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Flashcards in Pharm Deck (122):
1

Michaelis-Menten Kinetics
Equation
Vmax
Km
Curve

v = (Vmax[S])/(Km + [S])
Vmax directly proportional to enzyme concentration
Km inversely related to the affinity of the enzyme for its substrate
At 1/2 Vmax, Km=[S]
Hyperbolic

2

What kind of enzymatic reactions do not follow Michaelis-Menten Kinetics?

Enzymes that show cooperative kinetics (hemoglobin) have sigmoid curves

3

Lineweaver-Burk Plot
y axis
x axis
slope
y intercept
x intercept

1/V
1/[S]
Km/Vmax
1/Vmax. As y-intercept ↑, Vmax ↓
-1/Km. As x-intercept moves further to the right, ↑Km (lower affinity)

4

Lineweaver-Burk Plot
Competitive inhibitor
Noncompetitive inhibitor

Vmax stays the same as Km moves closer to the right. ↑Km (lower affinity)
y-intercept increases (↓Vmax) but Km (x-intercept) stays the same

5

Competitive Inhibitors
Resemblance to substrate
Over come by ↑[S]
Bind active site
Effect on Vmax
Effect on Km
Pharmacodynamics

Resemble substrate
Overcome by ↑[S]
Binds active site
Vmax unchanged
Km ↑
↓ potency

6

NonCompetitive Inhibitors
Resemblance to substrate
Over come by ↑[S]
Bind active site
Effect on Vmax
Effect on Km
Pharmacodynamics

No resemblance to substrate
Not overcome by ↑[S]
Doesn't binds active site
Vmax ↓
Km unchanged
↓ efficacy

7

Bioavailability
Variable
What is it?
When is it 100%

F
Fraction of administered dose that reaches systemic circulation unchanged
IV dose

8

Volume of distribution
Variable
What is it?
When can it be altered?
Equation

Vd
Theoretical fluid volume required to maintain the total absorbed drug amount at plasma concentration
Vd of plasma-protein bound drugs can be altered by liver and kidney disease (↓ protein binding, ↑ Vd)
(Amount of drug in body)/(plasma drug concentration)

9

Low Vd
Volume
Distribution
Drug types

4-8L
Blood
Large/charged molecules; plasma protein bound

10

Medium Vd
Distribution
Drug types

ECF
Small hydrophilic molecules

11

High Vd
Distribution
Drug types

All tissues
Small lipophilic molecules, especially if bound to tissue protein

12

A drug infused at a steady state takes how many half lives to reach steady state?

4 to 5

13

Half Life
Property of...
Equation

First Order Elimination
(.7Vd)/CL

14

Clearance
Variable
What is it?
Impaired with defect in what organ functions?
Equation (2)

CL
Relates rate of elimination to the plasma concentration
Impaired with defect in cardiac, hepatic, or renal function
(Rate of elimination)/(Plasma drug concentration) = Vd x Ke (elimination constant)

15

Loading dose

Cp x (Vd/F)
Cp = target plasma concentration

16

Maintenance dose

Cp x (CL/F)
Cp = target plasma concentration

17

What happens to loading dose and maintenance dose in liver or renal disease?

Loading dose remains the same
Maintenance dose ↓

18

Time to steady state depends primarily on

Half life
Independent of dosing frequency or size

19

Zero-Order Elimination
What is it?
How does Cp change?
Examples

Rate of elimination is constant regardless of Cp. Constant amount of drug eliminated per unit time
"PEA looks like a 0"
Phenytoin, EtOH, Aspirin (at high concentrations)

20

First-Order Elimination
What is it?
How does Cp change?
Description

Rate of elimination is directly proportional to the drug concentration. Constant fraction of drug eliminated per unit time
Cp ↓ exponentially with time
Flow-Dependent Elimination

21

Ionized vs non-Ionized species in the urine?
Weak Acids? What happens? Examples
Weak Bases? What happens? Examples

Ionized species trapped in the urine and cleared quickly. Neutral forms can be reabsorbed
Trapped in basic environments so treat OD with bicarb. Phenobarbital, Methotrexate, Aspirin
Trapped in acidic environments. Treat OD with Ammonium chloride. Amphetamines

22

Drug Metabolism Phase 1
Reactions
Mediator
Metabolites
Lost in what kind of pt

RedOx or hydrolysis
Cytochrome P450
Usually yields slightly polar water soluble metabolites (often still active)
Lost in geriatric pts

23

Drug Metabolism Phase 2
Reactions
Metabolites
Excretion
Decreased in what kind of pt

"GAS"
Conjugation (Glucuronidation, Acetylation, Sulfation)
Very polar inactive metabolites
Renally excreted
Slow acetylators

24

Efficacy
Definition
Examples

Maximal effect a drug can produce
Analgesics, Antibiotics, Decongestants

25

Potency
Definition
Mechanism
Examples

Amount of drug needed for a given effect
↑ potency --> ↑ receptor affinity
Chemotherapeutic drugs, AntiHTN, AntiLipid

