1. A patient taking erythromycin develops an increased plasma concentration of warfarin, resulting in an elevated INR and bleeding risk. Which pharmacokinetic mechanism best explains this interaction?
A. Reduced gastrointestinal absorption
B. Inhibition of hepatic drug-metabolising enzymes
C. Induction of CYP3A4 enzymes
D. Increased renal tubular secretion
2. A weakly basic drug is formulated as an enteric-coated tablet. If the coating fails prematurely in the acidic environment of the stomach, what is the most likely formulation-related consequence?
A. Reduced drug ionisation and increased lipid solubility
B. Increased drug ionisation and possible reduced absorption
C. Immediate conversion of the drug into its active metabolite
D. Increased protection of the drug from gastric degradation
1 B
2 B
1.b
2.b
B,B
1.B
2.B