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Flashcards in NAPLEX math Deck (85):
1

1 tsp

5 mL

2

1 tbsp

15 mL

3

1 fl oz

30 mL

4

1 cup

8 oz / 240 mL

5

1 pint

2 cups / 16 oz / 480 mL

6

1 quart

2 pints / 4 cups / 28 oz / 960 mL

7

1 gallon

4 quarts / 8 pints / 16 cups / 128 oz / 3840 mL

8

1 kg

2.2 lb

9

1 oz

28.4 g

10

1 lb

454 g

11

1 grain

65 mg

12

1 inch

2.54 cm

13

aminophylline --> theophylline conversion

divide by 0.8

14

% w/v

g / 100 mL

15

% v/v

mL / 100 mL

16

% w/w

g / 100g

17

% strength

100 / ratio strength

18

ratio strength

100 / % strength

19

convert PPM --> % strength

move decimal LEFT 4 places

20

specific gravity

wt. of substance / wt of equal vol. H2O

21

equation for dilution/concentration

Q1 x C1 = Q2 x C2

22

mOsm/L

[wt of substance (g/L) / MW (g/mol)] x # particles x 1000

23

NaCl Equivalent (E)

(58.5 x i) / (MW x 1.8)

24

isotonicity problems

1. calc NaCl total needed (0.9% x desired vol.)

2. Multiply the total drug amount (in milligrams or grams) by E value

3. Subtract step 2 from step 1 to determine the total amount of NaCl needed to prepare an isotonic prescription

25

mol

g / MW

26

mEq

mmol x valence

OR

(mg x valence)/MW

27

KCl 10%

20mEq / 15 mL

28

BMI

weight (kg) / [height (m)]2

29

IBW (men)

50 + 2.3 (in > 5 ft)

30

IBW (female)

45.5 + 2.3 (in > 5 ft)

31

adjusted body weight

IBW + 0.4(TBW - IBW)

32

wt. based drug dosing

underweight: TBW always

Normal weight: Use TBW to dose most medications

use IBW for aminophyline, theophylline and acyclovir

Obese: (120-130% of IBW): 

  • use TBW for LMWHs, UFH, vancomycin
  • IBW for aminophylline, theophylline, acyclovir
  • AdjBW for aminoglycosides

33

dehydration

BUN:Scr ratio > 20:1

34

CrCl

[(140 - age) / (72 x Scr)] x wt (kg) x .85 (female)

35

Weights to use for CrCl

underweight: TBW

Normal weight: use IBW

Overweight (BMI >/= 25): use AdjBW

36

carb calories

4 kcal / g

37

dextrose calories in PN

3.4 kcal / g

38

glycerol calories in PN

4.3 kcal / g

39

fat calories

9 kcal / g

40

Fat PN calories (kcal / mL)

10% - 1.1 kcal / mL

20% - 2 kcal/mL

30% - 3 kcal/mL

41

protein calories

4 kcal / g

42

fluid needs

When weight > 20kg:

1500 mL + (20mL) (wt in kg - 20)

43

TEE

(total energy expenditure)

BEE x activity factor x stress factor

BEE = basal energy expenditure

44

calculating PN protein calories

non-stressed: 0.8 - 1 g/kg/day

hospitalized or malnourished: 1.2 - 2 g/kg/day

45

nitrogen intake

grams of protein / 6.25

46

NPC:Nitrogen ratio

(non-protein calories)

80:1 most severe pt

100:1 severely stressed pt

150:1 unstressed pt

47

calculating NPC:Nitrogen Ratio

1. calc g Nitro/day

48

calculating PN dextrose calories

70 - 85% of NPC (non-protein calories)

do not exceed 4 mg/kg/min.

49

calculating PN lipid calories

15 - 30% NPC

50

Na+ for PN

23.4% used

contains 4 mEq/mL

51

corrected Ca+

Ca + [(4 - albumin) x .8]

* use corrected calcium when albumin < 3.5 g/dL

52

arterial blood gases (ABG)

pH/pCO2/pO2/HCO3/O2 sat

53

metabolic acidosis

low HCO3, low pH

54

metabolic aklalosis

high HCO3, high pH

55

respiratory acidosis

high pCO2, low pH

56

respiratory alkalosis

low pCO2, high pH

57

anion gap

Na - Cl - HCO3

58

gap acidosis

>12 mEq / L

59

pH > pKa

acid is more ionized and more of conjugate base is un-ionized

60

pH = pKa

ionized = unionized

61

pH < pKa

acid is more unionized and more of conjugat base is ionized

62

weak acid formula

pH = pKa + log [salt/acid]

63

weak bases

pH = pKa + log [base/salt]

64

% ionization (weak acid)

100 / [1+10(pKa - pH)]

65

% ionization (weak base)

100 / [1 + 10(pH - pKa)]

66

calcium carbonate

40% elemental calcium

67

calcium citrate

21% elemental calcium

68

calcium acetate

25% elemental calcium

69

Absolute Neutrophil Count

WBC x [(% seg + % bands) / 100]

70

Alligation

Making % concentration from 2 different % concentrations

A image thumb
71

i values (dissaociation factor)

Number of dissociated ions

1

2

3

4

5

1 = 1

2 = 1.8

3 = 2.6

4 = 3.4

5 = 4.2

 

72

mmol

mg/MW

73

valence numbers

number of paired electrons thta are holding the compound together

anything with big metals (Ca, Fe, and Mg) has valence of 2. Otherwise, everything has valence of 1

74

BMI Classifications

< 18.5 = underweight

18.5-24.9 = normal weight

25-29.9 = overweight

>/= 30 = obese

75

Harris-Benedict equation (Basal energy expenditure, or basal metabolic rate)

BEE (males): 66.47 + 13.75(weight in kg) + 5(height in cm) - 6.76(age in years)

BEE (females): 655.1 + 9.6(weight in kg) + 1.85(height in cm) - 4.68(age in years)

76

How to reduce risk of calcium-phosphate precipitate in TPN

1. Choose calcium gluconate over calcium chloride

2. add phosphate first (after dextrose and amino acids), followed by other PN components, agitate solution, then add calcium near the end

3. Calcium & Phosphate added together should not exceed 45 mEq/L

4. Maintain proper pH

77

What order to calculate sodium, potassium & phosphate for PN?

You will always need more potassium or sodium than phosphate, so calculate phosphate first.

78

arterial blood gas reference ranges

pH: 7.35-7.45

CO2: 35-45

HCO3: 22-26

79

F (absolute bioavailability)

100 x [(AUCextravascular/AUCintravanous)(Doseintravenous/Doseextravascular)]

 

AUC extra goes on top x Dose intra goes on top

AUC intra x dose extra

80

Equivalent dose in new dosage form

Amount absorbed from current dosage form/F of new dosage form

81

volume of distribution

Vd (in L) = amount of drug in body (in mg)/concentration of drug in plasma (in mg/L)

82

Clearance

Cl = Rate of elimination (Re)/Concentration

OR

F(Dose)/AUC

83

Ke

(elimination rate constant)

Ke = Cl/Vd

84

T1/2

Half-life

0.693/ke

85

Loading dose

LD = (desired concentration x Vd)/F