Required Formulas Flashcards
1
Q
1 fl. oz
A
30 mL (approximately); 29.57 mL (actual)
2
Q
1 cup
A
8 oz., 240 mL (approximately); 236.56 mL (actual)
3
Q
1 pint
A
16 oz., 480 mL (approximately), 473 (actual)
4
Q
1 quart
A
2 pints, 960 mL (approximately), 946 mL (actual)
5
Q
1 gallon
A
4 quarts, 3840 mL (approximately), 3785 mL (actual)
6
Q
1 oz
A
28.4 g
7
Q
1 lb
A
454 g
8
Q
mEq to mmol
A
1:1 for monovalent ions, 1:0.5 for divalent ions
9
Q
1 inch
A
2.54 cm
10
Q
1 meter
A
100 cm
11
Q
% v/v
A
x mL/100 mL
12
Q
%w/w
A
x g/100 g
13
Q
Percentage strength
A
100/ratio strength
14
Q
Ratio strength
A
100/percentage strength
15
Q
PPM –> Percentage strength
A
Move the decimal left 4 places
16
Q
Percentage strength –> PPM
A
Move the decimal right 4 places
17
Q
Specific Gravity
A
weight of substance (g)/weight of equal volume (g) or g/mL
18
Q
Alligation
A
Check real flashcard
19
Q
Osmolarity
A
mOsmol/L = (wt of substance [g/L]/MW [g/mole]) x # of particles x 1000
20
Q
Isotonicity (E value)
A
E = 58.5i/(MW of drug x 1.8)
21
Q
Mols
A
g/MW
22
Q
mmols
A
mg/MW
23
Q
mEq
A
(mg x valence)/MW or mmols x valence
24
Q
Carbs and Protein Calories
A
4 kcal/gram
25
Fat calories
9 kcal/g
26
Dextrose monohydrate calories
3.4 kcal/gram
27
Amino acid solutions calories
4 kcal/gram
28
ILE 10% calories
1.1 kcal/g
29
ILE 20% calories
2 kcal/mL
30
ILE 30% calories
3 kcal/mL
31
Determining fluid needs
When weight > 20 kg: 1500 mL + (20 mL)(weight in kg - 20)
*can estimate using 30-40 mL/kg/day
32
Total Energy Expenditure
TEE = BEE x activity factor x stress factor
33
Grams of Nitrogen from Protein
Nitrogen (g) = protein intake (g)/6.25
34
Corrected Calcium for Albumin < 3.5
Ca (corrected) (mg/dL) = calcium (serum reported) + [(4.0 - albumin) x (0.8)]
35
BMI
weight (kg)/[height (m)]squared
or
(weight (lbs)/[height (inches)]squared) x 703
36
Adjusted body weight
IBW + 0.4 (TBW - IBW)
37
Which weight to use for drug dosing (mg/kg)?
- All drugs (if underweight) --> TBW
- Most drugs (if normal weight or obese) -> IBW
38
What are the exceptions for the weights to use for drug dosing?
- IBW: Acyclovir, aminophylline, levothyroxine, theophylline (normal weight, obese)
- AdjBW: aminoglycosides
39
What lab value indicates someone is dehydrated?
BUN: SCr > 20:1
40
What is the Cockcroft-Gault Equation?
CrCl (mL/min) = [(140 - age)/(72 x SCr)] x weight in kg x (0.85 if female)
41
What vitals are necessary to determine arterial blood gas?
pH, pCO2, pO2, HCO3, O2
42
What are the steps to determine if someone is metabolic or respiratory and alkalosis or acidosis based on ABGs?
1) pH < 7.35 (acidosis), pH > 7.45 (alkalosis)
2a) Respiratory: pCO2 < 35 (alkalosis), pCO2 > 45 (acidosis)
2b) Metabolic: HCO3 > 26 (alkalosis), HCO3 < 22 (acidosis)
3) Which abnormal value (pCO2 or HCO3) matches the pH from Step # 1?
E.g. increased pH + increase pCO2 = respiratory acidosis
E.g. decreased pH + decreased HCO3 = metabolic acidosis
43
How do you calculate anion gap?
Anion gap (AG) = Na - Cl - HCO3
44
How do you calculate the pH of a weak acid?
pH = pKa + log [salt/acid]
45
How do you calculate the pH of a weak base?
pH = pKa + log [base/salt]
46
How do you calculate the percent ionization of a weak acid?
% ionization = 100/1 + 10^(pKa-pH)
47
How do you calculate percent ionization of a weak base?
% ionization = 100/1 + 10^(pH-pKa)
48
How do you calculate the absolute neutrophil count (ANC)?
ANC (cells/mm^3) = WBC x [(% segs + % bands)/100]
49
How do you convert from Fahrenheit to celsius?
Celsius = (Fahrenheit - 32)/1.8
50
How do you convert from celsius to fahrenheit?
Fahrenheit = (Celsius x 1.8) + 32
51
How do you calculate time to burn (TTB)?
TTB (with sunscreen in min) = SPF x TTB (without sunscreen)
52
How do you calculate risk?
