4 Pharmacokinetics/dynamics

Question 1

Vd of a drug that is lipophilic v hydrophobic

Answer 1

Lipophilic= exceeds TBW >0.6L/kg. Hydrophilic= <0.6 L/kg

Question 2

Clearance is directly related to 3

Answer 2

Bf to clearing organ, extraction ratio, drug dose

Question 3

Clearance is inversely proportional to 2

Answer 3

Bf to clearing organ and drug conc in central compartment

Question 4

When is steady state achieved

Answer 4

5 half times

Question 5

Alpha phase

Answer 5

Central compartment (plasma) to peripheral (tissues).steep pt of slope, distribution,

Question 6

Beta phase

Answer 6

Elimination from central compartment

Question 7

Elim half life

Answer 7

Time for half of drug to be removed from body after IV injection

Question 8

Elim half time

Answer 8

Time for half of drug to be removed from plasma during elim phase

Question 9

Ionized: solubility, hepatic v renal elim, diff thru bbb/gi tract/placenta

Answer 9

Hydrophilic/lipophobic, renal elim, no diffusion

Question 10

Non ionized: solubility, hepatic v renal elim, diffusion

Answer 10

Lipophilic/hydrophobic, more hepatic, diffusion across bbb/gi/placenta

Question 11

How to tell if a drug is a weak acid

Answer 11

Usually w a positive ion like na, ca, or mg

Question 12

How to tell if a drug is a weak base

Answer 12

Usually with a neg ion like cl or so4

Question 13

When unionized fraction predominates

Answer 13

If molecule weak base and ph of sol > pka of drug. Or if its a weak acid and ph sol is

Question 14

How to calc % change w drugs

Answer 14

(New value - old value) / old value. X 100

Question 15

Albumin: carries ___ charge, binds ___ drugs mainly

Answer 15

Negative, acidic

Question 16

A1 glycoprotein binds ___ drugs, beta globulin binds ___ drugs

Answer 16

Basic, basic

Question 17

Conditions w dec albumin, effect

Answer 17

Decreased binding of acidic drugs: liver/renal disease, elderly, malnutrition, preg

Question 18

A1 glycoprotein effect when inc, cond, effect when dec, cond

Answer 18

Inc= more basic drug binding: stress, mi, pain, RA, elderly. Dec= less basic drug binding, preg and neonates

Question 19

Zero v first order kinetics

Answer 19

Zero= linear, constant amt per time. First order= log, constant fraction per time

Question 20

Drugs that follow zero order kinetics

Answer 20

Asa, phenytoin, alcohol, warfarin, heparin, theophylline

Question 21

Phase 1 reactions

Answer 21

Oxidation, reduction, hydrolysis

Question 22

Phase 2 rxn.

Answer 22

Conjugation, adding on a polar/h20 soluble substrate to molecule to allow it to be excreted

Question 23

Phase 3 metab

Answer 23

Elimination. ATP dep carrier proteins transport drugs across membranes in kidney, liver, and gi tract

Question 24

Drugs w low hepatic Er 7

Answer 24

Roc, valium, Ativan, methadone, tpl, theophylline, phenytoin

Question 25

Drugs w intermediate hepatic Er

Answer 25

Versed, vec, alfent, methohexital

Question 26

Drugs w high hepatic Er

Answer 26

Fent, sufent, morphine, demerol, narcan, ketamine, prop, lido, bup, metop/propranolol/Alpren, nifedipine, dilt, verap

Question 27

CYP 3A4: drug substrates affected by it

Answer 27

Opioids (fent, methadone), benzos, locals

Question 28

Cyp 3a4 inducers

Answer 28

Etoh, rifampin, barbs, tamoxifen, carbamazepine, john wort

Question 29

Cyp 3a4 inhib

Answer 29

Grapefruit juice, cimetidine, emycin, antifungals, ssris

Question 30

Cyp 2d6 substrates

Answer 30

Codeine to morphine, oxycodone, hydrocodone

Question 31

Cyp 2d6 inducers and inhib

Answer 31

Induce: disulfiram. Inhib: isoniazid, ssris, quinidine

Question 32

Dynamics v kinetics

Answer 32

Dynamics= effect site conc and clinical effect. Kinetics= drug dose and plasma conc

Question 33

Pharmacobiophasics

Answer 33

Plasma conc and effect site conc

Question 34

Dose response curve: x axis, y axis, slope

Answer 34

X= potency, y= efficacy, slope= receptors occupied to elicit a clinical effect

Question 35

Synergism v potentiation

Answer 35

Syn= 1+1= 3. Potentiation= 0+1=3. Pot= has one drug that enhances another drug that would’ve had no effect on its own

Question 36

How to calculate therapeutic index

Answer 36

LD50 / ED50

Question 37

Chirality

Answer 37

Carbon bonded to 4 diff atoms. 2 enantiomers

Question 38

Enantiomer

Answer 38

Chiral molecules that are mirror images

Question 39

Site with lowest bioavailability

Answer 39

Intrathecal

Question 40

Vessel rich: % co, % total body mass

Answer 40

75. 10