A 74-year-old man presents to the clinic for a routine health checkup. He has been hypertensive for the past 20 years, and he has had congestive heart failure for the past 2 years. He is currently on captopril and claims to be compliant with his medication. His most recent echocardiogram report shows that his ejection fraction has been decreasing, so the physician decides to add spironolactone to his drug regimen. Which of the following complications should be most closely monitored for in this patient?
Q12
A 42-year-old African American woman presents to the physician’s office complaining of sudden onset chest pain. She describes the pain as sharp, non-radiating with improvement when she is sitting up and leaning forward. She denies fever, chills, or a cough, but she has had swollen hands and wrists for the past 3 weeks. Medical history is significant for chronic hypertension. She had an appendectomy at age 12. Medications include hydralazine and folic acid. Vital signs are normal except for a low-grade fever. On examination, the patient is in mild distress, especially in the supine position. The metacarpophalangeal and proximal interphalangeal joints are swollen and tender bilaterally. ECG shows diffuse ST elevations. Her antinuclear antibody is negative. Which of the following additional antibodies are expected to be found in this patient’s serum?
Q13
A 65-year-old man presents with hypercholesterolemia. Family history is significant for multiple cardiac deaths and other cardiovascular diseases. The patient reports a 40-pack-year smoking history. BMI is 28 kg/m2. Total cholesterol is 255 mg/dL and low-density lipoprotein (LDL) is more than 175 mg/dL. Lifestyle and dietary modifications are recommended, and the patient is prescribed a hypolipidemic drug. He returns for follow-up 4 weeks later complaining of muscle pains. Laboratory findings are significant for a significant increase in serum transaminases. Which of the following drugs is most likely responsible for this patient's symptoms on follow-up?
Q14
A 42-year-old man presents to the emergency room complaining of a painful, swollen tongue that is making it hard to talk and swallow. The patient denies trauma, trouble breathing, and skin rashes. The patient has no known allergies and a minimal past medical history, except for newly diagnosed hypertension for which he was just started on a new medication. The patient is afebrile, the blood pressure is 145/110 mm Hg, the heart rate is 88/min, and the O2 saturation is 97% on room air. What is the mechanism of this reaction?
Q15
A 44-year-old woman comes to the emergency department after waking up with facial swelling and with difficulties speaking and swallowing. She states that she does not have allergies or recently had insect bites. She has a 4-year history of hypertension and type 2 diabetes mellitus controlled with medication. Her pulse is 110/min, respirations are 20/min, and blood pressure is 140/90 mm Hg. Pulse oximetry on room air shows an oxygen saturation of 97%. On physical exam, she appears uncomfortable, with notable swelling of the lips and tongue. The remainder of the examination shows no abnormalities. Serum C4 levels are within normal limits. Which of the following is the most likely underlying mechanism of this patient's symptoms?
Q16
A 34-year-old gravida 2, para 1 woman at 37+6 weeks of gestation presents for elective cesarean delivery. She says she has been having increased fatigue over the past few weeks. Past medical history includes gestational hypertension for which she has been taking an antihypertensive drug twice daily since week 24. Her vital signs include: temperature 36.7°C (98.0°F), blood pressure 120/75 mm Hg, pulse 127/min. Physical examination reveals generalized pallor. Her laboratory results reveal normocytic anemia with anisocytosis, hemoglobin of 9 g/dL, a differential with 14% lymphocytes, an ESR of 22 mm/hr, and a reticulocyte production index of 3.1. A direct antiglobulin test is positive. LFTs, creatinine, ferritin level, vitamin B12 level, coagulation studies, and urinalysis are normal. Which of the following is the most likely diagnosis in this patient?
Q17
Four weeks after starting hydrochlorothiazide, a 49-year-old man with hypertension comes to the physician because of muscle cramps and weakness. His home medications also include amlodipine. His blood pressure today is 176/87 mm Hg. Physical examination shows no abnormalities. The precordial leads of a 12-lead ECG are shown. The addition of which of the following is most likely to have prevented this patient's condition?
Q18
A 55-year-old man with hypertension, hyperlipidemia, type 2 diabetes mellitus, and asthma comes to the physician because of a 2-month history of intermittent dry, hacking cough. He does not have fever, chest pain, or shortness of breath. He does not smoke cigarettes. Current medications include simvastatin, metformin, albuterol, and ramipril. His temperature is 37°C (98.6°F), pulse is 87/min, and blood pressure is 142/88 mm Hg. Cardiopulmonary examination shows no abnormalities. Which of the following is the most appropriate next step in management?