Number of subjects in group with an unfavorable event/total number of subjects in group
53
How do you calculate relative risk?
RR = risk in treatment group/risk in control group
54
How do you calculate relative risk reduction?
RRR = (%risk in control group - %risk in treatment group)/%risk in control group
55
How do you calculate absolute risk reduction?
ARR = %risk in control group - %risk in treatment group
56
How do you calculate number needed to treat or number needed to harm?
NNT or NNH = 1/ARR*
*Expressed as decimal
57
How do you calculate odds ratio?
Refer to index card
58
How do you calculate hazard ratio?
HR = hazard rate in treatment group/hazard rate in control group
59
How do you calculate incremental cost-effectiveness ratio?
Incremental cost ratio = (C2 - C1)/(E2 - E1)
*C = costs, E = effects
60
How do you calculate pack-year smoking history?
Pack-year smoking history = cigarette packs/day x years smoked
61
What are the steps to initiating basal-bolus insulin in type 1 diabetes?
1) Calculate total daily dose (TDD) of 0.5 u/kg/day using TBW
2) Divide into 1/2 basal & 1/2 rapid-acting. If using NPH/R, use 2/3 & 1/3
3) Split rapid-acting among meals
62
How do you calculate insulin-to-carb ratio with the rule of 450 for regular insulin?
450/total daily dose of insulin = grams of carbohydrate covered by 1 unit of regular insulin
63
How do you calculate insulin-to-carb ratio with the rule of 500 for rapid-acting insulin?
500/total daily dose of insulin = grams of carbohydrate covered by 1 unit of rapid-acting insulin
64
How do you calculate correction factor with the rule of 1500 for regular insulin?
1500/total daily dose of insulin = correction factor for 1 unit of regular insulin
65
How do you calculate correction factor with the rule of 1800 for rapid-acting insulin?
1800/total daily dose of insulin = correction factor of 1 unit of rapid-acting insulin
66
How do you calculate a correction dose for hyperglycemia?
(blood glucose now - target blood glucose)/correction factor
67
How do you calculate LDL (Friedewald Equation)?
LDL = TC - HDL - TG/5
*do not use if TG > 400
68
How do you calculate minimum weighable quantity?
MWQ = sensitivity requirement/acceptable error rate (usually 0.05)
69
How do you calculate BSA?
BSA (m^2) = square root of [(Ht in cm x Wt in kg)/3600]
70
How do you calculate bioavailability?
F (%) = 100 x [AUC (extravascular)/AUC (intravenous)] x [Dose (intravenous)/Dose (extravascular)]
71
How do you calculate volume of distribution?
Vd = amount of drug in body/concentration of drug in plasma
72
How do you calculate clearance?
Cl = (F x dose)/AUC or ke x Vd
73
How do you calculate the elimination rate constant?
Ke = Cl/Vd
74
What formula can be used to predict drug concentration?
C2 = C1 x e^(-kt)
Ke = ln(C1/C2)/t
75
How do you calculate half-life?
T1/2 = 0.693/ke
76
How do you calculate loading dose?
LD = (desired concentration x VD)/F
77
How do you calculate mean arterial pressure?
MAP = [(2 x diastolic pressure) + systolic pressure]/3
78
How do you calculate phenytoin (total) correction for albumin < 3.5?
Phenytoin (corrected) (mcg/mL) = total phenytoin measured/[(0.2 x albumin) + 0.1]
79
What is KCl 10% oral solution equivalent to in tablets?
20 mEq/15 mL
80
How much elemental calcium is in calcium carbonate?
40%
81
How much elemental calcium is in calcium citrate?
21%
82
How do you convert Aminophylline dose to Theophylline dose?
Multiply by 0.8
*Remember ATM
83
How do you convert from Theophylline dose to Aminophylline dose?
Divide by 0.8
84
What are the equivalent doses of loop diuretics?
Ethacrynic acid 50 mg = Furosemide 40 mg = Torsemide 20 mg = Bumetanide 1 mg
85
What is the IV:PO conversion of loop diuretics? IV:PO conversion of Furosemide?
Furosemide IV:PO = 1:2
Other loops IV:PO = 1:1
86
What is the Metoprolol IV:PO conversion?
IV:PO = 1:2.5
87
How much elemental iron is in ferrous sulfate?
20% elemental iron
88
What is the conversion of insulin? What are exceptions to this rule?
Usually 1:1 conversion
Exceptions:
- NPH dosed BID = glargine dosed daily, use 80% of NPH
- Toujeo - other forms of glargine or detemir, use 80% of toujeo dose
89
What is the IV:PO Levothyroxine dose?
IV:PO = 0.75:1
90
What is the equivalent doses of steroids?
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
91
What is the equivalent doses of statins?
Pitavastatin 2 mg = Rosuvastatin 5 mg = Atorvastatin 10 mg = Simvastatin 20 mg = Lovastatin 40 mg = Pravastatin 40 mg = Fluvastatin 80 mg
92
What is the equivalent lithium content in lithium citrate syrup, lithium carbonate and Li ion?
5 mL lithium citrate syrup = 300 mg lithium carbonate = 8 mEq Li+ ion
