Formula stuff Flashcards
Which weight do you use for all drugs when dosing if they are underweight?
Total body weight (TBW)
Which weight do you use for most drugs if they are normal weight or obese?
TBW
Which drugs do you use IBW for if they are normal or obese weight? What about AdjBW if they are obese what drug class?
IBW: Acyclovir, synthroid, aminophylline
AdjBW: Aminoglycosides
When weight is >20kg what is the formula for fluid needs?
1500mL + 20mL(weight in kg - 20)
What is 1 grain equal to
65 mg
what is specific gravity
g/mL
What is the normal ABG pH?
7.35-7.45
What defines respiratory and metabolic acid/alkolosis with pCO2 and HCO3?
Respiratory: pCO2 <35 alkalosis, pCO2 >45 acidosis
Metabolic: HCO3 > 26 alkalosis, HCO3 < 22 acidosis
How to calc anion gap?
Na - Cl - HCO3
ANC calculation
WBC x (%segs + % bands)/100
Risk equation
Risk = # of subjects in group with unfavorable event/ total # of subjects in group
Relative risk and RRR and ARR
RR= risk in treatment group/ risk in control group
RRR= (% risk in control group - % risk in treatment group) / % risk in control group
ARR= (% risk in control group - % risk in treatment group)
NNT
1/ARR as a decimal
Insulin to carb ratio for rapid acting
Rule of 500 for rapid acting insulin
500/TDD (total daily dose) = grams of carbs covered by 1 unit of rapid acting
Insulin to carb ratio for regular insulin
rule of 450
450/TDD= grams of carbs covered by 1 unit of reglular
Correction factor for rapid insulin and for regular insulin
Rapid: 1800/TDD= CF for 1 unit of rapid acting insulin
Regular: 1500/TDD= CF for 1 unit of regular
Correction Dose for insulin
CD= (BG now - BG target) / CF
Friedewald equation
LDL = TC - HDL - TG/5
Not valid when TG > 400
Minimum weighable quantity (MWQ)
Sensitivy requirement / 0.05 = MWQ
BSA
BSA= square root of [ Ht (cm) x Wt (kg) / 3600 ]
Bioavailability
F(%) = 100 x AUCextra / AUCintra x DOSEintra / DOSEextra
extravascular and intravascular
Volume of distribution
VD = Amount of drug in body / concentration of drug in plasma
Clearance
Cl = (F x Dose)/AUC
or
Cl=ke x Vd
Elimination rate constant
ke = Cl/Vd
Loading dose
LD = (Desired concentration x Vd) / F
Phenytoin total correction for albumin
albumin < 3.5
Phenytoin corrected (mcg/mL) = Total phenytoin measured / (0.2 x albumin) + 0.1
Can also do for valproic acid
KCl solution (oral) to tablets conversion
KCl 10% is what tablets
KCl 10% = 20 mEq/15 mL
Calcium salts what % elemental calcium
Carb and citrate
carbonate 40%
Citrate 21%
Aminophylline to Theophylline conversion
ATM (amin to theo multiple)
Amino to Theo x 0.8 so theo is stronger
Loop diuretic potency
Furosemide 40mg
Torsemide 20mg
Bumetanide 1 mg
All are 1:1 IV: PO except furosemide is 1:2 so double PO dose from IV
Metoprolol IV:PO conversion
1:2.5 IV:PO
Iron elemental %
Ferrous sulfate
20% elemental iron so 325mg x 0.2 has 65 mg iron
Insulin NPH dosed BID -> glargine dosed daily what is conversion?
Toujeo -> Lantus or Basaglar
NPH BID -> glargine QD (use 80% of NPH dose)
Toujeo -> Lantus/Basaglar (use 80% Toujeo dose)
synthroid IV:PO dose conversion
IV:PO 0.75:1
Steroid potency and equivalence
Cute Hot Pharmacists and Physicians Marry Together & Deliver Babies
Cortisone 25mg Methylprednisone 4mg
Hydrocortisone 20mg Triamcinolone 4mg
Prednisone 5mg Dexamethasone 0.75mg
Prednisolone 5mg Betamethasone 0.6mg
Statin equivalence
Pharmacists Rock At Saving Lives and Preventing Fatty-deposits
Pitavastatin 2mg Lovastatin 40mg
Rosuvastatin 5mg Pravastatin 40mg
Atorvastatin 10mg Fluvastatin 80mg
Simvastatin 20mg
Lithium conversions between syrup, mg, and mEq
5 mL = 300mg = 8 mEq
