Pharm p. 242-244 Flashcards Preview

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Flashcards in Pharm p. 242-244 Deck (42)
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1

What variable represents Michaelis-Menten constant?

Km

2

enzymatic reactions that exhibit a sigmoid curve usually ----- kinetics.

indicate cooperative

3

Km is ---- related to the affinity of the enzyme for its substrate.

inversely

4

Most enzymatic reactions follow hyperbolic
curves like:

Michaelis-Menten kinetics

5

Vmax is directly proportional to the enzyme ----.
.

concentration

6

Formula for Km? Km =

Km = [S] at 1/2 Vmax

7

According to Michaelis-Menten kinetics, Vmax is the point at which the enzymes are ----.

saturated

8

In Lineweaver-Burk plot, the higher the y-intercept, the ---  Vmax.

lower

9

In Lineweaver-Burk plot, on the x-axis, the closer to zero, the ---- the Km and the ---- the affinity.

greater
lower

10

How can one distinguish btw reversible and non-reversible inhibitors on the Lineweaver-Burk plot?

Reversible competitive inhibitors cross each
other competitively, whereas noncompetitive
inhibitors do not.

11

Do irreversible Competitive inhibitors bind to the active site?

Yes, only Non-comp. don't.

12

T or F? Irreversible Competitive inhibitors incr Vmax.

F. decr

13

T or F? reversible Competitive inhibitors dcr Km.

F. incr

14

T or F? Irreversible Competitive inhibitors incr efficacy.

F. decr

15

T or F? reversible Competitive inhibitors decr efficacy.

F. Unchanged

16

Which kind of inhibitors can be overcome by incr [S]?

reversible Competitive inhibitors

17

Formula for Vd?

Vd = (amount of drug in the body) /
(plasma drug concentration)

18

Liver and kidney disease decr protein binding to drugs causing --- Vd.

incr

19

Drugs that are large/charged molecules and plasma protein bound have a ---- Vd.

Low

20

Drugs that are small lipophilic molecules and bound
to tissue protein are found in which tissues?

All tissues, specially fat tissue

21

Formula for Cl?

CL= (rate of elimination of drug) /
(plasma drug concentration)

22

Formula for Cl in terms of Vd?

Cl = Vd × Ke (elimination constant)

23

If a drug is mostly found in the blood, what is its Vd?

low

24

Time to steady state depends primarily on --- and is independent of ---- ----.

t1/2
dose and dosing frequency

25

Loading dose =

Loading dose = (Cp × Vd) / F

26

A drug infused at a constant rate takes --- half-lives
to reach steady state.

4–5

27

Maintenance dose =

MD = (Cp × CL × τ) / F

28

t1/2 =

t1/2 = (0.693 × Vd) / CL

29

It takes --- half-lives to reach 90% of the steady-state level.

3.3

30

In renal or liver disease, maintenance dose ---  and
loading dose is usually -----.

decr
unchanged