DHA Pharmacist Clinical Pharmacology 3

Question 1

What is the mechanism of action of proton pump inhibitors (PPIs) such as omeprazole?

Accepted Answer

Irreversible inhibition of the H⁺/K⁺-ATPase enzyme (proton pump) in gastric parietal cells

Answer

PPIs covalently and irreversibly bind to the H⁺/K⁺-ATPase proton pump in activated parietal cells, preventing acid secretion regardless of stimulant type.

Question 2

Why is warfarin dose adjustment required when a patient starts rifampicin therapy?

Accepted Answer

Rifampicin is a potent CYP2C9 inducer that increases warfarin metabolism, reducing its anticoagulant effect

Answer

Rifampicin strongly induces CYP2C9 and CYP3A4, accelerating warfarin metabolism and reducing its plasma levels, which can cause subtherapeutic anticoagulation and clot formation.

Question 3

What is the clinical importance of therapeutic drug monitoring (TDM) for vancomycin?

Accepted Answer

To ensure AUC/MIC targets are achieved for efficacy while avoiding nephrotoxicity

Answer

Vancomycin TDM using AUC/MIC-guided dosing balances optimal bactericidal exposure against nephrotoxicity risk, which is enhanced in critically ill or renally impaired patients.

Question 4

Which drug is used to reverse the anticoagulant effect of dabigatran (a direct thrombin inhibitor)?

Accepted Answer

Idarucizumab (Praxbind)

Answer

Idarucizumab is a humanised monoclonal antibody fragment that specifically and rapidly reverses dabigatran's anticoagulant effect by binding it with very high affinity.

Question 5

What is the pharmacological rationale for combining a beta-lactam with a beta-lactamase inhibitor (e.g., amoxicillin-clavulanate)?

Accepted Answer

The beta-lactamase inhibitor irreversibly binds and deactivates bacterial beta-lactamases, protecting the beta-lactam antibiotic from enzymatic degradation

Answer

Beta-lactamase inhibitors like clavulanate irreversibly inactivate bacterial beta-lactamases that would otherwise degrade the co-administered beta-lactam, restoring its antibacterial activity against resistant organisms.

DHA Pharmacist Practice Test

DHA Pharmacist Practice Test

DHA Pharmacist Clinical Pharmacology 3