Long-term acetazolamide commonly causes which acid-base change?

Hyperchloraemic metabolic acidosis

Palpitations after the first dose of immediate-release nifedipine are best explained by:

Reflex sympathetic activation after vasodilatation

Increased cardiac preload from fluid retention

Blockade of vagal tone by the drug

Direct beta-1 receptor stimulation by nifedipine itself

A patient with chronic kidney disease takes ramipril and spironolactone, and the potassium is 6.1 mmol/L. Which mechanism of spironolactone contributes most?

Blocking aldosterone receptors, which reduces potassium secretion

Blocking Na-K-2Cl in the thick ascending limb of the loop of Henle

Increasing potassium uptake into the muscle cells

Increasing renin release from the juxtaglomerular cells

A patient with COPD has pH 7.34, PaCO2 70 mmHg and HCO3 36 mmol/L. For every 10 mmHg rise in PaCO2, the chronic compensation is a rise in HCO3 of about 3.5 mmol/L. The best interpretation is:

Chronic respiratory acidosis with renal compensation

Acute respiratory acidosis with minimal compensation

Pure metabolic acidosis with respiratory compensation

Metabolic alkalosis with respiratory compensation

Physiology and pathophysiology

50 Gulf Prometric Pharmacist (DHA, DOH, MOH, SCFHS, QCHP) practice questions on Physiology and pathophysiology, part of Basic Biomedical Sciences. The first 25 are below; the first 5 with answers and explanations (tap Show answer after you have chosen), the rest in Learn with a free account.

