435-bioavailability 3

F=

Qh / [Qh + fu + CLint]

low Eh drugs

drugs are NOT subject to first pass

F is close to 1

no affected by changes in CLint, fu, Qh

high Eh drugs

significant first pass

F is small

yes affected by changes in CLint, fu, Qh

low Eh drugs + inducer

a lot more drug is extracted [inc Qh + CLint] ; greater F?

high Eh drugs + inducer

not much of a diff bc it’s already metabolized a lot so F doesn’t get affected much

low Eh drugs + inhibitor

not much change bc it’s already a poor substrate for hepatic metabolism

high Eh drugs + inhibitor

major change bc less of drug is extracted = less F

larger AUC

greater drug exposure

smaller AUC

smaller drug exposure

low Eh drugs AUC iv

affected by fu and CLint (protein binding)

high Eh drugs AUC iv

affected by Qh only

AUC oral = CL / F

changes in CL and F affect AUC oral

CL/F =

Dose oral / AUC oral

low Eh drugs A>B

Qh> fu x CLint

high Eh drugs B>A

Qh<fu x CLint

low Eh drugs bioA

F=1

high Eh drugs  bioA

F= Qh / fu x CLint

low Eh drugs F

F is NOT affected by changes in fu, CLint, Qh

low Eh drugs CLh

CLh is affected by changes in fu, CLint

high Eh drugs F

F is affected by changes in fu, CLint, Qh

high Eh drugs CLh

CLh is proportional to Qh

inc CLint

inc CLh

AUC and CL inversely related

AUC = dose/CL

low and high Eh drugs have same factors affected AUC oral

fu + CLint

bc the equation is the same: CLoral = fu x CLint

AUC iv

goverened by CL so anything that affects that affects AUC iv

AUC oral

govererned by CL oral [CL and F]