PSA Drug Interactions 3

Question 1

A patient on ramipril is prescribed spironolactone for heart failure. What electrolyte abnormality is the primary concern?

Accepted Answer

Hyperkalemia from dual potassium-retaining mechanisms

Answer

Hypokalemia from combined natriuresis

Answer

Hyponatremia from combined diuretic effects

Answer

Hypercalcemia from altered calcium reabsorption

Question 2

Which drug combination carries the highest risk of serotonin syndrome?

Accepted Answer

SSRI with a monoamine oxidase inhibitor

Answer

SSRI with a beta-blocker

Answer

SSRI with a proton pump inhibitor

Answer

SSRI with a thiazide diuretic

Question 3

A patient on digoxin 125 mcg daily starts amiodarone for atrial fibrillation. Which mechanism best explains the increased digoxin toxicity risk?

Accepted Answer

Amiodarone inhibits P-glycoprotein, reducing renal and biliary digoxin elimination

Answer

Amiodarone induces renal CYP3A4, producing toxic digoxin metabolites

Answer

Amiodarone displaces digoxin from tissue binding sites, increasing free levels

Answer

Pharmacodynamic synergism at the Na+/K+-ATPase pump doubles the inotropic effect

Question 4

Which drug combination constitutes the renal 'triple whammy' associated with acute kidney injury?

Accepted Answer

NSAIDs + ACE inhibitors (or ARBs) + loop or thiazide diuretics

Answer

NSAIDs + ACE inhibitors + potassium-sparing diuretics

Answer

Aspirin + statins + beta-blockers

Answer

Metformin + ACE inhibitors + loop diuretics

Question 5

Which drug combination creates the greatest additive risk of QT prolongation and torsades de pointes?

Accepted Answer

Amiodarone and sotalol

Answer

Metformin and linagliptin

Answer

Amoxicillin and ibuprofen

Answer

Atorvastatin and ezetimibe

Question 6

Naloxone reverses opioid-induced respiratory depression via which interaction mechanism?

Accepted Answer

Competitive pharmacodynamic antagonism at mu-opioid receptors

Answer

Pharmacokinetic inhibition of CYP3A4-mediated opioid metabolism

Answer

Pharmaceutical incompatibility forming inactive opioid-naloxone complexes in blood

Answer

Allosteric modulation of the kappa-opioid receptor reducing opioid binding affinity

Question 7

A patient prescribed an opioid analgesic is also taking a benzodiazepine for anxiety. The most dangerous pharmacodynamic interaction produces:

Accepted Answer

Additive CNS and respiratory depression with risk of fatal apnea

Answer

Serotonin syndrome from combined monoamine effects

Answer

Neuroleptic malignant syndrome from dopaminergic disruption

Answer

QT prolongation from additive ion channel blockade