Q19
A 60-year-old African-American male with no active medical problems presents to his primary care physician for a general checkup. His blood pressure on the previous visit was 145/90, and his blood pressure at this visit is found to be 150/95. He is prescribed hydrochlorothiazide, a thiazide diuretic, to treat his hypertension. The serum level of which of the following is likely to decrease in response to his treatment?
Q20
A 52-year-old man presents to his primary care physician for an annual check-up. He says that he has no significant developments over the last year and that he has been feeling well in general. On presentation, his temperature is 98.6°F (37°C), blood pressure is 140/95 mmHg, pulse is 85/min, and respirations are 12/min. This is the third time that he has had elevated blood pressure so his physician suggests that he start taking a medication for hypertension. The patient is a biologist so he researches this medication after returning home. He finds that the medication can either decrease or increase the level of cyclic adenosine monophosphate depending on whether there is endogenous substrate around. Which of the following medications is most likely being described here?
Antihypertensives US Medical PG Practice Questions and MCQs
Question 11: A 74-year-old man presents to the clinic for a routine health checkup. He has been hypertensive for the past 20 years, and he has had congestive heart failure for the past 2 years. He is currently on captopril and claims to be compliant with his medication. His most recent echocardiogram report shows that his ejection fraction has been decreasing, so the physician decides to add spironolactone to his drug regimen. Which of the following complications should be most closely monitored for in this patient?
A. Hypernatremia
B. Hyperkalemia (Correct Answer)
C. Azotemia
D. Alkalosis
E. Gynecomastia
Explanation: **Hyperkalemia (Correct)**
- **Spironolactone** is a **potassium-sparing diuretic** and aldosterone antagonist, which can lead to increased serum potassium levels
- The patient is also on **captopril**, an ACE inhibitor, which also decreases aldosterone and can contribute to hyperkalemia
- **This combination significantly increases the risk of hyperkalemia**, making it the most critical complication to monitor closely
- Hyperkalemia can lead to life-threatening cardiac arrhythmias, requiring immediate attention
*Hypernatremia (Incorrect)*
- Spironolactone, by blocking aldosterone, mildly promotes **sodium excretion**, making hypernatremia (high sodium) less likely
- While other diuretics can cause hyponatremia due to volume depletion, spironolactone's primary risk isn't dysregulation of sodium leading to hypernatremia
*Azotemia (Incorrect)*
- Azotemia refers to an increase in **urea and creatinine** in the blood, often indicating kidney dysfunction
- While spironolactone can sometimes worsen renal function, it's not the most direct or immediate concern for monitoring compared to potassium levels, especially in a stable patient without acute kidney injury
- **ACE inhibitors** like captopril can sometimes induce mild azotemia, but monitoring for hyperkalemia is a more direct and significant concern with the addition of spironolactone
*Alkalosis (Incorrect)*
- **Spironolactone** can cause **metabolic acidosis** (not alkalosis) due to its effect on potassium and hydrogen excretion, making alkalosis an unlikely complication
- Most other diuretics, like loop or thiazide diuretics, are more commonly associated with metabolic alkalosis
*Gynecomastia (Incorrect)*
- While **gynecomastia** is a known side effect of spironolactone due to its **antiandrogenic effects**, it is a chronic side effect that develops over time
- This is not an acute or immediately life-threatening complication requiring close monitoring in the same way hyperkalemia does
- The immediate focus of monitoring after starting spironolactone is on electrolyte imbalances, particularly potassium levels
Question 12: A 42-year-old African American woman presents to the physician’s office complaining of sudden onset chest pain. She describes the pain as sharp, non-radiating with improvement when she is sitting up and leaning forward. She denies fever, chills, or a cough, but she has had swollen hands and wrists for the past 3 weeks. Medical history is significant for chronic hypertension. She had an appendectomy at age 12. Medications include hydralazine and folic acid. Vital signs are normal except for a low-grade fever. On examination, the patient is in mild distress, especially in the supine position. The metacarpophalangeal and proximal interphalangeal joints are swollen and tender bilaterally. ECG shows diffuse ST elevations. Her antinuclear antibody is negative. Which of the following additional antibodies are expected to be found in this patient’s serum?
