Required Formulas for Calculations

Question 1

1 quart = X mL

Answer 1

960 mL

Question 2

1 gallon = X mL

Answer 2

3,840 mL

Question 3

1 pound = X g

Answer 3

454 g

Question 4

1 grain = X mg

Answer 4

65 mg

Question 5

Specific Gravity equation

Answer 5

SG = g/mL

Question 6

PPM –> % strength

Answer 6

move decimal left 4 places

Question 7

% strength –> PPM

Answer 7

move decimal right 4 places

Question 8

Osmolarity equation

Answer 8

mOsm/L = [wt of substance (g/L)] / [MW (g/mole)] x (# of particles) x 1000

Question 9

Isotonicity equation (E value)

Answer 9

E = [(58.5 x i) / (MW of drug x 1.8)]

Question 10

moles equation

Answer 10

mols = g/MW

Question 11

mmols equation

Answer 11

mmols = mg/MW

Question 12

mEq equation

Answer 12

mEq = [ (mg x valence) / MW ] or

mEq = mmols x valence

Question 13

Enteral Nutrition Calories

Answer 13

Carbs/Protein = 4 kcal/g
Fat = 9 kcal/g

Question 14

Parenteral Nutrition Calories

Answer 14

Dextrosee monohydrate = 3.4 kcal/g
Amino acid solutions = 4 kcal/g 
ILE 10% = 1.1 kcal/mL
ILE 20% = 2 kcal/mL
ILE 30% = 3 kcal/mL

Question 15

Ideal Body Weight equation

Answer 15

IBW.m = 50 kg + 2.3 (>5’)

IBW.f = 45.5 kg + 2.3 (>5’)

Question 16

Adjusted Body Weight equation

Answer 16

AdjBW = IBW + 0.4(TBW - IBW)

Question 17

Which drugs uses IBW for drug dosing?

Answer 17

Aminophylline, Theophylline, Acyclovir & Levothyroxine

Question 18

Which drugs uses TBW for drug dosing?

Answer 18

LMWH, UFH, and Vancomycin

Question 19

Which drug uses AdjBW when patients are obese?

Answer 19

Aminoglycosides

Question 20

Labs that determines dehydration

Answer 20

BUN:SCR > 20:1

Question 21

ABG: pH/pCO2/pO2/HCO3/O2 sat

Answer 21

pH < 7.35 = alkalosis | pH > 7.45 = acidosis

Respiratory: pCO2 < 35 = alk | > 45 = acidosis

Metabolic: HCO3 > 26 = alk | < 22 = acidosis

if both pCO2 and HCO3 are abnormal; use the one that matches pH

Question 22

Anion Gap equation

Answer 22

AG = Na - Cl - HCO3

Question 23

Weak acid equation

Answer 23

pH = pKa + log [salt/acid]

Question 24

Weak base equation

Answer 24

pH = pKw - pKb + log [base/salt]

Question 25

Temperature Conversion; C --> F

Answer 25

C = (F - 32) / 1.8

Question 26

Temperature Conversion: F --> C

Answer 26

F = (C x 1.8) + 32

Question 27

Absolute Neutrophil Count

Answer 27

ANC = WBC x [ (segs % + bands %) / 100] **segs% or PMN or polys**

Question 28

Risk equation

Answer 28

Risk = [# of subjects in group with an unfavorable event] / [total # of subjects in group]

Question 29

Relative Risk equation

Answer 29

RR = [Risk in treatment group] / [Risk in contol group]

Question 30

Relative Risk Reduction equation

Answer 30

RRR = [ (% risk in control group - % risk in treatment group) / (% risk in control group) ]

Question 31

Absolute Risk Reduction equation

Answer 31

ARR = (% risk in control group) - (% risk in treatment group)

Question 32

Number Needed to Treat or Harm equation

Answer 32

NNT or NNH = 1 / ARR

Question 33

Odds Ratio equation

Answer 33

OR = AD / BC Exposure - Outcome Present - Outcome Absent Present A B Absent C D

Question 34

Hazard Ratio equation

Answer 34

HR = [Hazard rate in the treatment group] / [Hazard rate in the control group]

Question 35

Incremental Cost-Effectiveness Ratio equation

Answer 35

ICR = (C2 - C1) / (E2 - E1) C = costs; E = effects

Question 36

Pack-Year Smoking History

Answer 36

Pack-Year Smoking History = [Cigarette pack / day] x years smoked

Question 37

Friedewald Equation for Dyslipidemia

Answer 37

LDL = TC - HDL - [TG* / 5] *do not use if TG > 400

Question 38

Volume of Distribution equation

Answer 38

Vd = [amount of drug in body] / [conc of drug in plasma]

Question 39

Clearance equation *PK*

Answer 39

Cl = [F x dose] / AUC or Cl = ke x Vd

Question 40

Elimination Rate Constant (ke)

Answer 40

ke = Cl / Vd

Question 41

Half-life equation

Answer 41

t(1/2) = 0.693 / ke

Question 42

Loading Dose equation *PK*

Answer 42

LD = [desired conc x Vd] / F

Question 43

Bioavailability (F) equation

Answer 43

F (%) = 100 x [AUC extra / AUC intra] x [Dose IV / Dose EV]

Question 44

Prediction Drug Concentration equation

Answer 44

C2 = C1 x e^-kt ke = [ln (C1/C2) / t]

Question 45

KCL solution oral to tablets

Answer 45

KCl 10% = 20 mEq/15 mL

Question 46

Calcium Salts conversion

Answer 46

Calcium Carbonate = 40 % elemental calcium | Calcium Citrate = 21 % elemental calcium

Question 47

Aminophyllin to Theophylline conversion

Answer 47

ATM: A = T x 0.8 **T = A / 0.8

Question 48

Loop Diuretic Conversions

Answer 48

Ethacrynic acid 50 mg = Furosemide 40 mg = Torsemide 20 mg = Bumetanide 1 mg Furosemide IV:PO = 1:2 Other Loops IV:PO = 1:1

Question 49

Metoprolol IV:PO

Answer 49

1:2.5

Question 50

Ferrous Sulfate conversion

Answer 50

Ferrous Sulfate = 20 % elemental iron (325 mg x 20% = 65 mg iron)

Question 51

Levothyroxine IV:PO

Answer 51

0.75:1

Question 52

Steroids Conversions

Answer 52

``` Cortisone 25 mg Hydrocortisone 20 mg Prednisone 5 mg Prednisolone 5 mg Methylprednisolone 4 mg Triamcinolone 4 mg Dexamethasone 0.75 mg Betamethasone 0.6 mg ```

Question 53

Statin Conversions

Answer 53

``` Pitavastatin 2 mg Rosuvastatin 5 mg Atorvastatin 10 mg Simvastatin 20 mg Lovastatin 40 mg Pravastatin 40 mg Fluvastatin 80 mg ```

Question 54

Lithium Conversions

Answer 54

5 mL lithium citrate syrup = 300mg lithium carbonate = 8 mEq Li* ion