1 pharm intro caldwell

Question 1

explain drug actions to a clinically relevant scenario for the following protein targets:
receptors
enzymes
carrier proteins
ion channels
structural proteins

Answer 1

Receptors –> can be agonist or antagonists w/ variable levels of binding

Enzymes –> can be inhibited (or rarely activated) ie. methotrexate binding DHFR enzyme

Carrier proteins –> inhibit normal activity ie. digitalis binding to NA/K ATPase pumps

Ion Channels –> binding can bring about opening or closing of channel

Structural proteins –> binding inhibits action ie. colchicine binds tubulin and inhibits mitosis

Question 2

Describe what is meant by a drug’s “Mechanism of Action”.

Answer 2

How a drug works. (includes site of action, mechanism and desired effects)

Question 3

Differentiate “pharmacodynamics” and “pharmacokinetics”.

Answer 3

Pharmacodynamics - actions of drug on body (desired effect, side effects)

Pharmacokinetics - actions of body on the drug (Absorption, Distribution, Metabolism, Elimination)

Question 4

Describe the difference between a “side-effect” and a “contraindication”.

Answer 4

Side effect –> adverse/undesired effect of drug

Contraindication –> Conditions/meds that precludes safe use of the drug

Question 5

Apply the three reasons to be careful using drugs in older patients in general to a clinically-relevant scenario.

Answer 5

reduced blood supply –> decreases absorption/distribution

reduced renal function –> decreases elimination

reduced liver function –> Decreases volume of distribution, plasma proteins, metabolism, elimination

Question 6

Describe how chirality (stereoisomerism) might affect the duration of a drug’s action.

Answer 6

chiral drugs with an asymmetric center will have enantiomers which may vary in all factors of pharmacokinetics and pharmacodynamics depending on the enantiomer. Many effects are very sterioselective.