Pharmacokinetics Equations

Question 1

Cockcroft Galt (eGFR)

Answer 1

EGFR = (140-age) * IBW/(72 * SCr) * 0.85 if female

Question 2

IBW

Answer 2

IBW = 0.45 + (2.3 * (height - 60 in) for female
IBW = 0.50 + (2.3 * (height - 60 in) for male

Question 3

Amount of drug absorbed

Answer 3

Amount of drug absorbed = S * F * Dose

Question 4

Dose of different dosage form

Answer 4

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

Question 5

Concentration plasma (Cp)

Answer 5

Cp = SFDose/Vd

Be sure to multiply Vd by IBW to get only mg

Question 6

Loading dose

Answer 6

LD = Cp * Vd/ S*F

Question 7

Supplemental loading dose

Answer 7

Supp LD = Vd * (Cprequired - Cpinitial)/S*F

Question 8

Clearance

Answer 8

Cl = SF(Dose/tau)/Cp

Question 9

Maintenance Dose

Answer 9

MD = ClCptau/S*F

Question 10

Elimination rate constant

Answer 10

Kel = Cl/Vd

Question 11

Half life

Answer 11

T1/2 = 0.693/Kel