A. Anti-cyclic citrullinated antibodies
B. Anti-histone antibodies (Correct Answer)
C. Anti-topoisomerase I antibodies
D. Anti-mitochondrial antibodies
E. Anti-cardiolipin antibodies
Explanation: ***Anti-histone antibodies***
- The patient's symptoms, including **diffuse ST elevations** (suggesting pericarditis) and joint pain, combined with a history of **hydralazine** use, are highly indicative of **drug-induced lupus**.
- **Anti-histone antibodies** are positive in over 95% of cases of drug-induced lupus.
*Anti-cyclic citrullinated antibodies*
- These antibodies are highly specific for **rheumatoid arthritis**, a condition not supported by the clinical picture (e.g., pericarditis, diffuse ST elevation, specific medication history).
- While the patient has arthritis, the **acute pericarditis** and **hydralazine use** point away from rheumatoid arthritis.
*Anti-topoisomerase I antibodies*
- These antibodies are characteristic of **systemic sclerosis (scleroderma)**, particularly the diffuse cutaneous form.
- The patient's presentation with acute pericarditis and reversible joint swelling is not typical for **scleroderma**.
*Anti-mitochondrial antibodies*
- These antibodies are the serological hallmark of **primary biliary cholangitis**, a chronic autoimmune liver disease.
- The patient's symptoms are unrelated to liver disease.
*Anti-cardiolipin antibodies*
- These antibodies are associated with **antiphospholipid syndrome**, which can cause **thrombosis** and recurrent pregnancy loss but does not typically present with the acute pericarditis and joint pain described in this case, nor is it linked specifically to hydralazine.
- While lupus can be associated with antiphospholipid syndrome, the most direct antibody for **drug-induced lupus** is anti-histone.
Question 13: A 65-year-old man presents with hypercholesterolemia. Family history is significant for multiple cardiac deaths and other cardiovascular diseases. The patient reports a 40-pack-year smoking history. BMI is 28 kg/m2. Total cholesterol is 255 mg/dL and low-density lipoprotein (LDL) is more than 175 mg/dL. Lifestyle and dietary modifications are recommended, and the patient is prescribed a hypolipidemic drug. He returns for follow-up 4 weeks later complaining of muscle pains. Laboratory findings are significant for a significant increase in serum transaminases. Which of the following drugs is most likely responsible for this patient's symptoms on follow-up?
A. Atorvastatin (Correct Answer)
B. Glyceryl trinitrate
C. Colestipol
D. Gemfibrozil
E. Nifedipine
Explanation: ***Atorvastatin***
- **Statins** (e.g., atorvastatin) are the **first-line treatment for elevated LDL cholesterol** and commonly cause **myopathy** (muscle pain) and **hepatotoxicity** (elevated transaminases).
- The combination of **muscle pains** and significantly increased **serum transaminases** is a classic presentation of statin-induced adverse effects.
- Given the patient's LDL >175 mg/dL, a statin would be the most appropriate initial hypolipidemic therapy, making this the most likely culprit.
*Glyceryl trinitrate*
- This is a **nitrate** used for angina, primarily causing **vasodilation**.
- **Not a hypolipidemic agent** and would not be prescribed for hypercholesterolemia.
- Common side effects include headache, flushing, and hypotension, but not muscle pain or elevated transaminases.
*Colestipol*
- **Colestipol** is a **bile acid sequestrant** used as a hypolipidemic agent.
- Common side effects are gastrointestinal: **constipation**, bloating, and nausea.
- Does **not** typically cause muscle pain or elevated liver enzymes.
*Gemfibrozil*
- **Gemfibrozil** is a **fibrate** primarily used to lower triglycerides and increase HDL, rather than LDL.
- While fibrates can rarely cause myopathy and elevated transaminases (especially when combined with statins), they are **not first-line for isolated LDL elevation**.
- Given this patient's primary problem is elevated LDL (>175 mg/dL) with normal triglycerides implied, a statin would be prescribed, not a fibrate.
*Nifedipine*
- **Nifedipine** is a **calcium channel blocker** used for hypertension and angina.
- **Not a hypolipidemic agent** and would not be prescribed for hypercholesterolemia.
- Common side effects include peripheral edema, headache, flushing, and dizziness, but not muscle pain or elevated transaminases.
