Pharmacodynamics and Pharmacokinetics EC Flashcards Preview

Evan's Step 1 Prep Material > Pharmacodynamics and Pharmacokinetics EC > Flashcards

Flashcards in Pharmacodynamics and Pharmacokinetics EC Deck (15):
1

What is second order kinetics?

Rate independent of substrate concentration

2

What is first order kinetics?

Rate proportional to substrate concentration

3

Does a competitive inhibitor change Km or Vmax? How?

Competitive inhibitors increase Km but have no effect on Vmax.

Decrease potency

4

Does a noncompetitive (irreversible) inhibitor change Km or Vmax? How

Noncompetitive inhibitors decrease Vmax but have no effect on Km

Decrease efficacy

5

What is the formula for calculating volume of distrobution?

= drug in body/plasma drug concentration

6

What does a high/medium/low volume of distribution mean?

High=all tissues=small lipophilic
Medium=ECF=Small hydrophilic molecules
Low=Blood=Large/charged molecules

7

What is the equation for half life?

= (0.7 * Vd) / Clearance (CL)

8

What is the equation for loading dose?

= Css * Vd / (F)
(F=bioavailability, usually= 1 in questions)

9

What is the equation for maintenance dose?

= Css * CL / (F)

10

What is first order elimination?

Flow dependent elimination
PROPORTIONAL TO CONCENTRATION (ie set fraction)

11

What is zero order elimination?

Capacity dependent elimination
CONSTANT AMOUNT ELIMINATED

"PEA" - phenytoin, ethanol, aspirin

12

What is phase I metabolism?

Reduction, oxidation, or hydrolysis via CYP450

(geriatrics lose phase I first)

13

What is phase II metabolism?

Conjugation (glucouronidation, acetylation, sulfation).
Renally excreted

14

What is therapeutic index?

Lethal dose / Effective dose

Large TI means drug is safe

15

What are some examples of drugs with low therapeutic indexes?

Digoxin, Lithium, theophylline, & warfarin

Decks in Evan's Step 1 Prep Material Class (72):