NOTE: WRONG Answers on Multiple Choice Questions Will Result in The
BIMM118 – Midterm ’16
NOTE: WRONG answers on multiple choice questions will result in the
DEDUCTION of the points !!!!!
1) A competitive antagonist (5 pts ea)
a) binds to the same site on the receptor as the natural ligand
b) binds the receptor irreversibly
c) elicits a response from the receptor
d) shifts the dose-response curve to the right
e) shifts the dose-response curve to the right AND down
2) What is the LD50? (10 pts)
The dose that leads to the death of 50% of the test subjects
3) According to the diagram (5 pts each)
a) both drugs have the same efficacy
b) Drug B has higher efficacy
c) have different potency
d) Drug B has the lower potency
e) Drug A is a partial agonist
4) Which pharmacokinetic process is known as “First Pass Elimination”? (10 pts)
Drugs taken up in the intestine first reach the liver via the hepatic vein, and are therefore subject to hepatic metabolism prior to entering the general circulation.
5) Controlled substances are assigned to specific drug schedules. What are the basic substance properties that determine to which schedule a particular substance is assigned? (5 pts each)
a) Toxicity
b) Scientific evidence of medicinal efficacy
c) Cost of development
d) Risk of addiction
e) Risk of drug/drug interaction
f) Bioavailibility
6) Which of the following modifications will increase hydrophilicity of a drug? (5 pts ea)
a) glucoronidation
b) hydroxylation
c) sulfation
d) halogenation
e) alkylation
f) dealkylation
7) Administration of cyclooxygenase inhibitors (e.g. aspirin) can trigger asthma attacks in susceptible patients. Why? (10 pts)
By inhibiting COX, all available arachidonic acid is subject to conversion into leukotrienes by lipoxygenase. LT are potent bronchial constrictors, leading to asthma attacks.
8) When a loading dose is administered, the initial drug concentration is dependent on which of the following? (5 pts ea)
a) elimination rate constant
b) drug half-life
c) volume of distribution
d) clearance
e) metabolism
f) amount of drug administered
9) What is pharmacogenomics? Provide an example for its significance! (10 pts each)
Pharmacogenomics/pharmacogenetics: Field of pharmacology that deals with the variation in responses to drugs due to genetic dissimilarities.
*) CYP2C19 Polymorphism affects the ability of the enzyme to metabolize mephenytoin.
*) CYP2D6 Polymorphism: Defect in demethylation of codein (6-10% of Caucasians)
*) Polymorphism in alcohol- or aldehyde-dehydrogenase => defects in ethanol metabolism (“Asian Flush”)
10) What are the Vd and t1/2? How are they interconnected (explain the underlying concept!)? (10 pts)
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.
11) An older man is admitted to the emergency room with severe hypotensive crisis. In his pocket the staff finds a vial of Viagra, and, upon further examination, they notice a nitroglycerol transdermal delivery system (“patch”) on his chest. What is likely to have caused the symptoms? Justify your conclusion! (15 pts)
The patch is likely a nitrate delivery system to treat angina pectoris. The nitrates yield NO in the blood, which triggers cGMP production in the smooth muscle cells, causing relaxation of the smooth muscle cells and dilation of the blood vessels. Sildenafil (Viagra) inhibits PDE V, the enzyme mainly responsible for cGMP degradation, and as such further increases cGMP levels => excessive vasodilation => hypotensive crisis
12) Glucocorticoids display a slow onset of action, but their effect persists after the drug has cleared the body. Why? (15 pts)
Glucocorticoids mediate their actions through transcriptional responses via nuclear receptors. This delays the onset of their actions as transcription and translation events are involved, however, the newly induced proteins will still be present after the drug have cleared the body.
13) How does a matrix tablet differ from a coated tablet? How does the difference affect the release of the active ingredient (draw a basic diagram: x-axis=time; y-axis=drug concentration in plasma? (15 pts)
Coated tablet: Polymer covers a “classical” tablet (mostly made up of fillers); once coating is dissolved, the tablet quickly disintegrates and the active ingredient is released quickly.
Matrix tablet: Polymers makes up the tablet; active ingredient is evenly embedded in the tablet; tablet as the polymer dissolves, the active ingredient is released slowly.
14) Explain the difference between pharmacodynamics and pharmacokinetics!
(5 pts each)
Pharmacodynamics: What is the drug doing to the organism?
Pharmacokinetics: What is the organism doing to/with the drug (ADME)?
15) How would food that decrease the pH of the urine effect the excretion of a drug that is a weak base? Explain your conclusion! (10 pts)
An decrease in the pH of the urine implies that more of a drug that is a weak base exists in its ionized form in the urine. Increased ionization of the drug in the urine translates into increased accumulation of the drug in the urine=> increased excretion.