Rx Math [➍] – Equations

Front 1

CONVERTING:

AMINOPHYLLINE

to

THEOPHYLLINE

Back 1

theophylline

is 80% of

aminophylline

Front 2

CONVERTING:

PERCENTAGE

to

RATIO STRENGTHS

Back 2

(g/100 mL) = (1 part) / (X parts)

Front 3

UNITS ﹠ CONVERSIONS:

Parts Per Million [PPM]

(𝒗𝓼)

Parts Per Billion [PPB]

Back 3

PPM = mg/L

PPB = mcg/L

Front 4

EQUATION:

Body Mass Index

[BMI]

(kg)

Back 4

Front 5

˹ ᶜˡᵃˢˢᶥᶠᶥᶜᵃᵗᶦᵒⁿˢ ˺

underweight = BMI of _____

normal wt = BMI of _____

overweight = BMI of _____

obese = BMI of _____

Back 5

Front 6

EQUATION:

Waist Circumference

for

Higher Risks

(inch)

Back 6

>35 inches for WOMEN

>40 inches for MEN

Front 7

EQUATION:

Ideal Body Weight

[IBW]

(kg)

Back 7

Front 8

EQUATION:

Cockcroft-Gault Equation

[CrCl]

(mL/min)

Back 8

Front 9

Renal Insufficient CLASSIFICATIONS:

MILD = CrCl _____ mL/min

MODERATE = CrCl _____ mL/min

SEVERE = CrCl _____ mL/min

Renal Failure = CrCl _____ mL/min

Back 9

MILD:

60 – 90

MODERATE:

30 – 59

SEVERE:

15 – 29

RENAL FAILURE:

<15 mL/min

or on DIALYSIS

Front 10

EQUATION:

Adjusted Body Weight

[AdjBW]

(kg)

Back 10

Front 11

If patient is:

UNDERWEIGHT = use _____ weight

NORMAL weight = use _____ weight

OVERWEIGHT = use _____ weight

Back 11

UNDERWEIGHT = use ACTUAL Body Weight

NORMAL weight = use IBW

OVERWEIGHT = use AdjBW

Front 12

EQUATION:

Specific Gravity [SG]

➊: SG of WATER = _____

➋: SG > 1 = _____

➌: SG < 1 = _____

Back 12

SG of WATER = 1;

[1g of WATER = 1mL of WATER]

SG > 1 = substance HEAVIER than water
SG < 1 = substance LIGHTER than water
SG does not have units

Front 13

EQUATION:

Body Surface Area

[BSA]

(m²)

Back 13

Front 14

EQUATION:

What are the

" ➌ Child Dosing "

equations?

Back 14

➊: Young's Rule

➋: Clark's Rule

➌: Adults BSA

Front 15

EQUATION:

ALLEGATION

(%)

Back 15

Front 16

EQUATION:

Half-Life

(t½)

Back 16

(t½) = 0.693 / ke

ke = elimination rate constant

Front 17

TPN EQUATION:

Determining Fluid Needs

Back 17

when WEIGHT > 20kg:

= 1,500 mL + (20 mL)(kg – 20)

[𝐍𝐑]: 30 – 40 mL/kg/D

Front 18

TPN EQUATION:

Basal Energy Expenditure

[BEE]

Back 18

BEE (males):

= 66.47 + 13.75(wt in kg) + 5.0(ht in cm) - 6.76(age in yrs)

BEE(females):

= 655.1 + 9.6(wt in kg) + 1.85(ht in cm) - 4.68(age in yrs)

These are resting energy requirements

Front 19

TPN EQUATION:

Total Energy Expenditure

[TEE]

Back 19

TEE = [BEE] ⊗ [ACTIVITY factor] ⊗ [STRESS factor]

Front 20

TPN EQUATION:

Nitrogen Balance

[NB]

Back 20

NB = (gm of PROTEIN intake) / 6.25

Front 21

TPN EQUATION:

Non-Protein Calories [NPC]

to

NITROGEN [N]

RATIO

Back 21

NPC:N ratios

80:1

the most severely stressed patients

100:1

severely stressed patients

150:1

unstressed patient

Front 22

EQUATION:

CORRECTED Ca²⁺

Back 22

Corrected Ca²⁺

= [Serum Ca²⁺] + (0.8)(4 – albumin)

Front 23

TPN EQUATION:

What are the ➍ STEPS

to reduce risk of

calcium-phosphate precipitate

in TPN?