26

Competitive Antagonist
Shifts effect vs dose curve?
Potency
Efficacy
How can it be overcome?
Examples

Shifts curve to Right
Potency ↓
No change in efficacy
↑ [agonist]
Diazepam and Flumazenil @ GABA Receptor

27

NonCompetitive Antagonist
Shifts effect vs dose curve?
Efficacy
How can it be overcome?
Examples

Shifts curve down
Efficacy ↓
Cannot be overcome by ↑ [agonist]
NE and Phenoxybenzamine @ α receptors

28

Partial Agonist
Where and how does it act?
Shifts effect vs dose curve?
Potency
Efficacy
Examples

Acts at same site as full agonist but with reduced maximal effect
Left shift at low concentrations but then levels off sooner and at lower concentration
Variable
Efficacy ↓
Buprenorphine @ μ

29

Therapeutic index
Measure of...
Formula
Safe drugs have what kind of TI?
Unsafe drug examples

Measure of drug safety
"TILE"
(Median Lethal dose)/(Median Effective dose)
Safer drugs have high TI
Low TI: Digoxin, Li, Theophylline, Warfarin

30

Therapeutic Window
Measure of what?
What is it?
Safe drugs have...

Measure of clinical drug safety
Range of minimum effective dose to minimum toxic dose
Safe drugs have large TW

31

Antidote for Salicylates

NaHCO3 (alkalinize urine), Dialysis

32

Antidote for Amphetamines

NH4Cl (acidify urine)

33

Antidote for AChE Inhibitors and Organophosphates

Atropine, Pralidoxime

34

Antidote for AntiMuscarinics and AntiCholinergics

Physostigmine Salicylate and Control Hyperthermia

35

Antidote for β blockers

Glucagon

36

Antidote for Digitalis

"stay "KALM"
Normalize K, Anti dig Fab Fragment, Lidocaine, Mg

37

Antidote for Fe?

DeFEroxamine, deFErasirox

38

Antidote for Pb

EDTA, Dimercaprol, Succimer, Penicillamine

39

Antidote for Hg, Arsenic, or Gold?

Dimercaprol, Succimer

40

Antidote for Cu, Arsenic, or Gold

Penicillamine

41

Antidote for Cyanide

Nitrite + Thiosulfate, Hydroxocobalamin

42

Antidote for Methemoglobin

Methylene Blue, VitC

43

Antidote for CO

100% O2, Hyperbaric O2

44

Antidote for Methanol, Ethylene Glycol

Fomepizole, EtOH, Dialysis

45

Antidote for Opioids

Naloxone, Naltrexone

46

Antidote for Benzodiazepines

Flumazenil

47

Antidote for TCAs

NaHCO3 (plasma alkalinization)

48

Antidote for Heparin

Protamine Sulfate

49

Antidote for Warfarin

VitK, Fresh Frozen Plasma

50

Antidote for tPA, Streptokinase, Urokinase

Aminocaproic Acid

51

Antidote for Theophylline

β blockers

52

Drugs that can cause Coronary Vasospasms

Cocaine, Sumatriptan, Ergot Alkaloids

53

Drugs that can cause Cutaneous Flushing

"VANC"
Vancomycin, Adenosine, Niacin, Ca channel blockers

54

Drugs that can cause Dilated Cardiomyopathy

Doxorubicin (Adriamycin), Daunorubicin

55

Drugs that can TdP

Class III (Sotalol) and Class IA (Quinidine)

56

Drugs that can cause Agranulocytosis

"Agranulocytosis Could Certainly Cause Pretty Major Damage"
Clozapine, Carbamazepine, Colchicine, Propylthiouracil, Methimazole, Dapsone

57

Drugs that can cause Aplastic Anemia

Chloramphenicol, Benzene, NSAIDs, Propylthiouracil, Methimazole

58

Drugs that can cause Direct Coombs + test

MethyDOPA, Penicillin

59

Drugs that can cause Gray Baby Syndrome

Chloramphenicol

60

Drugs that can cause Hemolysis in G6PD deficient pts

"Hemolysis IS PAIN"
Isoniazid, Sulfonamides, Primaquine, Aspirin, Ibuprofen, Nitrofurantoin

61

Drugs that can cause Megaloblastic Anemia

"Having a blast with PMS"
Phenytoin, Methotrexate, Sulfa drugs"

62

Drugs that cause thrombotic complications

OCP (estrogen)

63

Drugs that can cause Cough

ACEI

64

Drugs that can cause Pulmonary Fibrosis

"BLAB"
Bleomycin, Amiodarone, Busulfan

65

Drugs that can cause Acute Cholestatic Hepatitis, Jaundice

Erythromycin

66

Drugs that can cause Focal to Massive Hepatic Necrosis

"Liver HAVAc"
Halothane, Amanita Phalloides, Valproic Acid, Acetaminophen

67

Drugs that can cause Hepatitis

INH

68

Drugs that can cause Pseudomembranous Colitis

Clindamycin and Ampicillin

69

Drugs that can cause Adrenocortical Insufficiency

Steroids

70

Drugs that can cause Gynecomastia

"Some Drugs Create Awkward Enormous Knockers"
Spironolactone, Digitalis, Cimetidine, Alcohol, Estrogen, Ketoconazole

