Capstone - Ex 1

Question 1

Pharmacodynamics

Answer 1

Mech of action

Question 2

Pharmacokinetics

Answer 2

Distribution and metabolism

Question 3

Potency vs Efficacy

Answer 3

Potency: amount of the drug req’d to produce a desired effect

Efficacy: measure of maximal effect

Question 4

Dissociation constant (Kd)

Answer 4

LOW Kd means a HIGH affinity –> more potent

HIGH Kd means a LOW affinity –> less potent

Question 5

Which is more important? Efficacy or potency

Answer 5

Efficacy!

A less potent drug with high efficacy will produce better results than a less efficacious drug with high potency

Question 6

Which is more potent and efficacious… morphine vs buprenorphine

Answer 6

Buprenorphine is more potent, but less efficacious (partial agonist)

Morphine is less potent, but more efficacious (full agonist)

Question 7

Agonists vs Antagonists

Answer 7

Agonists have an effect

Antagonists bind tot he receptor but have no effect (block effect of the agonist)

Question 8

Competitive vs Non-competitive Antagonists

Answer 8

Competitive: compete with agonists for the active site (shift DR curve to the right)

Noncompetitive: binds to active or allosteric site; decreases the maximal response of the agonist (shifts DR curve to the right and DOWN)

Question 9

Therapeutic Window

Answer 9

Range of doses that produce therapeutic response w/out causing any significant adverse effect in patients

Question 10

Therapeutic index

Answer 10

TI is a comparison of the amount of a drug that causes the therapeutic effect to the amount that causes toxicity

High TI - good!

Low TI - bad! only req small increase in dose to produce toxic effects

Question 11

Which drugs are best absorbed from stomach?

Answer 11

Lipid soluble drugs (alcohol!)

Weak acids (uncharged - aspirin)

Question 12

Effects of pH on drug absorption

Answer 12

Weak acids are absorbed from acidic environments (stomach, acidic urine)

Weak bases are absorbed from basic environments (small intestine, basic urine)

Question 13

1st Pass Effect

Answer 13

Drugs given orally are absorbed by the stomach & intestines –> portal circulation passes through the liver where these drugs may be metabolized and/or secreted before reaching systemic circulation

Question 14

Bioavailability

Answer 14

Fraction of drug that is absorbed and escapes first-pass elimination - drug that is able to have an active effect

Question 15

Central vs Peripheral Compartments

Answer 15

Central: well-perfused organs/tissue

Peripheral: poorly perfused (skin, mm, fat)

Question 16

What are the two main routes of drug elimination?

Answer 16

Metabolism - Liver

• Phase 1 (oxidation by cytochrome p450s)
• Phase 3 (conjugation)

Excretion - kidney & liver

• Kidney –> urine
• filtration: glomerulus
• secretion: proximal tubules, transporters
• Liver –> bile
• transporters
• may be reabsorbed from the gut

Question 17

What is drug clearance?

Answer 17

Volume of blood cleared by an organ per unit time

Question 18

Steady state for CRI (IV(

Answer 18

Increases in dosing rate lead to proportional increase in steady state plasma concentration

Question 19

Steady state for repeated doses

Answer 19

Approaches steady state after 4 half lives, but with fluctuations

• reached after about 4 half lives
• proportional to dosage and inversely proportional to dose interval

Question 20

Concentration-dependent Abx

Answer 20

Brief periods of high drug levels are preferred

Question 21

Time-dependent Abx

Answer 21

Long periods above a minimum level are preferred

Question 22

What is a loading dose?

Answer 22

Dose you give at start of treatment to quickly reach a steady-state concentrations

Question 23

What is ‘minimum inhibitory concentration (MIC)’ in regards to Abx?

Answer 23

MIC is the lowest concentration of an antimicrobial that will inhibit the visible growth of a microorganism after overnight incubation

Question 24

Receptor vs Non-receptor mediated Toxicity

Answer 24

Receptor-mediated: “overstimulation” of ‘normal’ receptors

Non-receptor mediated:
bind to many proteins, DNA

Question 25

How much liver damage is needed to overwhelm the liver’s metabolism of drugs?

Answer 25

> 80%

No routine test available to test liver metabolism of drugs

Question 26

What is the chemical restraint used for fish?

Answer 26

Tricaine methanesulfonate (MS-222)

Local anesthetic that blocks VG Na channels in both PNS and CNS

Question 27

Chemical restraints for amphibians?

Answer 27

Topical gel applied to skin

Question 28

In many birds and some reptiles, the ____ jugular v is larger than the other and is used preferentially

Answer 28

RIGHT

Question 29

What common anti-parasitic drug can kill Chelonians?

Answer 29

Ivermectin!