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Flashcards in PharmacoKinetics Deck (55)
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1

Therapeutic Index :

Formula

LD50/ED50
Bad/Good

2

Smaller therapeutic index =

More LETHAL

3

MORE efficacy -- curve goes

Up

4

MORE potency - curve goes

Left
EC50 less

5

QD
Quaque die

1 per day

6

BID
Bis in die

2 per day

7

TID
Ter in die

3x per day

8

QID
Quater in die

4x day

9

Q#h

Every # hours

10

P.r

Rectal

11

I.d.

Intradermal

12

P.o.
Per os

Oral

13

Infusion (continous) for Rx with

Short half life

14

Intermittent infusion (short durations at intervals) for Rx w/

Long half life
irritate veins

15

Pharmacokinetics

How Rx's PLASMA CONCENTRATION changes over TIME

16

Drug IN

Concepts:

*Bioavailability (F)
*Starting concentration (C0), Dose (D)
*Apparent volume of d (Vd)

17

DRUG OUT

Concepts

Vd
1 compartment:
0-order kinetics
1-order kinetics
T1/2, Kel (elimination), Cl (clear)
Css (steady state), MD/D*
2 compartment

18

Steady state needs

Fixed dose at fixed interval

19

Affect Co (starting conc)
(Drug in)

Absorption
Distribution

20

Affect t1/2
(Drug out)

Distribution
Metabolism - ELIMINATE
Excretion - ELIMINATE

21

Bioavailability (F) =

F = AUC oral/AUC iv
0 = F = 1

Fraction absorbed into plasma

22

Dose conversion (oral - iv)

(Mg, mg/kg)

Di.v. = F x Doral

23

Vd =

(L\kg)

Vd = Di.v./Co

FROM Co = Di.v. / Vd
Conc=Mass/vol

24

Elimination constant (Kel) =

(1/hr)

Kel = .7 / t1/2

25

Clearance (Clp) =

(L/hr/kg)

Clp = Kel x Vd

26

Half life (t1/2) =

(Hr , min)

T1/2 = 0.7 x Vd / Clp

27

Maintanence Dose (MDi.v.) =

mg/hr/kg

MDi.v. = Css x Clp

28

Interval Dose (Di i.v.) =

(Mg/kg)

Di i.v. = MDi.v. X interval duration

29

Loading dose (D*i.v.) =

(Mg/kg)

D* i.v. = Css x Vd

30

Zero order =

Single compartment
Fixed rate
NOT concentration-dependent