Intro to Pharmacology

Question 1

Pharmacodynamics

Answer 1

study of what drugs do to the body and study of quantification of drug responses. Can be very specific.

Question 2

Dose Response curves - variables

Answer 2

Use log scale for x - easier to see. x variable: Best to use conc. at target, but hard. Plasma conc (M, ng/mL) or dose (mg/kg, etc). Can be affected by tissues filtering or pharmcokinetic factors. y variable: therapeutic or toxic, can be graded (ie BP) or quantal (vomit/not, etc).

Question 3

Dose Response curves lines

Answer 3

response (y) is % max. show threshold of response and max. Linear basically from 15-85%.

Question 4

Drug potency

Answer 4

Dose-based index. It’s relative (no units). Smaller drug concentration producing 50% response Ex lower ED50. Generally higher potency is preferred.

Question 5

ED 50

Answer 5

conc. that produces 50% max. Low potency leads to higher dose, but can lead to toxicity

Question 6

Therapeutic index

Answer 6

ratio of toxic dose to effective (TD50 to ED50). Close to 1 = toxicities likely (chemotherapy). <10 = adverse effects likely. Greater than 10 is pretty safe (Over the counter drugs).

Question 7

Agonist

Answer 7

a drug that interacts with receptor, AND elicits a response via the receptor. Usually has a high efficacy, close to unity

Question 8

Antagonist

Answer 8

Drug that interacts with a receptor but does NOT stimulate or elicit transduction. Efficacy close to zero. Can prevent effect of an agonist. May elicit a response due to prevention of the action of an agonist

Question 9

Agonist and antagonist and curves

Answer 9

Full agonist: eff. of 1. Ant: eff. of 0, no direct response. Partial agonist/antag.: eff. between 0 and 1. Inverse agonist: eff. < 0, it stimulates receptor to do opposite of normal.

Question 10

Competitive antagonist

Answer 10

combines with same receptor as agonist. causes right shift on curve. can be overcome by high conc. of agonist.

Question 11

Irreversible antagonist

Answer 11

combines with same receptor as agonist. causes decrease of slope and max on curve. high conc. of agonist doesn’t help much.

Question 12

Other forms of antagonism

Answer 12

Block of receptor linkage: aka non-competitive antagonism. e.g., Ca2+ entry blockers inhibit positive inotropic agents. Physiological: agonist actions of two drugs work in opposite directions, e.g., nitroprusside in hypertensive crisis. Chemical: one drug neutralizes another, e.g., bicarbonate reduces gastric acidity. Pharmacokinetic: one drug binds to another to change its PK properties, e.g., cholestyramine binds digoxin to prevent absorption

Question 13

Targets of drugs

Answer 13

Membrane Receptors, Membrane Transporters, Membrane Ion Channels and Ion Exchangers, Multiple Types of Enzymes, Nuclear Receptors, Others