Question 1 · Medium
Long-term acetazolamide commonly causes which acid-base change?
1. AHyperchloraemic metabolic acidosis
2. BMetabolic alkalosis
3. CRespiratory alkalosis
4. DRespiratory acidosis
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Answer: A · Hyperchloraemic metabolic acidosis
Acetazolamide inhibits carbonic anhydrase in the proximal tubule, so bicarbonate reabsorption falls and bicarbonate is lost in the urine. Chloride rises to replace it, giving a normal-anion-gap acidosis. Loop and thiazide diuretics tend to cause alkalosis.
- B: Alkalosis is produced by loop and thiazide diuretics.
- C: Alkalosis would require bicarbonate retention.
- D: It reduces bicarbonate rather than affecting ventilation as the primary change.
Remember this
Acetazolamide causes bicarbonate loss and hyperchloraemic (normal anion gap) metabolic acidosis.
Question 2 · Medium
Palpitations after the first dose of immediate-release nifedipine are best explained by:
1. AIncreased cardiac preload from fluid retention
2. BReflex sympathetic activation after vasodilatation
3. CBlockade of vagal tone by the drug
4. DDirect beta-1 receptor stimulation by nifedipine itself
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Answer: B · Reflex sympathetic activation after vasodilatation
Rapid arterial vasodilatation lowers blood pressure, and the baroreceptor reflex responds with sympathetic activation and tachycardia. Slow-release products and combination with a beta-blocker reduce this. Nifedipine has no direct effect on beta receptors.
- A: Vasodilatation reduces rather than increases preload.
- C: It does not block the vagus.
- D: Nifedipine is a calcium channel blocker and has no beta-agonist action.
Remember this
Vasodilator reflex tachycardia comes from baroreceptor-driven sympathetic activation; slow-release forms or beta-blockers reduce it.
Question 3 · Medium
A patient with chronic kidney disease takes ramipril and spironolactone, and the potassium is 6.1 mmol/L. Which mechanism of spironolactone contributes most?
1. ABlocking aldosterone receptors, which reduces potassium secretion
2. BBlocking Na-K-2Cl in the thick ascending limb of the loop of Henle
3. CIncreasing potassium uptake into the muscle cells
4. DIncreasing renin release from the juxtaglomerular cells
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Answer: A · Blocking aldosterone receptors, which reduces potassium secretion
Aldosterone normally drives potassium secretion in the principal cells, and spironolactone blocks its receptor so potassium is retained. Together with an ACE inhibitor, which lowers aldosterone, and reduced GFR, hyperkalaemia is likely. Potassium and creatinine should be monitored.
- B: Blocking NKCC2 is the loop diuretic action and causes potassium loss.
- C: Potassium uptake into cells is the insulin effect and lowers serum potassium.
- D: Renin release does not cause potassium retention directly.
Remember this
Spironolactone plus an ACE inhibitor in CKD carries a high hyperkalaemia risk; monitor potassium and creatinine.
Question 4 · Easy
Omeprazole acts by inhibiting the H+/K+ ATPase pump in which cells?
1. AGastric G cells
2. BGastric parietal cells
3. CMucous neck cells
4. DGastric chief cells
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Answer: B · Gastric parietal cells
The proton pump in the canalicular membrane of parietal cells is the final step of acid secretion, and PPIs inhibit it irreversibly. Chief cells secrete pepsinogen, G cells secrete gastrin and mucous neck cells secrete mucus. Blocking the final common step reduces acid output more than blocking one stimulus.
- A: G cells secrete gastrin.
- C: Mucous neck cells secrete protective mucus.
- D: Chief cells secrete pepsinogen.
Remember this
PPIs irreversibly block the H+/K+ ATPase proton pump of the parietal cell.
Question 5 · Hard
A patient with COPD has pH 7.34, PaCO2 70 mmHg and HCO3 36 mmol/L. For every 10 mmHg rise in PaCO2, the chronic compensation is a rise in HCO3 of about 3.5 mmol/L. The best interpretation is:
1. AAcute respiratory acidosis with minimal compensation
2. BPure metabolic acidosis with respiratory compensation
3. CChronic respiratory acidosis with renal compensation
4. DMetabolic alkalosis with respiratory compensation
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Answer: C · Chronic respiratory acidosis with renal compensation
A PaCO2 rise of 30 above 40 should raise bicarbonate by about 10 in chronic compensation, so the expected HCO3 is about 34, close to the measured 36. The near-normal pH shows that the kidneys have retained bicarbonate over days. In acute respiratory acidosis the bicarbonate would be about 27 and the pH much lower.
- A: Acute acidosis would show a lower pH and HCO3 near 27.
- B: A raised PaCO2 and bicarbonate do not fit metabolic acidosis.
- D: Metabolic alkalosis would show a high pH.
Remember this
In chronic respiratory acidosis, HCO3 rises about 3.5 mmol/L per 10 mmHg rise in PaCO2.
Question 6 · Medium
Colestyramine reduces plasma LDL cholesterol mainly through:
1. AIncreasing the breakdown of LDL receptors on liver cells
2. BBlocking cholesterol absorption at the small intestinal brush border membrane
3. CInhibiting HMG-CoA reductase in the liver to cut cholesterol synthesis
4. DBinding bile acids in the gut, so the liver uses cholesterol to make more
Answer and explanation in LearnFree account
Question 7 · Medium
Stimulation of cardiac beta-1 receptors increases heart rate and contractility through which signalling pathway?
1. AGq protein activation, raising IP3
2. BGi protein activation, lowering cAMP
3. CGs protein activation, raising cAMP
4. DDirect opening of potassium channels
Answer and explanation in LearnFree account
Question 8 · Hard
A man has a glomerular filtration rate of 90 mL/min and a renal plasma flow of 450 mL/min. His filtration fraction is:
1. A5%
2. B80%
3. C40%
4. D20%
Answer and explanation in LearnFree account
Question 9 · Hard
