Pharmacokinetics Equations

Question 1

IBW Female

Answer 1

45 + [2.3 x (height - 60)]

Question 2

IBW male

Answer 2

50 + [2.3 x (height-60)]

Question 3

Creatinine clearance (eGFR)

Answer 3

[(140-age) x IBW]/(72 x SCr)

Multiply by 0.85 if female

Question 4

Amount of dose absorbed

Answer 4

Amount of dose absorbed = (S)(F)(dose)

Question 5

Dose of different dosage form

Answer 5

Dose of different form = (amount absorbed from current form)/(S)(F) of new dosage form

Question 6

Plasma concentration (Cp)

Answer 6

Cp = (S)(F)(dose)/(Vd)

Question 7

Loading dose (LD)

Answer 7

LD = (Vd)(Cp)/(S)(F)

Question 8

Supplemental Loading Dose (LDsupp)

Answer 8

LDsupp = (Vd)(Cp desired - Cp initial)/(S)(F)

Question 9

Clearance (Cl)

Answer 9

Cl = (S)(F)(dose/tau)/Cp

Question 10

Maintenance dose (MD)

Answer 10

MD = (Cl)(Cp)(tau)/(S)(F)

Question 11

Elimination constant (Kel)

Answer 11

Kel = (Cl)/(Vd)

Kel = [ln(Cpt1) - ln(Cpt2)]/(t2-t1)

Question 12

Half life (t1/2)

Answer 12

t1/2 = 0.693/Kel

Question 13

Adjusted body weight

Answer 13

[0.4 x (ABW - IBW)] + IBW