Question 14: A 42-year-old man presents to the emergency room complaining of a painful, swollen tongue that is making it hard to talk and swallow. The patient denies trauma, trouble breathing, and skin rashes. The patient has no known allergies and a minimal past medical history, except for newly diagnosed hypertension for which he was just started on a new medication. The patient is afebrile, the blood pressure is 145/110 mm Hg, the heart rate is 88/min, and the O2 saturation is 97% on room air. What is the mechanism of this reaction?
A. Inhibition of 17-alpha-hydroxylase
B. Histamine release
C. Increased angiotensin II due to decreased receptor response
D. Decreased bradykinin degradation (Correct Answer)
E. Decreased levels of C1 inhibitor protein
Explanation: ***Decreased bradykinin degradation***
- The patient's symptoms of **angioedema** (painful, swollen tongue, difficulty talking and swallowing) rapidly developing after starting a new medication for hypertension strongly suggest an **ACE inhibitor-induced** reaction.
- ACE inhibitors block the enzyme that normally degrades **bradykinin**, leading to an accumulation of bradykinin, which causes **vasodilation** and increased vascular permeability, manifesting as angioedema.
*Inhibition of 17-alpha-hydroxylase*
- This mechanism is associated with drugs like **abiraterone**, used in prostate cancer, affecting **steroid hormone synthesis**.
- It would lead to changes in sex hormones and mineralocorticoids, not acute angioedema.
*Histamine release*
- **Histamine release** is characteristic of type I hypersensitivity reactions (allergies) and typically presents with urticaria, pruritus, and bronchospasm, which are absent here.
- Angioedema from histamine release is usually accompanied by other **allergic symptoms**, and the patient denies allergies.
*Increased angiotensin II due to decreased receptor response*
- This describes the mechanism of **angiotensin receptor blockers (ARBs)**, where the body compensates for receptor blockade by increasing angiotensin II levels.
- While ARBs can also cause angioedema, the underlying mechanism for the angioedema is often still related to bradykinin accumulation (though less common than with ACE inhibitors), not increased angiotensin II itself causing the swelling.
*Decreased levels of C1 inhibitor protein*
- This is the mechanism for **hereditary or acquired angioedema** (HAE/AAE), characterized by recurrent episodes of swelling without urticaria, often triggered by stress or trauma.
- While it causes similar symptoms, it is not drug-induced in the typical acute presentation following a new medication, and the patient has no history suggesting a chronic condition.
Question 15: A 44-year-old woman comes to the emergency department after waking up with facial swelling and with difficulties speaking and swallowing. She states that she does not have allergies or recently had insect bites. She has a 4-year history of hypertension and type 2 diabetes mellitus controlled with medication. Her pulse is 110/min, respirations are 20/min, and blood pressure is 140/90 mm Hg. Pulse oximetry on room air shows an oxygen saturation of 97%. On physical exam, she appears uncomfortable, with notable swelling of the lips and tongue. The remainder of the examination shows no abnormalities. Serum C4 levels are within normal limits. Which of the following is the most likely underlying mechanism of this patient's symptoms?
A. Impaired bradykinin metabolism (Correct Answer)
B. IgE-mediated histamine release
C. Anaphylactoid reaction
D. Type 2 hypersensitivity reaction
E. Immune-complex deposition
Explanation: ***Impaired bradykinin metabolism***
- The patient's presentation with **angioedema** (facial swelling, difficulty speaking/swallowing due to lip and tongue swelling) without urticaria or pruritus, and **normal C4 levels**, is consistent with **ACE inhibitor-induced angioedema**.
- ACE inhibitors (commonly used for hypertension) block angiotensin-converting enzyme, which normally degrades bradykinin. **Impaired bradykinin breakdown** leads to accumulation, causing increased vascular permeability and angioedema.
- Normal C4 levels rule out C1 esterase inhibitor deficiency (hereditary angioedema), making drug-induced angioedema the most likely diagnosis in this patient on antihypertensive therapy.
*IgE-mediated histamine release*
- This mechanism typically causes **urticaria** (hives), pruritus, and often bronchospasm or hypotension, which are not described in this patient.
- **Allergic reactions** involving IgE usually involve a clear allergen exposure, which is absent here ("no allergies or recent insect bites").
