Required Formulas

1 tsp

5 mL

1 tbsp

15 mL

1 fl oz

30 mL

1 cup

8 oz or 240 mL

1 pint

16 oz or 480 mL

1 quart

2 pints or 960 mL

1 gallon

4 quarts or 3840 mL

1 kg

2.2 lbs

1 oz

28.4 g

1 lb

16 oz or 454 g

1 grain

65 mg

mEq to mmol for monovalent ions

1:1

mEq to mmol for divalent ions

1:0.5

1 inch

2.54 cm

1 meter

100 cm

% w/v

x g/100 mL

% v/v

x mL/100 mL

% w/w

x g/100 g

Ratio Strength to Percentage Strength

100/Ratio Strength

Percent Strength to Ratio Strength

100/Percent Strength

PPM to Percent Strength

Move the decimal left 4 places

Percent Strength to PPM

Move the decimal right 4 places

Specific Gravity

g/mL

Changing Strength or Quantity

Q1*C1=Q2*C2

Alligation

Larger Strength Top Left

Smaller Strength Bottom Left

Desired Strength Middle

Subtract diagonally to calculate parts required of each strength, then set proportion to calculate amount of each part

mOsmol/L (Osmolarity)

(Weight of Substance in g/L/MW in g/mol)*(# of particles)*1000

Number of Dissociation Particles

Dextrose, Mannitol: 1

KCl, NaCl, NaC2H3O2, MgSO4: 2

CaCl2: 3

Na3C6H5O7: 4

E (Isotonicity)

(58.5*i)/(MW of drug*1.8)

Dissociation Factor for Isotonicity

Increases by 0.8 for every additional dissociated ion (e.g., 1=1, 2=1.8, 3=2.6, 4=3.4, 5=4.2)

mols

g/MW

mmols

mg/MW

mEq

(mg*valence)/MW or mmols*valence

Valence Electrons for mEq Calculations

If compound starts with NH4, K, Na: 1

If compound starts with Ca, Fe, Li, Mg: 2

Calories of Carbohydrates in Enteral Nutrition

4 kcal/g

Calories of Protein in Enteral Nutrition

4 kcal/g

Calories of Fat in Enteral Nutrition

9 kcal/g

Calories of Dextrose in Parenteral Nutrition

3.4 kcal/g

Calories of Amino Acids (Protein) in Parenteral Nutrition

4 kcal/g

Calories of Injectable Lipid Emulsion (ILE) 10% in Parenteral Nutrition

1.1 kcal/mL

Calories of Injectable Lipid Emulsion (ILE) 20% in Parenteral Nutrition

2 kcal/mL

Calories of Injectable Lipid Emulsion (ILE) 30% in Parenteral Nutrition

3 kcal/mL

Maintenance Fluids

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

TEE (Total Energy Expenditure)

BEE*activity factor*stress factor

Activity Factor of Ambulatory (Out of Bed)

1.3

Activity Factor of Non-Ambulatory (Confined to Bed)

1.2

Nitrogen (g) for Grams of Nitrogen from Protein

Grams of Protein Intake/6.25

Corrected Calcium (Albumin < 3.5)

Reported Calcium + [(4-albumin)*0.8]

BMI

weight in kg/(height in m)²

IBW for males

50 kg + (2.3 kg)(number of inches over 5 feet)

IBW for females

45.5 kg + (2.3 kg)(number of inches over 5 feet)

AdjBW

IBW + 0.4*(TBW-IBW)

Use IBW

Acyclovir

Aminophylline

Levothyroxine

Theophylline

Use AdjBW

Aminoglycosides

drops/min

(drops/mL)(mL/hr)(hr/60 mins)

Dehydration

BUN:SCr > 20:1

CrCl (Cockcroft-Gault Equation)

[(140-age)(kg)]/[72*SCr] (*0.85 if female)

ABG Order

pH/pCO2/pO2/HCO3/O2 Sat

Metabolic Acidosis

pH < 7.35

HCO3 < 22

Metabolic Alkalosis

pH > 7.45

HCO3 > 26

Respiratory Acidosis

pH < 7.35

pCO2 > 45

Respiratory Alkalosis

pH > 7.45

pCO2 < 35

Anion Gap Equation

Na - Cl - HCO3

pH (Henderson-Hasselbalch Equation)

pKa + log(base/acid) or (14 - pKb) + log(base/acid)

% Ionization for Weak Acid

100/(1+10^(pKa-pH))

pH at the end of the exponent for weak acid

% Ionization for Weak Base

100/(1+10^(pH-pKa))

pKa at the end of the exponent for weak base

ANC

[WBC*(% segs + % bands)]/100

Fahrenheit to Celsius

(Fahrenheit - 32)/1.8

Celsius to Fahrenheit

(Celsius*1.8) + 32

TTB (Time To Burn) With Sunscreen (min)

SPF*TTB without sunscreen

Mean

Average Value

Median

Value in Middle of Ordered List

Mode

Value that Occurs Most Frequently

CI (Confidence Interval)

1-alpha, where alpha = probability of a type I error (false positive)

Risk

Number of subjects in group with an unfavorable event DIVIDED BY total number of subjects in that group

RR (Relative Risk)

risk in treatment/risk in control

Same as HR

RRR (Relative Risk Reduction)

1-RR or ARR/% risk in control

NNT (Number Needed to Treat)

1/ARR

Round Up

NNT (Number Needed to Treat)

1/ARR

Round Up

NNH (Number Needed to Harm)

1/ARR

Round Down

NNH (Number Needed to Harm)

1/ARR

Round Down

HR (Hazard Ratio)

risk in treatment/risk in control

Same as RR

ICER (Incremental Cost-Effectiveness Ratio)

(C2-C1)/(E2-E1)

Sensitivity (True Positive)

[TP/(TP+FN)]*100

Specificity (True Negative)

[(TN/TN+FP)]*100

Pack-Year Smoking History

(Cigarette Packs/Day)(Years Smoked)

Initiating Basal-Bolus Insulin in Type 1 Diabetes

1. Calculate TDD of 0.5 units/kg/day using TBW

2. Divide into ½ basal and ½ rapid-acting

3. Split rapid-acting among meals

Insulin-to-Carbohydrate Ratio for Regular Insulin

450/TDD of Insulin = grams of carbohydrates covered by 1 unit of regular insulin

Insulin-to-Carbohydrate Ratio for Rapid-Acting Insulin

500/TDD of Insulin = grams of carbohydrates covered by 1 unit of rapid-acting insulin

Correction Factor for Regular Insulin

1500/TDD of Insulin

Correction Factor for Rapid-Acting Insulin

1800/TDD of Insulin

Correction Dose

(Current BG - Target BG)/Correction Factor

LDL (Friedewald Equation)

TC - HDL - (TG/5)

Do NOT use if TG > 400

MWQ (Minimum Weighable Quantity)

Sensitivity Requirement/Acceptable Error Rate

Acceptable Error Rate is usually 0.05

BSA (m²) (Body Surface Area)

√(Height in cm)(Weight in kg)/3600

F (Bioavailability)

(AUC po/AUC iv)(Dose iv/Dose po)(100)

Vd (Volume of Distribution)

amount of drug in body/concentration of drug in plasma

Cl (Clearance)

ke*Vd or (F*dose)/AUC

ke (Elimination Rate Constant)

Cl/Vd or ln(C1/C2)/t

Predicting Drug Concentrations

C2=C1*e^-kt

C1 is the higher drug concentration

C2 is the lower drug concentration

t1/2 (Half-Life)

0.693/ke