Back 23

➊: Choose CALCIUM GLUCONATE over CALCIUM CHLORIDE

– due to being less reactive and lower risk of precipitation w/ PHOSPHATES

➋: Add PHOSPHATE first, then TPN, ﹠ then Ca²⁺ last

➌: Ca²⁺ & PHOSPHATE added together (same units) should not exceed 45 mEq/L

➍: Maintain proper pH, and keep in REFRIGERATOR

Front 24

EQUATION ﹠ CONVERSION:

TEMPERATURE

CONVERSION

Back 24

5F = 9C + 160

Front 25

EQUATION:

mOsmol/L

➌

Back 25

➋: mOsm = (MW / #Species) x (1/1,000)

➌: mOsmol/L = [GLU ÷ 18] + [BUN ÷ 2.8] + [(2)(Na+)}

Front 26

EQUATION:

ISOTONICITY

(E-value)

Back 26

Front 27

ISOTONICITY:

➌ STEPS for calculating

Isotonic Solutions (E-value)

with NaCl

Back 27

➊: Calculate NaCl needed to make final product isotonic:
0.9% NS should be multiplied by the desired volume for product.

➋: Multiply drug (in grams) by your E-value.

➌: Subtract Step 2 from Step 1 to determine total NaCl to make an isotonic product.

Front 28

UNITS ﹠ CONVERSIONS:

mols = _____

mmols = _____

Back 28

Moles (mols)

= grams / MW

Millimoles (mmols)

= mg / MW

Front 29

EQUATION:

mEq = _____

➋

Back 29

➊: mEq = [ mg x VALENCE ] / MW

➋: mEq = mmols / VALENCE

Front 30

EQUATION ﹠ CONVERSION:

TEMPERATURE

CONVERSION

Back 30

(5)℉ = (9)⁰C + 160

Front 31

Ca²⁺ CARBONATE ﹠ Ca²⁺ CITRATE:

Ca²⁺ carbonate = _____ % elemental Ca²⁺

Ca²⁺ citrate = _____ % elemental Ca²⁺

Back 31

CaCO₃= 40%

Acid-Dependent absorption;

should be TAKEN w/ FOOD

Ca₃[C₆H₅O₇]₂ = 21%

Acid-Independent absorption;

TAKEN w/ or w/o FOOD

Front 32

CBC ﹠ CBC w/ DIFFERENTIAL:

What are the

➒ COMPONENTS

of CBC?

Back 32

➊: WBC
➋: PLATELETS – (Plt)
➌: Hgb
➍: Hct
➎: RBC
➏: MCV
➐: MCH
➑: MCHC
➒: RDW

Front 33

EQUATION:

Absolute Neutrophil Count – [ANC]

/mm³

➋

Back 33

➊: ANC = WBC ⊗ (%segs + %bands)

➋: ANC = WBC ⊗ [(Segs + Bands) / 100]

Front 34

㉟: pH / ANION GAP / BUFFER:

Anion Gap

(mEq/L)

Back 34

ANION GAP = [Na⁽⁺⁾] – [Cl⁻ + HCO₃⁻]

AG > 12 mEq/L

indicates

GAP ACIDOSIS

Front 35

IONIZATION Equation

for

ACIDIC Drugs

vs

ALKALINE Drugs

Back 35

HA ⬌ [H⁺] + [A⁻]

BH⁺ ⬌ [H⁺] + [B]

Front 36

Henderson-Hasselbalch Equation

for

Weak ACID

➌

Back 36

➊: HA ⬌ [H⁺] + [A⁻]

➋: pH = pKa + log ([A⁻] / HA)

➌: pH = pka + log ([SALT] / [ACID])

Front 37

Henderson-Hasselbalch Equation

for

Weak BASE

➍

Back 37

➊: BH⁺ ⬌ [H⁺] + [B]

➋: pH = pKa + log ([B] / [BH⁺]

➌: pH = pKa + log ([BASE] / [SALT])

➍: pH = 14 – pKb + log ([BASE] / [SALT])

Front 38

EQUATION:

Minimum Weighable Quantity

[MWQ]

Back 38