*Anaphylactoid reaction*
- Anaphylactoid reactions involve mast cell and basophil degranulation, releasing histamine and other mediators **without IgE involvement**.
- While it can cause angioedema, it often presents with other systemic symptoms like flushing, itching, and respiratory distress. The absence of a clear trigger and presence of isolated angioedema makes bradykinin-mediated angioedema more likely.
*Type 2 hypersensitivity reaction*
- Type 2 hypersensitivity involves **antibody-mediated cytotoxicity** and cell lysis, seen in conditions like autoimmune hemolytic anemia or Goodpasture syndrome.
- This mechanism does not typically manifest as isolated angioedema with facial and airway swelling.
*Immune-complex deposition*
- This refers to a **Type 3 hypersensitivity reaction**, where antigen-antibody complexes deposit in tissues, leading to inflammation (e.g., serum sickness, lupus nephritis).
- This mechanism does not explain the acute, localized angioedema observed in this patient.
Question 16: A 34-year-old gravida 2, para 1 woman at 37+6 weeks of gestation presents for elective cesarean delivery. She says she has been having increased fatigue over the past few weeks. Past medical history includes gestational hypertension for which she has been taking an antihypertensive drug twice daily since week 24. Her vital signs include: temperature 36.7°C (98.0°F), blood pressure 120/75 mm Hg, pulse 127/min. Physical examination reveals generalized pallor. Her laboratory results reveal normocytic anemia with anisocytosis, hemoglobin of 9 g/dL, a differential with 14% lymphocytes, an ESR of 22 mm/hr, and a reticulocyte production index of 3.1. A direct antiglobulin test is positive. LFTs, creatinine, ferritin level, vitamin B12 level, coagulation studies, and urinalysis are normal. Which of the following is the most likely diagnosis in this patient?
A. Drug-induced immune hemolytic reaction (Correct Answer)
B. Hereditary spherocytosis
C. Preeclampsia
D. Normal pregnancy
E. HELLP syndrome
Explanation: ***Drug-induced immune hemolytic reaction***
- The positive **direct antiglobulin test (DAT)** combined with a history of **antihypertensive drug use** in a pregnant patient with **normocytic anemia** and an **elevated reticulocyte production index** strongly suggests a drug-induced immune hemolytic reaction.
- Certain antihypertensive medications, such as **alpha-methyldopa**, are known to cause a positive DAT and hemolytic anemia through drug-induced antibody formation.
*Hereditary spherocytosis*
- Hereditary spherocytosis causes **hemolytic anemia** but typically presents with a **negative DAT** because it is a membrane defect, not an immune-mediated process.
- This is usually a lifelong condition that would likely have been diagnosed earlier, not presenting acutely in late pregnancy.
- The positive DAT in this case effectively rules out uncomplicated hereditary spherocytosis.
*Preeclampsia*
- Preeclampsia involves **hypertension** and **proteinuria**, but **autoimmune hemolytic anemia** with a positive DAT is not a typical feature.
- The patient's blood pressure is well-controlled at 120/75 mmHg, and both creatinine and urinalysis are normal, ruling out preeclampsia.
*Normal pregnancy*
- **Physiological anemia of pregnancy** is typically dilutional and mild, and does not present with a **positive DAT** or a significantly elevated **reticulocyte production index** as seen in this case.
- The degree of pallor, tachycardia, and the laboratory findings, particularly the positive DAT, indicate a pathological hemolytic process.
*HELLP syndrome*
- **HELLP syndrome** (Hemolysis, Elevated Liver enzymes, Low Platelets) is characterized by **thrombocytopenia** and **elevated liver enzymes**, neither of which are present in this patient.
- While it involves hemolysis, the normal LFTs and absence of thrombocytopenia rule out HELLP syndrome.
Question 17: Four weeks after starting hydrochlorothiazide, a 49-year-old man with hypertension comes to the physician because of muscle cramps and weakness. His home medications also include amlodipine. His blood pressure today is 176/87 mm Hg. Physical examination shows no abnormalities. The precordial leads of a 12-lead ECG are shown. The addition of which of the following is most likely to have prevented this patient's condition?
A. Hydralazine
B. Clonidine
C. Eplerenone (Correct Answer)
D. Torsemide
E. Nifedipine
Explanation: ***Eplerenone***
- The patient's symptoms of **muscle cramps and weakness** after starting hydrochlorothiazide strongly suggest **hypokalemia**, a common adverse effect of thiazide diuretics. The ECG showing **QT prolongation with prominent U waves** further supports hypokalemia.
