Naplex 2025 Required Formulas and drug dose conversions

Required formulas

Liquid volumes

1tsp = mL

1tbsp= mL

1 fl oz= mL

1 cup= mL and Oz

1 pint= mL and Oz

1 quart= mL and pints

1 gal =mL and quarts

Liquid volumes

1tsp = 5mL

1tbsp= 15mL

1 fl oz= 30mL

1 cup= 240mL and 8Oz

1 pint= 480mL and 16Oz

1 quart= 960mL and 2pints

1 gal =3,840mL and 4quarts

Solid weights

1kg = lbs

1oz = grams

1lbs = grams and oz

1 grain= mg

1kg = 2.2lbs

1oz = 28.4grams

1lbs = 454grams and 16oz

1 grain= 65mg

Height conversions

1in=cm

1meter = cm

1in=2.54cm

1meter=100cm

How do you convert a PPM to percentage strength?

How do you convert percentage strength to PPM?

Take PPM value and move the decimal 4 places to the left

Take the % Strength and move decimal 4 places to the right

What is the specific gravity formula?

Weight of substance / weight of equal volume of water. (AKA g/mL)

What formula is used for dilutional and concentration changes?

Q1C1=Q2C2

How to calculate an E value (aka isotonicity)

E= 58.5(i-value) / (MW of drug)(1.8)

Enteral nutrition kCal

carbs

protein

fat

Carbs = 4 kCal/g

Protein = 4kCal/g

Fat = 9 kCal/g

Parenteral nutrition kCal

Dextrose

Amino acid solutions

Lipid solutions (10%, 20%, 30%)

Carbs = 3.4 kCal/g,

Protein = 4 kCal/g,

10% lipid emulsion = 1.1 kCal/mL

20% lipid emulsion = 2.0 kCal/mL

30% lipid emulsion = 3.0 kCal/mL

Determining a patient’s fluid need when weight >20 kg?

How can you quickly estimate?

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

OR fast estimate 30-40mL/kg/day

Total energy expenditure (TEE)

TEE=BEE(activity factor)(Stress factor)

Grams of nitrogen from protein

Nitrogen (grams) = protein intake in grams/6.25

Corrected calcium for albumin <3.5 formula

serum Calcium + [(4-albumin)(0.8)]

BMI formula in metric and english units

1. kg/[height in m]²

2. 703 * lbs/[height in inches]²

IBW formula

AdjBW

IBW men: 50+ (2.3*inches over 5ft)

IBW women: 45.5+ (2.3*inches over 5ft)

AdjBW = IBW + (TBW-IBW)(0.4)

which weight to use for drug dosing

Underweight patients

Normal weight and obese

—acyclovir, aminophylline, synthroid, and theophylline—

—aminoglycosides—

Underweight: TBW

Most drugs (normal or obese): TBW

—IBW — acyclovir, aminophylline, synthroid, and theophylline

—AdjBW for aminoglycosides

What BUN:SCr ratio is indicative of dehydration

>20:1

Cock-croft-gault

(140-age)(weight)(0.85 if female)/(72*Scr)

ABG:

What are the following values in order x/x/x/x/x

What is a normal pH

What are the normal ranges for HCO3 and pCO2

pH/pCO2/pO2/HCO3/O2Sat

pH: 7.35-7.45

HCO3: 22-26

pCO2: 35-45

anion gap equation

Na-cl-HCO3

pH equations for

1. weak acid

2. weak base

1. Weak acid pH = pKa + log[salt/acid]

2. weak base pH = pKa + log[base/salt]

% ionization for weak acid and weak base

1. weak acid:

   100/(1+10^pka-pH)

2. Weak base:

   100/(1+10^pH-pKa)

ANC equation

WBC * (%segs+%bands)/100

Temperature conversion formulas`

C=(f-32)/1.8

F=(C*1.8)+32

Sunscreen time to burn equation

Time to burn with sunscreen = SPF*time to burn w/o sunscreen

What are the following?

Mean

Median

Mode

Mean: Average value

Median: Middle number of an ordered list

Mode: value that occurs most often

How do you calculate risk in stats?

Number of subjects in a group with an unfavorable outcome divided by total number of subjects in group

How do you calculate relative risk?

