxybenzamine** is a **non-competitive, irreversible alpha-adrenergic blocker** that is crucial for preoperative preparation to prevent a **hypertensive crisis** during surgery.
- Its **irreversible binding** provides sustained alpha blockade, essential to control blood pressure and avoid catecholamine-induced surges during tumor manipulation.
*Phentolamine*
- **Phentolamine** is a **competitive alpha-adrenergic blocker** used to manage acute hypertensive episodes, but it has a shorter duration of action.
- It is not preferred for sustained preoperative alpha blockade due to its **reversible nature** and potential for drug washout during surgery, which could lead to catecholamine surges.
*Isoproterenol*
- **Isoproterenol** is a **beta-adrenergic agonist** that increases heart rate and contractility, and causes bronchodilation.
- It would be contraindicated in a patient with pheochromocytoma as it could worsen hypertension and cardiac symptoms by stimulating beta receptors that are already overly sensitive to endogenous catecholamines.
*Atropine*
- **Atropine** is a **muscarinic acetylcholine receptor antagonist** that blocks parasympathetic effects, like bradycardia and salivation.
- It has no role in managing hypertension or the catecholamine excess seen in pheochromocytoma.
*Propranolol*
- **Propranolol** is a **non-selective beta-adrenergic blocker** that can be used to control tachycardia and arrhythmias in pheochromocytoma, but only *after* adequate alpha-blockade has been established.
- Using **propranolol alone** or before alpha-blockade can lead to **unopposed alpha-adrenergic stimulation**, resulting in a severe, life-threatening hypertensive crisis.
Question 150: A physician is choosing whether to prescribe losartan or lisinopril to treat hypertension in a 56-year-old male. Relative to losartan, one would expect treatment with lisinopril to produce which of the following changes in the circulating levels of these peptides?
A. Aldosterone increase; bradykinin decrease
B. Angiotensin II increase; bradykinin decrease
C. Renin decrease; angiotensin I increase
D. Bradykinin increase; angiotensin II decrease (Correct Answer)
E. Renin decrease; angiotensin II increase
Explanation: ***Bradykinin increase; angiotensin II decrease***
- **Lisinopril** is an **ACE inhibitor**, which directly blocks the conversion of **angiotensin I** to **angiotensin II**, leading to a decrease in circulating **angiotensin II** levels.
- ACE is also responsible for the breakdown of **bradykinin**, so inhibiting ACE with lisinopril will lead to an **increase in bradykinin** levels, contributing to vasodilation but also the characteristic cough.
*Aldosterone increase; bradykinin decrease*
- **Lisinopril** (an ACE inhibitor) decreases **angiotensin II**, which in turn leads to a **decrease in aldosterone** synthesis and release, not an increase.
- **Bradykinin** levels would increase due to ACE inhibition, as ACE is involved in its degradation.
*Angiotensin II increase; bradykinin decrease*
- **Lisinopril** directly inhibits the enzyme responsible for producing **angiotensin II**, thus leading to its **decrease**, not an increase.
- **Bradykinin** levels would increase because its degradation pathway (via ACE) is blocked, not decrease.
*Renin decrease; angiotensin I increase*
- **Lisinopril** reduces the negative feedback on **renin** release, leading to an **increase in renin** levels, not a decrease.
- While ACE is inhibited by lisinopril, this leads to an accumulation of its substrate, **angiotensin I**, resulting in an increase of angiotensin I.
*Renin decrease; angiotensin II increase*
- As an ACE inhibitor, lisinopril would lead to an **increase in renin** due to reduced negative feedback from angiotensin II, not a decrease.
- **Angiotensin II** levels would **decrease** because its production from angiotensin I is directly inhibited by lisinopril.
