Questions and Answers
Updated 2026
PharmacokineticsBincludesB-BAnswerBabsorption,Bdistribution,Bmetabolism,Belimination
absorptionBofBdrugsBfactorsB-
BAnswerBPHBchanges,BgastricBemptying,BgastricBenzymes,BbileBacids,BGIBflora,BfoodBand
BnutrientBinteractions,BlipidBsolubility
WhereBisBcyp450BsystemBfoundB-BAnswerBendoplasmicBreticulumBofBhepatocytes
CYP3A4/5B-
BAnswerBmostBabundantBCYP450BisoformBwhichBmetabolizesBtheBmostBprescribed
"B"drugs.BEspeciallyBimportantBforBbioavailabilityBdueBtoBitsBabundanceBin
"B"cellsBliningBtheBGIBtract.BCanBbeBinducedBbyBaBwideBvarietyBofBdrugsB"
"andBisBpotentlyBinhibitedBbyBketoconazoleBandBerythromycin.
CYP2D6B-BAnswerBmetabolizesB25%BofBprescribedBdrugs
*3*4*5BmajorityBofBbadBmetabolizers
Antidepressants
Antipsychotics
Antiarrythmics
*carvedilol,B*metoprololB
*codeineB→Bmorphine
*tamoxifenBtoBactive
CYP2c8/9B-BAnswerBwarfarin
, CYP1A2B-BAnswerBAcetAminophen
CRAPBGPSBinducesBmyBrageB-BAnswerBcarbamazepine,Brifampin,
alcohol,Bphenytoin,Bgriseofulun,Bphenobarbitone,Bsulfonylureas
rectalBadminBhasBwhatBabsorptionB-BAnswerBvariableBandBerratic
steadyBstateB(SS)BisBusuallyBreachedBwithinBhowBmanyBhalf-livesBofBaBdrugB-
BAnswerB4-5
zero-order(nonlinear)BpharmacokineticsBmeansBaBdrugBisBmetabolizedB-
BAnswerBatBaBconstantBrateBperBunitBtime
Michaelis-mentenBpharmacokineticsB-
BAnswerBtheBrateBofBdrugBeliminationBisBdirectlyBproportionBtoBtheBconcentrationBofBfr
eeBdrugB(phenytoin)
theraputicBindexB-BAnswerBTD50B=BmedianBtoxicBdoseB
ED50B=BmedianBeffectiveBdose
windowB=BbetweenBthoseBdosesB
safeBdrugsBhaveBaBwiderBorBhighBwindow/index
AgonistB-
BAnswerBdrugsBthatBalterBtheBphysiologyBofBaBcellBbyBbindingBtoBplasmaBmembraneBor
BintracellularBreceptors
AntagonistsB(drugs)B-BAnswerBTheseBdrugsBblockBtheBactionsBcausedBbyBagonists