Medical Pharmacology Chapter 3: Pharmacodynamics Practice Questions

Drugs and their influence on metabolism:
1. Drug administration can result in increasing levels of drug-metabolizing enzymes by promoting expression of genes encoding for these enzymes.
2. Drug administration may result in a decrease of plasma drug concentration at receptor sites during drug treatment.
3. Both
4. Neither
Example/examples of (a) drug(s) acting at nuclear receptors and cause(s) an induction of drug metabolism.
1. Omeprazole
2. Fibrates
3. Rifampin
4. A & B
5. B & C
6. A & C
7. A, B & C
Atorvastatin (the drug ligand) interacts with the nuclear receptor (PXR). PXR interacts with another protein RXR in this complex binds to DNA. Following binding of the coactivator transcription is increased. PXR target genes include the cytochrome p450 isoform CYP3A4 which can metabolize atorvastatin.. Therefore atorvastatin administration activates its own metabolism.
1. True
2. False
A constituent of St. John's wort, hyperforin, is an activator of the PXR receptor (pregnane X receptor). As a result:
1. An increased failure of oral contraceptives in in those taking St. John's wort has been observed.
2. Activated PXR increases the levels of the cytochrome p450 isoform CYP3A4, metabolizing enzyme of steroids found in oral contraceptives.
3. Both
4. Neither
Activation of the AHR receptor(aryl hydrocarbon receptor) results in increased expression of genes that code for several cytochrome p450 isoforms. Metabolism by some of these isoforms result in metabolites which are chemical carcinogens.
1. True
2. False
Of the type 2 nuclear receptors in the same superfamily as steroid hormone receptors, some of these receptors are activated by drugs, as well as other exogenous agents. PXR, the pregnane X receptor,is activated by:
1. The synthetic steroid prednisolone-6A-carbonitrile.
2. Rifampicin
3. Troleandomycin
4. Nifedipine
5. Mevastatin
6. Troglitazone
7. Ritonavir
8. Paclitaxel
9. All of the above
Successful drug development depend(s) on:
1. Drug safety
2. Drug effectiveness
3. Both
4. Either
Metabolomics: toxicity biomarkers-a thorough identification quantification of metabolites. An example of high-throughput biomarker screening used in drug development.
1. True
2. False
Drug metabolism susceptible to genetic polymorphism may account (in part) for individual variation in responses to drugs:
1. Succinylcholine
2. Warfarin
3. Both
4. Neither
Patients exhibiting debrisoquine-sparteine oxidation polymorphism may require debrisoquine dosage adjustment.
1. True
2. False