Ch. 1 - Drug Action

Question 1

Drug

Answer 1

any chemical substance that affects living systems by changing their structure or function

Question 2

3 phases of drug action:

Answer 2

1. ) Pharmaceutic phase
2. ) Pharmacokinetic phase
3. ) Pharmacodynamic phase

Question 3

**Pharma(ceutic) phase****

Answer 3

(Dissolution)

• Solid form: needs to disintegrate
  * Tablet > disintegration > dissolution
• Liquid form

Question 4

Pharma(ceutic) phase: Enteric Coated

Answer 4

RESIST disintegration in STOMACH
-------------------------------------------------------------
DISINTEGRATES in the SMALL INTESTINE 
\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_
should NOT be crushed

Question 5

Pharma(ceutic) phase cont…

Answer 5

Food in GI tract:

 * may interfere 
 * may enhance

Question 6

**Pharmaco(kinetic )Phase*****

Answer 6

• kinetic* = means ‘movement’
• process of drug movement to achieve drug action
  
  1. ) Absorption
  2. ) Distribution
  3. ) Metabolism (biotransformation)
  4. ) Excretion (elimination)

Question 7

Pharmaco(kinetic )Phase: Absorption

Answer 7

Gastric absorption influnced by:
*food, gastric pH

Question 8

Absorption cont.

Answer 8

bioavailability (subcategory)

  * % of drug dose that reaches the system       circulation 
  * Ex: taking it orally compared to intravenously

Question 9

Pharmaco(kinetic )Phase: (1) Distribution

Answer 9

drug becomes available to body fluids and body tissues

Question 10

Distribution (2)

Answer 10

Drug enters bloodstream –> rapidly carried to organs with blood supply

Question 11

Distribution (3)

Answer 11

Influenced by:

- blood flow
- drug's affinity to the tissue
- protein-binding effect

Question 12

Pharmaco(kinetic )Phase: Protein-binding Effect

Answer 12

• portion of the drug that is bound (to protein):
  * inactive (not available to receptors)
• Unbound portion:
  * free (active) = pharmacologic effect

Question 13

3.) Metabolism (biotransformation):

Answer 13

IF NOT water soluble = biotransformation occurs to convert to a more water soluble form

Question 14

Metabolism (biotransformation): cont..

Answer 14

Age, hepatic disease = slow down ability
———————————————————-
Liver = primary source of metabolism

Question 15

Half-Life:

Answer 15

-time it takes for 1/2 of drug to be eliminated from body
(Ex:)
Half-life: 4 hrs
{Every 4 hr interval drug conc. decreases 50%}
*Initial (8am) = 100% (500mg)
*After 4 hrs = 50% (250mg)
*After 8 hrs = 25% (125mg)
*After 12 hrs = 12.5% (62.5mg)
*After 16hrs = 6.25% (31.25mg)

Question 16

4.) Excretion (Elimination):

Answer 16

Kidney function affected by:
*age, kidney disease

Question 17

Pharmacodynamic phase**

Answer 17

drug concentration & its effects on the body

*Mechanism of action

Question 18

Drug Response: Primary or Secondary

Answer 18

diphenhydramine (Benadryl)

• Primary effect:
  - treat symptoms of allergy
• Secondary effect:
  - CNS depression –> drowsiness

Question 19

Onset:

Answer 19

time it takes to reach minimum effective concentration (occur)

Question 20

Peak:

Answer 20

drug reaches its highest blood concentration (level)

Question 21

Duration:

Answer 21

length of time drug has a pharmacologic effect

Question 22

Receptor Theory:

Answer 22

• drugs most commonly form a chemical bond with specific receptors in the body
  * lock & key relationship

Question 23

Agonist:

Answer 23

interacts with receptor to produce a response

Question 24

Antagonist:

Answer 24

inhibits or prevents action of an agonist or blocks a response

Question 25

Therapeutic Range (Window):

Answer 25

Low Therapeutic Index (TI) = narrow margin of safety
———————————————————
High TI = wide margin of safety

Question 26

Peak level:

Answer 26

highest plasma concentration at a specific time —-(measures rate of absorption)

Question 27

Trough level:

Answer 27

lowest plasma concentration (measures rate of excretion)

Question 28

Loading Dose:

Answer 28

Large initial first dose when an immediate drug response is desired
**Ex: Z-pack = take 2 doses first day, then 1 dose after that

Question 29

Side effects:

Answer 29

acts on other tissues besides specific intended issue

Question 30

Adverse effects:

Answer 30

unpredictable (idiosyncratic) adverse effects
-allergic hypersensitivity d/t individuals immune system
————————————————————–
Severe allergic reaction > anaphylaxis > resp./circ. collapse > death

Question 31

Toxicity

Answer 31

• ALL drugs are able to be toxic if dosage is high enough*

- related to dosage

Question 32

Teratogenic Effect:

Answer 32

congenital defect in fetus whose mom took drug during pregnancy

Question 33

Drug Tolerance:

Answer 33

resistance to effect of drug

-need higher dosage/frequency to produce desired effect

Question 34

Placebo Effect:

Answer 34

Psychological benefit from taking a chemical compound

- Persons feels that the pill will make them feel better