- **Eplerenone** is a potassium-sparing diuretic and aldosterone antagonist that would counteract the potassium loss caused by hydrochlorothiazide, thus preventing hypokalemia.
*Hydralazine*
- **Hydralazine** is a direct vasodilator primarily used for hypertension that causes **reflex tachycardia and fluid retention**.
- It does not influence potassium levels and would not prevent hypokalemia.
*Clonidine*
- **Clonidine** is a centrally acting alpha-2 agonist that reduces sympathetic outflow, causing **vasodilation and reduced heart rate**.
- It has no known effect on potassium balance and would not prevent diuretic-induced hypokalemia.
*Torsemide*
- **Torsemide** is a loop diuretic, which is also associated with **potassium wasting**, similar to or even more pronounced than thiazide diuretics.
- Adding torsemide would worsen, not prevent, the patient's hypokalemia.
*Nifedipine*
- **Nifedipine** is a dihydropyridine calcium channel blocker that causes **peripheral vasodilation** and does not impact potassium levels.
- It would not prevent hydrochlorothiazide-induced hypokalemia.
Question 18: A 55-year-old man with hypertension, hyperlipidemia, type 2 diabetes mellitus, and asthma comes to the physician because of a 2-month history of intermittent dry, hacking cough. He does not have fever, chest pain, or shortness of breath. He does not smoke cigarettes. Current medications include simvastatin, metformin, albuterol, and ramipril. His temperature is 37°C (98.6°F), pulse is 87/min, and blood pressure is 142/88 mm Hg. Cardiopulmonary examination shows no abnormalities. Which of the following is the most appropriate next step in management?
A. Start dextromethorphan and increase frequency of albuterol
B. Stop ramipril and start candesartan (Correct Answer)
C. Stop simvastatin and start atorvastatin
D. Stop ramipril and start lisinopril
E. Stop albuterol and start salmeterol
Explanation: ***Stop ramipril and start candesartan***
- The patient's **dry, hacking cough** is a common side effect of **ACE inhibitors** like ramipril, occurring in up to 20% of patients [1], [4]. Switching to an **angiotensin receptor blocker (ARB)** like candesartan avoids this side effect as ARBs do not inhibit bradykinin breakdown [1], [4].
- Given the patient's other well-controlled chronic conditions and the absence of other respiratory symptoms (fever, chest pain, shortness of breath), an **ACE inhibitor-induced cough** is the most likely diagnosis [2].
*Start dextromethorphan and increase frequency of albuterol*
- **Dextromethorphan** is a cough suppressant, but it does not address the underlying cause of the cough if it is medication-induced, and the cough is likely due to the ramipril.
- Increasing the frequency of **albuterol** (a short-acting beta-agonist) is inappropriate as the patient does not have symptoms of asthma exacerbation (e.g., shortness of breath, wheezing), and the cough is dry and persistent, not typical of asthmatic bronchoconstriction [3].
*Stop simvastatin and start atorvastatin*
- There is no indication to change the **statin** medication. **Simvastatin** is an effective HMG-CoA reductase inhibitor, and it is not associated with cough.
- This change would not address the patient's presenting symptom of a dry, hacking cough.
*Stop ramipril and start lisinopril*
- Both **ramipril** and **lisinopril** are **ACE inhibitors** and share the same mechanism of action [1].
- Switching from one ACE inhibitor to another would likely result in the continuation of the **cough** side effect, as it is a class effect [4].
*Stop albuterol and start salmeterol*
- This patient's dry cough is unlikely to be an asthma symptom given the chronic nature and lack of other respiratory symptoms, suggesting the albuterol is not the issue.
- **Salmeterol** is a long-acting beta-agonist (LABA) used for maintenance therapy in asthma; switching to it from albuterol would not address a medication-induced cough and could be inappropriate without further asthma assessment [3].
Question 19: A 60-year-old African-American male with no active medical problems presents to his primary care physician for a general checkup. His blood pressure on the previous visit was 145/90, and his blood pressure at this visit is found to be 150/95. He is prescribed hydrochlorothiazide, a thiazide diuretic, to treat his hypertension. The serum level of which of the following is likely to decrease in response to his treatment?
