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Pharm Unit 1 > 1. Pharmacokinetics (Random stuff that is tough to memorize) > Flashcards

1. Pharmacokinetics (Random stuff that is tough to memorize) Flashcards

1
Q

Which drug did they give as the example of a drug that has it’s permeability increased as extracellular pH rises? Why?

A

Lidocaine

Basic, as increased pH pull of Hs –> becomes unionized –> able to diffuse better

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2
Q

Which drug did they give as the example of a drug that has a much higher concentration in gastric acid? Why is this important?

A

Cocaine, gets ionized in low pH & trapped in stomach

Have to test gastric secretions if suspect overdose cuz plasma level may be undetectable

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3
Q

Phase 1 metab includes?

A

oxidation, epoxidation, deakylation, dehalogenation, reduction, hydrolysis

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4
Q

Phase 2 metab includes?

A

Acetylation, sulfanation, glucaronidation, glutathionation

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5
Q

How does renal extraction work for polar drugs?

A

Most drugs filtered at glomerulus if not protein bound

Secreted at proximal tubule

Passively reabsorbed at distal tubule (due to being concentrated)

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6
Q

What drugs were given as examples of drugs that are secreted? What is it’s estimated clearance?

A

Penicilin & p-aminohippurate

600 mL/minute

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7
Q

What drug was given as the example of a drug that is filtered, but not secreted or reabsorbed? What is its estimated clearance?

A

Inulin

130 mL/minute

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8
Q

Generally speaking what processes involve first order kinetics? Zero order?

A

Small [substrate] relative to enzyme (enzyme is not saturated), filtration, renal secretion, diffusion & ion trapping

Only when have high [substrate] relative to enzyme (enzymes are saturated) –> as substrate levels get low 0 turns into 1st order

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9
Q

Why are most drugs eliminated by 1st order elimination?

A

Our enzymes have a high capacity

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10
Q

Which type of elimination is related to the concentration of the drug present?

A

1st Order

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11
Q

Which type of drug elimination is independent of drug concentration?

A

AKA constant no matter what

0 order

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12
Q

Which type of elimination has a half life independent of drug concentration?

A

1st order

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13
Q

Which type of elimination occurs at a constant fraction?

A

1st order

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14
Q

Which type of elimination occurs at a constant rate?

A

0 order

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15
Q

The elimination time is directly proportional to amount consumed in what type of elimination?

A

0 order

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16
Q

Drugs with zero order elimination?

A

Phenytoin
Ethanol
Salicylate

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17
Q

What is the plateau principle?

A

Says it will take 3-5 half lives for drug with first order elimination to get to steady state & that once at steady state it would take 3-5 half lives to be eliminated if doses were stopped

Does NOT state what the SS is, just how long to get there

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18
Q

How would the maintenance dose/IV infusion rate change for somebody that has 50% of normal renal function?

A

Maintenance/infusion would be 50% of what you would use for a normal person

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19
Q

Example given of a drug that has biphasic elimination? Why? Why is this important?

A

Gentamycin

multi-compartment

Stays in system longer than would expect of normal 1st order elim

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20
Q

What is the example given for a drug which stops being effective as it is moved to other compartments (rather than elimination)?

A

Thiopentin anesthesia

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21
Q

What is efficacy? Efficacy is dependent on what?

A

Max response (only dependent on # functioning receptors)

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22
Q

What is potency? What is it dependent on?

A

effect at a given dose (independent of # receptors, affinity intrinsic to receptor & drug)
• EC50 = [drug] for ½ of efficacy
• ED50 = dose for ½ of efficacy

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23
Q

How is the response vs. log[drug] curve changed if you theoretically make a drug more potent? What does this represent in a practical sense?

A

Shift sigmoidal curve to the L

Need a smaller dose to achieve the same effect

24
Q

What is the example given of a drug that has rebound sensitivity (supersensitivity) if therapy is stopped?

A

Propranalol

If stop, worse than when started cuz have made more receptors

25
Q

What is the difference between a dose response curve & a quantal dose response curve/histogram?

A

Individual vs. population

26
Q

Difference between quantal dose response curve & histogram?

A

Histogram includes only the individuals that responded to that dose

Curve includes everyone who responded to that dose + all the doses smaller than that

27
Q

How is the response vs. log[drug] curve changed if you theoretically make a G protein receptor undergo amplification (1 receptor activates multiple G proteins)? What does this mean?

