Pharmacology, Pharmacokinetics Flashcards Preview

PSY1201 > Pharmacology, Pharmacokinetics > Flashcards

Flashcards in Pharmacology, Pharmacokinetics Deck (37):
1

Dose

Amount of drug given
Usually expressed in mg/kg
Measure of efficacy
See the minimally effective dose
Important in drug safety

2

Dosage

Administration of drug per unit of time

3

Pharmacodynamics

The action of drugs and their mechanism of action

4

Affinity

Ability to bind to the receptor

5

Efficacy

Degree of biological activity

6

Agonist

Ligand that binds to receptor to elicit a response

7

Indirect Agonist

Molecule that does not bind directly to a receptor but increases the amount of exogenous ligand

8

Partial Agonist

Agonist that has an intermediate activity at the receptor

9

Antagonist-

Molecule that binds to receptor but has no intrinsic activity

10

Inverse Agonist

Agonist that binds to the receptor but has the opposite effect

11

Mixed agonist/antagonist

Acts as an agonist that blocks the effect of another agonist

12

Potency

Amount of drug required to produce a specific effect of given intensity as compared to a standard reference
Considers both affinity and efficacy

13

4 Principles of Pharmacokinetics

Absorption- Get drug into blood stream
Distribution- Get drug to target organ
Metabolism- Usually inactivates the drug, sometimes makes it more active
Excretion- Removes drug from Body

14

Time Effect Curves

Provides documentation of how much drug enters the body per unit time
Profile- Gradual increase in levels until peak concentration and then a decrease over time
Many variable control this time profile

15

Duration of Action

The amount of time spent in the therapeutic range

16

Routes of Administration

Oral- easy but slow
Inhalation- Fastest
Injection
Topically- Slow and erratic
Buccal- gums and cheeks
Rectal- Generally Slow

17

Determinants of Dissolution

Dissolution Rates
Gastric Emptying Rate
Intestinal Motility
Drug Interactions in Gut Lumen
Passage Through Gut Wall

18

Dissolution Rates

Physiochemical properties
Crystal size and form
Special Formulation- sustained release

19

Gastric Emptying Rate

Stability of drug at acid pH
Solution or solid
Presence of other food items: food, antacids, other drugs, disease of stomach

20

Intestinal Motility

Dissolution of slowly soluble drugs
Chemical degradation or metabolism by microflora that live in the GI system

21

Drug Interactions in Gut Lumen

Complexation
Adsorption
Food interactions

22

Passage Through the Gut wall

-physiochemical characteristics of drug
Metabolism by enzymes in the intestinal endothelium

23

Drug -Phillic

Lipophilic- Pass easily through gut wall, more easily absorbed
Hydrophillic- Easily dissolved in blood but harder to pass through gut wall

24

Sustained Release Formulation

Drug levels more stable over time, fewer side effects, better medication compliance
Most offer once a day dosing, but some injections offer once a month

25

Blood Level Monitoring

Gold Standard for detecting drugs and whether they are biologically active
5-10 ml sample is collected for analysis

26

Blood Brain Barrier

Keeps large molecules out of the blood
Composed of specialized cells that alter the function of the capillaries
Block the junction between capillaries and cover the area with a glial sheath

27

Metabolism

Process of breaking down a drug or food so it can be utilizes/eliminated
Generally, lipid soluble chemicals are broken down into water soluble chemicals

28

Biotransformation

Preparation for elimination

29

First Pass Effect

Extent to which the liver removes drug from blood as it is passing through the portal vein before entering systemic circulation

30

Metabolism

Enzymes in the liver regulate metabolism
High amount of interindividual variation
Cytochrome P450 type is major enzyme
Small molecules --> kidney --> urine
Large molecule --> intestine --> feces

31

Cytochrome P450

Enzyme located in hepatocytes
Diverse gene that metabolizes wide range of drugs and food

32

Elimination

Primary Route through feces/urine
- Also through saliva, tears, breath and sweat

33

Urine Screen Drug Test

Principal way to measure if someone has taken drugs
Low cost and relatively sensitive
- See active drugs or metabolites
- Gives no indication to amount or when taken

34

Faking a Urine Screen

- Used at many work locations
Several products, including artificial urine and dispensing devices to help fake

35

Non-Urine Drug Tests

Hair- 1 week to 3 mos
Oral- 1-2 days
Urine 3-5 days
Blood minutes to days

36

Hair Drug Test

- Minute amounts of drug get trapped in hair cortex
- Tracks drug use over months
Simple and non-invasive
Results stand up in court
CON
Expensive
Some tests can take 5 days
Only a dozen drug classes can be used

37

Placebo Response

Inert substance
response can be measured
Works best on symptoms and signs that oscillate throughout the illness
- More related with an expectancy or desire for the drug to work
-Placebo manipulations reduce neuronal activity in regions that are sensitive to pain
- Reductions in activity associates with perceived reduction in pain