BIMM118 – Midterm ’08
NOTE: WRONG answers on multiple choice questions will result in the
DEDUCTION of the points !!!!!
1) A drug that is a partial agonist
a) binds to the same site on the receptor as the natural ligand
b) binds the receptor irreversibly
c) does not elicit a response from the receptor
d) shifts the dose-response curve of the natural ligand to the right
e) shifts the dose-response curve of the natural ligand to the right AND down
(5 pts each)
2) What are the Vd and t1/2? How are they interconnected (explain the underlying
concept!)?
Vd = volume of distribution; t1/2= half-life. Typically, drugs with a large Vd are highly
protein bound, and their metabolism/excretion is therefore attenuated. Consequently,
drugs with a large Vd have usually a longer half-life than drugs with small Vd.
(10 pts)
3) According to the diagram
a) Both drugs have the same efficacy
b) Drug B has higher efficacy
c) The drugs have different potency
d) Drug B has the lower potency
e) Drug A is a partial agonist
(5 pts each)
4) Provide an example of a food-drug interaction! Explain the underlying mechanism!
(10 pts)
*) Grapefruit juice contains a CYP3A4 inhibitor, thereby preventing oxidative metabolism of drugs
such as acetaminophen, codeine, warfarin, erythromycin etc.
*) MAO inhibitors (anti-depressant) also prevent the metabolism of tyramine, an amino acid found in
red wine and ripe cheeses. If not degraded by MAO, tyramine competes with (nor)epinephrine for
re-uptake and storage in presynaptic vesicles, thereby promoting sympathetic output.