A

Shifts curve to the L (more potent)

Not all receptors need to be occupied to get max effect (exception to rule)

28
Q

Why do some organs get more drug than others? Which get most & which get least?

A

Different levels of blood flow per g tissue

Most = Kidney & lung
Medium = heart, liver & brain
Least = skin, muscle & adipose
29
Q

Which drug is 99% bound to proteins in plasma? Why is this important?

A

valium

Higher chance of drug itneractions

30
Q

What is the name of the membrane transporter responsible for active efflux of drug?

A

P-glycoprotein

31
Q

Example(s) of Tyrosine Kinase Receptor(s)?

A

EGF receptor

32
Q

Example(s) of Cytokine Receptors?

A

Jak-Stat
GH
Leptin

33
Q

What does it mean if all of a radiolabeled oral drug is eventually found in urine?

[Practice problem from hand out]

A

Drug & metabolites are all absorbed (can’t assume 100% bioavailabilty because drug may have been broekn down into metabolites & then absorbed & excreted)

34
Q

For an oral drug, what are the steps to get from GI into systemic circulation?

A
  1. Drug has to get absorbed into intestine (otherwise just get excreted)
  2. During travel some drug gets metabilized by small amount of cytochrome p450 in the intestine wall = Pre-first pass
    3 . 1st pass effect
  3. Into systemic
35
Q

What does parenteral mean?

A

“not via GI”

IV, injections …

36
Q

Charged vs neutral for acid & base?

A

Acid is H donor –> goes from uncharged to - charged if in basic environment

Weak bases are H acceptors –> go from nuetral to + charged if in acidic enviroment

37
Q

Vd for different drugs & molecules?

A

See p18 of lecture 18

38
Q

How will iver or kidney disease effect Vd of a drug?

A

Less binding proteins –> increase Vd as moves into periphery

39
Q

Lower yield. Memorize the reactions for various forms of metabolism?

A

See lecture 3

40
Q

What type of metab is performed by flavine protein?

A

reduction

41
Q

What type of metab is performed by soluble enzymes?

A

hydrolysis of esters & amines

42
Q

What drugs are given as examples of drugs that can be affected by a person being a rapid or slow acetylator?

A

Isoniazid

Hydralazine

43
Q

Examples of ligand gated ion channels?

A

Ach
GABA
Serotonin
Glutamate

44
Q

Phosphoinositide pathway (a type of g protein)?

A

activation of phospholipase c (PLC) –> Phosphoinositide –> DAG & IP3

45
Q

Prostaglandin pathway (a type of G protein)?

A

Angiotensin –> activation of PLA2 –> membrane phospholipase –> arachadonic acid –> COX –> prostaglandin –> becomes extracellualr signal for another receptor –> Camp, Ca or PKC

46
Q

What is the main mechanism for receptor uncoupling & desensitization?

A

Phosphorylation of receptor

47
Q

What were the examples given as situations where desensitization can be present?

A

High beta adrenergic in heart failure (better to treat with beta antagonist than agonist, this is not intuitive)

Intentional desensitization for treatment with Lueprolide (–> lower testerone effects)

desensitization of leptin receptor –> obesity

48
Q

How does hyperthyroidism effect individuality of response to drugs?

A

thyroid hormone stimulates creation of beta receptor –> supersensitive to beta agonists

49
Q

Why do infants/newborns have different drug responses?

A

Different distribution due to body fat
Lower GFR
Less p450
Less plasma proteins

50
Q

Why do the elderly have different drug responses?

A 
Lower GFR (like peds)
Lower p450 (like peds)
Changes in PD
51
Q

How do ant-acids effect drugs?

A

Decreased absorption

52
Q

How does grape fruit juice or tropical fruits alter drug effects? Charbroiled meat, broccoli or sprouts?

A

Inhibit p450

Induce p450

53
Q

What habit induces p450? Effect of this?

A

Smoking, drugs & alcohol

Need higher doses cuz metab

54
Q

What drugs are given as examples of drugs that can inhibit drug transport?

A

Verapamil & digoxin

55
Q

What drug inhibits p450?

A

Warfarin

Pharm Unit 1 (7 decks)

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