Risk in treatment group divided by risk in the control group

How do you calculate relative risk reduction

(%risk in control gorup-%risk in treatment group)/risk in control group

How do you calculate absolute risk reduction (ARR)

(%risk in control) - (%risk in the treatment group)

How do you calculate number needed to treat or number needed to harm

1/ARR in other words

1/(%risk in control - %risk in treatment group)

Hazard ratio equation

hazard rate in treatment group divided by hazard rate in the control group

what is the incremental cost-effectiveness ratio

(C2-C1)/(E2-E1)

C=costs E=effects

Tobacco cessation packs per year equation

packs per day x years smoked

How do you start insulin in a type 1 DM

1. TDD = 0.5 units/kg/day

2. half of TDD for basal and half for boluses

3. divide bolus units by 3 for meals

Equation for insulin to carb ratio for regular insulin

rule of 450

450/TDD = grams of carbs covered by 1 units of regular insulin

Equation for insulin to carb ratio for rapid acting insulin

Rule of 500

500/TDD = grams of carbs covered by 1 unit of rapid acting insulin

Equation for regular insulin correction factor

rule of 1500

1500/TDD = correction factor for 1 unit of regular insulin

Equation for rapid-acting insulin correction factor

Rule of 1800

1800/TDD = correction factor for 1 unit of rapid-acting insulin

What is the Friedewald equation for calculating LDL

When can’t you use it

LDL = TC-HDL- TG/5

(Don’t use if TG >400)

Equation for minimum weighable quantity

sensitivity requirement/acceptable error

(acceptable error is generally 0.05)

Body surface area equation

{[height (cm) x wt (kg)]/3600}^1/2

Bioavailability (F)

100 * AUC extravasular/AUC intravenous * dose intra/ dose extra

Vd equation

drug in the body/concentration of drug in the plasma

Clearance equations (2)

Cl=F*dose/auc

or Cl=ke*Vd

Elimination rate constant

ke = Cl/Vd

Predicting drug concentrations equations (2)

C2 = C1 + e^-kt

ke = [ln(c2/c1)]/t

half-life equation

t1/2 = 0.693/ke

LD equation

LD = (desired concentration*vd)/F

MAP equation

2/3 diastolic + 1/3systolic

Phenytoin correction equation for albumin <3.5

Total phenytoin measured/[(0.2*albumin)+0.1)]

10% KCl oral solution has how man mEq?

20mEq/15mL

How much elemental calcium are in the two salts

Calcium carbonate

Calcium citrate

Calcium carbonate = 40% elemental calcium

Calcium citrate = 21% elemental calcium

How do you convert aminophylline to theophylline? (ATM)

How do you convert theophylline to aminophylline?

Aminophylline*0.8

Theophylline/0.8

Equivalent statin strengths

Pitavastatin

Rosuvastatin

Atorvastatin

Simvastatin

Lovastatin

Pravastatin

Fluvastatin

Pitavastatin =2mg

Rosuvastatin = 5mg

Atorvastatin=10mg

Simvastatin=20mg

Lovastatin=40mg

Pravastatin=40mg

Fluvastatin=80mg

Metoprolol IV:PO

1:2.5

Equipotent Loop Diuretic doses (IV and PO)

Ethacrynic acid

Furosemide

Torsemide

Bumetanide

Ethacrynic acid: 50mg

Furosemide:40mg PO 20mg IV

Torsemide:20mg PO

Bumetanide: 1mg PO 1mg IV

Insulin coversions within the same class is usually 1:1

What adjustment is needed for NPD BID to daily glargine?

What adjustment is needed for Toujeo to other forms of glargine and detemir?

Use 80% of the NPH dose

Use 80% of the Toujeo dose

Levothyroxine IV:PO coversion

0.75:1

Steroid equivalent doses

Cortisone

Hydrocortisone

Prednisone

Prednisolone

Methylprednisolone

Triamcinolone

Dexamethasone

Betamethasone

Cortisone = 25mg

Hydrocortisone = 20mg

Prednisone = 5mg

Prednisolone = 5mg

Methylprednisolone = 4mg

Triamcinolone = 4mg

Dexamethasone = 0.75mg

Betamethasone = 0.6mg

Opioid equivalent doses (IV and PO)

Morphine

Hydromorphone

Oxycodone

hydrocodone

Codeine

Fentanyl

Meperidine

Oxymorphone

Drug IV PO

Morphine 10mg 30mg

Hydromorphone 1.5mg 7.5mg

Oxycodone - 20mg

Hydrocodone. - 30mg

Codeine 130mg 200mg

Fentanyl. 0.1mg -

Meperidine 75mg 300mg

Oxymorphone. 1mg 10mg

5mL of lithium citrate

• is equal to how many mg of lithium carbonate?

• is how many mEq of Lithium?

5mL of lithium citrate

= 300mg lithium carbonate

= 8 mEq lithium