A patient has an end-diastolic volume of 140 mL, an end-systolic volume of 90 mL and a heart rate of 90 beats/min. What is the cardiac output?
1. A12.6 L/min
2. B3.6 L/min
3. C4.5 L/min
4. D8.1 L/min
Answer and explanation in LearnFree account
Question 10 · Medium
Class I antiarrhythmic drugs such as flecainide slow conduction in the ventricle mainly by blocking which phase of the action potential?
1. APhase 2, the plateau
2. BPhase 0, the fast sodium influx
3. CPhase 4, resting potential
4. DPhase 3, repolarisation
Answer and explanation in LearnFree account
Question 11 · Easy
Which part of the nephron reabsorbs the largest share (about two thirds) of filtered sodium and water?
1. ACollecting duct
2. BDistal convoluted tubule
3. CThick ascending limb of the loop of Henle
4. DProximal convoluted tubule
Answer and explanation in LearnFree account
Question 12 · Medium
Propranolol reduces the frequency of exertional angina mainly by lowering:
1. ACoronary artery vasospasm
2. BPreload through venodilatation
3. CHeart rate and contractility
4. DAfterload through arteriolar dilatation
Answer and explanation in LearnFree account
Question 13 · Medium
Constipation continues in a patient on long-term morphine because tolerance to this effect does not develop. The effect arises from:
1. ARaised colonic water absorption as the main effect of the drug
2. BMu-receptor activation in the myenteric plexus, reducing propulsive motility
3. CExcess bile acid reaching the colon, which draws water into the lumen and speeds transit
4. DBlockade of cholinergic receptors in the gut wall, with slowed secretion
Answer and explanation in LearnFree account
Question 14 · Medium
A dehydrated patient on a loop diuretic takes ibuprofen and develops acute kidney injury. The main reason for this is that the NSAID:
1. ADilates the efferent arteriole and so lowers filtration pressure
2. BIncreases renin secretion and so raises renal angiotensin II levels
3. CBlocks prostaglandin-mediated dilatation of the afferent arteriole
4. DBlocks aldosterone receptors and so raises serum potassium
Answer and explanation in LearnFree account
Question 15 · Medium
Why is a proton pump inhibitor best taken 30 to 60 minutes before a meal?
1. AIt slows gastric emptying so the drug acts longer
2. BFood destroys the drug in the stomach before it can be absorbed
3. CIt prevents the drug from being metabolised in the liver
4. DPumps are active after food, and PPIs bind only active pumps
Answer and explanation in LearnFree account
Question 16 · Medium
Verapamil slows the ventricular rate in atrial fibrillation because AV nodal conduction depends mainly on:
1. AInward-rectifier potassium channels
2. BFast sodium channels
3. CChloride channels
4. DL-type calcium currents
Answer and explanation in LearnFree account
Question 17 · Medium
A patient with heart failure and reduced ejection fraction is given hydralazine with isosorbide dinitrate. Hydralazine reduces the work of the left ventricle mainly by lowering:
1. AAfterload, through arteriolar vasodilatation
2. BHeart rate, through AV node blockade
3. CPlasma volume, through natriuresis
4. DPreload, through venodilatation
Answer and explanation in LearnFree account
Question 18 · Medium
Metoclopramide speeds gastric emptying mainly by:
1. ABlocking muscarinic receptors in the gut wall, which slows contraction
2. BStimulating alpha-2 receptors on enteric neurones to raise tone
3. CBlocking D2 receptors, so more acetylcholine is released in the gut
4. DInhibiting acid secretion and so reducing the volume in the stomach
Answer and explanation in LearnFree account
Question 19 · Medium
A woman complains of tiredness, weight gain and cold intolerance. TSH is 18 mIU/L (normal 0.4 to 4) and free T4 is low. This pattern indicates:
1. ASecondary hypothyroidism from pituitary failure
2. BPrimary hyperthyroidism
3. CPrimary hypothyroidism
4. DNormal thyroid function
Answer and explanation in LearnFree account
Question 20 · Medium
A man with polyuria has urine osmolality 150 mOsm/kg after water deprivation, rising to 620 after desmopressin. The diagnosis is:
1. ANephrogenic diabetes insipidus
2. BSIADH
3. CPrimary polydipsia
4. DCentral diabetes insipidus
Answer and explanation in LearnFree account
Question 21 · Easy
Furosemide produces diuresis mainly by inhibiting the Na-K-2Cl cotransporter in which segment?
1. AProximal convoluted tubule near the glomerulus
2. BDistal convoluted tubule
3. CThick ascending limb of the loop of Henle
4. DCortical collecting duct
Answer and explanation in LearnFree account
Question 22 · Medium
Sacubitril in sacubitril-valsartan helps in heart failure by inhibiting neprilysin, which raises levels of:
1. AAngiotensin II
2. BRenin
3. CNatriuretic peptides
4. DAldosterone
Answer and explanation in LearnFree account
Question 23 · Hard
A patient taking digoxin and furosemide has nausea, visual disturbances and a potassium of 2.8 mmol/L. Why does hypokalaemia increase digoxin toxicity?
1. APotassium and digoxin compete at the Na-K ATPase, so low potassium raises binding
2. BHypokalaemia increases digoxin absorption from the small intestine
3. CHypokalaemia reduces renal excretion of digoxin, so blood levels rise
4. DHypokalaemia slows CYP3A4 metabolism of digoxin so levels build up in plasma
Answer and explanation in LearnFree account
Question 24 · Hard
A patient with low albumin has total calcium 2.00 mmol/L and albumin 25 g/L. Using the correction of 0.02 mmol/L for each g/L that albumin is below 40, the corrected calcium is:
1. A2.15 mmol/L
2. B2.60 mmol/L
3. C2.30 mmol/L
4. D1.70 mmol/L
Answer and explanation in LearnFree account
Question 25 · Hard
A woman stops prednisolone 15 mg daily after 6 months and is admitted with hypotension and hypoglycaemia. Which electrolyte finding is expected in this secondary adrenal insufficiency?
1. AA normal potassium, because aldosterone secretion is preserved
2. BHypokalaemia from aldosterone excess
3. CHypercalcaemia from PTH deficiency
4. DMarked hyperkalaemia from aldosterone deficiency
Answer and explanation in LearnFree account