71

Drugs that can cause Hot Flashes

Tamoxifen, Clomiphene

72

Drugs that can cause Hyperglycemia

Niacin, Tacrolimus, Protease Inhibitors, HCTZ, Corticosteroids

73

Drugs that can cause Hypothyroidism

Li, Amiodarone, Sulfonamides

74

Drugs that can cause Fat redistribution

Steroids, Protease Inhibitors

75

Drugs that can cause Gingival Hyperplasia

Phenytoin, Verapamil

76

Drugs that can cause Gout

Furosemide, Thiazides, Niacin, Cyclosporine

77

Drugs that can cause Myopathies

"Fish N CHIPS Give you myopathies"
Fibrates, Niacin, Colchicine, Hydroxychloroquine, IFNα, Penacillamine, Statins, Glucocorticoids

78

Drugs that can cause Osteoporosis

Glucocorticoids, Heparin

79

Drugs that can cause Photosensitivity

"SAT for a photo"
Sulfonamides, Amiodarone, Tetracycline

80

Drugs that can cause Stevens-Johnsons Syndrome

"bad rash for a PEC SLAPP"
Penicillin, Ethosuximide, Carbamazepine, Sulfa drugs, Lamotrigine, Allopurinol, Phenytoin, Phenobarbital

81

Drugs that can cause SLE-like syndrome

"HIPP"
Hydralazine, INH, Procainamide, Phenytoin

82

Drugs that can cause Teeth in kids

Tetracyclines

83

Drugs that can cause Tendonitis, Tendon Rupture, or Cartilage Rupture

Fluoroquinolones

84

Drugs that can cause DI

Li, Demeclocycline

85

Drugs that can cause Fanconi's Syndrome

Expired Tetracycline

86

Drugs that can cause Hemorrhagic Cystitis

Cyclophosphamide, Ifosfamide
Prevented by Mesna

87

Drugs that can cause Interstitial Nephritis

Methicillin, NSAIDs, Furosemide

88

Drugs that can cause SIADH

Carbamazepine, Cyclophosphamide

89

Drugs that can cause Cinchonism

Quinidine, Quinine

90

Parkinsons-Like Syndrome

Antipsychotics, Reserpine, Metoclopramide

91

Drugs that can cause Seizures

"during seizures I BITE My tongue"
Isoniazid, Bupropion, Imepenem/cilastatin, Tramadol, Enflurane, Metoclopramide

92

Drugs that can cause Tardive Dyskinesia

Antipsychotics

93

Drugs that can cause Antimuscarinic effects

Atropine, TCAs, H1 blockers, Neuroleptics

94

Drugs that can cause Disulfiram-like reaction

Metronidazole, Cephalosporins, Procarbazine, 1st gen Sulfonylureas

95

Drugs that can cause Nephrotoxicity and Ototoxicity

Aminoglycosides, Vancomycin, Loop Diuretics, Cisplatin

96

P450 Inducers

"Momma Barb Steals Phen-phen and Refuses Greasy Carbs Chronically"
Modafinil, Barbiturates, St John's wort, Phenytoin, Rifampin, Griseofulvin, Carbamazepine, Chronic EtOH

97

P450 Inhibitors

"MAGIC RACKS in GQ"
Macrolides, Amiodarone, Grapefruit juice, Isoniazid, Cimetidine, Ritonavir, Acute EtOH abuse, Ciprofloxacin, Ketoconazole, Sulfonamides, Gemfibrozil, Quinidine

98

Sulfa Drugs

"Popular FACTSSS"
Probenecid, Furosemide, Acetazolamide, Celecoxib, Thiazides, Sulfonamide Antibiotics, Sulfasalazine, Sulfonylureas

99

Allergy to Sulf Drugs Presentation

Fever, UTI, Pruritic rash, Stevens-Johnson Syndrome, Hemolytic Anemia, Thrombocytopenia, Agranulocytosis, Urticaria

100

-azole

Antifungal

101

-cillin

Penicillin

102

-cycline

Antibiotic that inhibits protein synthesis

103

-navir

Protease Inhibitor

104

-triptan

5HT 1B/1D agonist

105

-ane

Inhalation general anesthetic

106

-caine

Local anesthetic

107

-operidol

Butyrophenone (neuroleptic)

108

-azine

Phenothiazine (antiemetic)

109

-barbital

Barbituate

110

-zolam

Benzodiazepine

111

-azepam

Benzodiazepine

112

-etine

SSRI

113

-ipramine

TCA

114

-triptyline

TCA

115

-olol

β antagonist

116

-terol

β2 agonist

117

-zosin

α1 antagonist

118

-oxin

Cardiac Glycoside

119

-pril

ACE Inhibitor

120

-afil

Erectile Dysfunction

121

-tropin

Pituitary Hormone

122

-tidine

H2 antagonist