A. Uric acid
B. Cholesterol
C. Glucose
D. Potassium (Correct Answer)
E. Calcium
Explanation: ***Potassium (Correct Answer)***
- **Thiazide diuretics** inhibit the Na-Cl cotransporter in the **distal convoluted tubule**, leading to increased delivery of sodium to the collecting duct
- This increased sodium delivery promotes the **exchange of sodium for potassium** and hydrogen ions, resulting in increased potassium excretion
- The result is **hypokalemia** (decreased serum potassium), which is a classic adverse effect requiring monitoring
- Potassium supplementation or potassium-sparing diuretics may be needed in some patients
*Uric acid (Incorrect)*
- Thiazide diuretics **decrease the renal excretion of uric acid** by competing for secretion in the proximal tubule
- This leads to **hyperuricemia** (increased serum uric acid), not decreased levels
- Can potentially precipitate **gout attacks** in susceptible individuals
*Cholesterol (Incorrect)*
- Thiazide diuretics cause a **slight increase in total cholesterol** and LDL cholesterol, particularly at higher doses
- This effect is generally mild and non-progressive with long-term use
- Serum cholesterol increases, not decreases
*Glucose (Incorrect)*
- Thiazide diuretics can **impair glucose tolerance** and raise blood glucose levels
- This effect is particularly notable in patients with pre-existing diabetes or metabolic syndrome
- Mechanism involves decreased insulin secretion and increased insulin resistance
- Results in **hyperglycemia** (increased serum glucose), not decreased levels
*Calcium (Incorrect)*
- Thiazide diuretics **decrease calcium excretion** by promoting reabsorption in the distal convoluted tubule
- This leads to **increased serum calcium** (hypercalcemia), not decreased levels
- This effect can be therapeutically useful in patients with hypercalciuria or kidney stones
- Can unmask or worsen hypercalcemia in patients with hyperparathyroidism
Question 20: A 52-year-old man presents to his primary care physician for an annual check-up. He says that he has no significant developments over the last year and that he has been feeling well in general. On presentation, his temperature is 98.6°F (37°C), blood pressure is 140/95 mmHg, pulse is 85/min, and respirations are 12/min. This is the third time that he has had elevated blood pressure so his physician suggests that he start taking a medication for hypertension. The patient is a biologist so he researches this medication after returning home. He finds that the medication can either decrease or increase the level of cyclic adenosine monophosphate depending on whether there is endogenous substrate around. Which of the following medications is most likely being described here?
A. Carvedilol
B. Atenolol
C. Propranolol
D. Esmolol
E. Pindolol (Correct Answer)
Explanation: ***Pindolol***
- **Pindolol** is a **beta-blocker** with **intrinsic sympathomimetic activity (ISA)**, meaning it can act as a partial agonist at beta-adrenergic receptors.
- In the absence of endogenous sympathetic stimulation, pindolol can **mildly stimulate** the receptor, increasing cAMP; however, in the presence of high sympathetic tone (endogenous substrate), it acts as an antagonist, **blocking** the effect of norepinephrine and decreasing cAMP.
*Carvedilol*
- **Carvedilol** is a **non-selective beta-blocker** and an **alpha-1 blocker** used in hypertension and heart failure, but it **lacks intrinsic sympathomimetic activity (ISA)**.
- Its effects on cAMP are solely antagonistic, blocking the increase caused by endogenous catecholamines.
*Atenolol*
- **Atenolol** is a **selective beta-1 blocker** (cardioselective) that **lacks intrinsic sympathomimetic activity (ISA)**.
- It works by blocking beta-1 receptors in the heart, leading to decreased heart rate and contractility, thereby reducing blood pressure, and consistently reduces cAMP levels.
*Propranolol*
- **Propranolol** is a **non-selective beta-blocker** that **lacks intrinsic sympathomimetic activity (ISA)**.
- It blocks both beta-1 and beta-2 adrenergic receptors, leading to a decrease in heart rate, contractility, and renin release, consistently leading to a reduction in cAMP.
*Esmolol*
- **Esmolol** is an **ultrashort-acting, selective beta-1 blocker** that **lacks intrinsic sympathomimetic activity (ISA)**.
- Due to its rapid onset and short duration of action, it is primarily used intravenously in acute settings for rate control in arrhythmias or hypertension, consistently reducing cAMP.