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Physiology and pathophysiology

Long-term acetazolamide commonly causes which acid-base change?

Palpitations after the first dose of immediate-release nifedipine are best explained by:

A patient with chronic kidney disease takes ramipril and spironolactone, and the potassium is 6.1 mmol/L. Which mechanism of spironolactone contributes most?

Omeprazole acts by inhibiting the H+/K+ ATPase pump in which cells?

A patient with COPD has pH 7.34, PaCO2 70 mmHg and HCO3 36 mmol/L. For every 10 mmHg rise in PaCO2, the chronic compensation is a rise in HCO3 of about 3.5 mmol/L. The best interpretation is:

Colestyramine reduces plasma LDL cholesterol mainly through:

Stimulation of cardiac beta-1 receptors increases heart rate and contractility through which signalling pathway?

A man has a glomerular filtration rate of 90 mL/min and a renal plasma flow of 450 mL/min. His filtration fraction is:

A patient has an end-diastolic volume of 140 mL, an end-systolic volume of 90 mL and a heart rate of 90 beats/min. What is the cardiac output?

Class I antiarrhythmic drugs such as flecainide slow conduction in the ventricle mainly by blocking which phase of the action potential?

Which part of the nephron reabsorbs the largest share (about two thirds) of filtered sodium and water?

Propranolol reduces the frequency of exertional angina mainly by lowering:

Constipation continues in a patient on long-term morphine because tolerance to this effect does not develop. The effect arises from:

A dehydrated patient on a loop diuretic takes ibuprofen and develops acute kidney injury. The main reason for this is that the NSAID:

Why is a proton pump inhibitor best taken 30 to 60 minutes before a meal?

Verapamil slows the ventricular rate in atrial fibrillation because AV nodal conduction depends mainly on:

A patient with heart failure and reduced ejection fraction is given hydralazine with isosorbide dinitrate. Hydralazine reduces the work of the left ventricle mainly by lowering:

Metoclopramide speeds gastric emptying mainly by:

A woman complains of tiredness, weight gain and cold intolerance. TSH is 18 mIU/L (normal 0.4 to 4) and free T4 is low. This pattern indicates:

A man with polyuria has urine osmolality 150 mOsm/kg after water deprivation, rising to 620 after desmopressin. The diagnosis is:

Furosemide produces diuresis mainly by inhibiting the Na-K-2Cl cotransporter in which segment?

Sacubitril in sacubitril-valsartan helps in heart failure by inhibiting neprilysin, which raises levels of:

A patient taking digoxin and furosemide has nausea, visual disturbances and a potassium of 2.8 mmol/L. Why does hypokalaemia increase digoxin toxicity?

A patient with low albumin has total calcium 2.00 mmol/L and albumin 25 g/L. Using the correction of 0.02 mmol/L for each g/L that albumin is below 40, the corrected calcium is:

A woman stops prednisolone 15 mg daily after 6 months and is admitted with hypotension and hypoglycaemia. Which electrolyte finding is expected in this secondary adrenal insufficiency?