Ch.2 Principles Of Drug Action

Question 1

What are the 3 phases of drug actions

Answer 1

1. Drug administration: drug is made available to body*
2. Pharmacokinetics: what body does to drug
   3.pharmacodynamics: what drug does to body

Question 2

What are the Routes of Administration (Drugs portal entry)

Answer 2

1. Enteral: absorption along GI (Tablet)
2. Parenteral: besides the intestine( IV)
3. Transdermal: to the skin (patch)
4. Inhalation: (Gas, aerosol)
5. Topical: to skin or mucous membrane ( lotion, ointment)

Question 3

What are some positive drug interactions

Answer 3

• Synergism
• Additivity
• Potentiation

Question 4

Synergism [ positive drug interaction]

Answer 4

Two drugs act on a target organ by different mechanisms

Question 5

Additivity [ positive drug interaction]

Answer 5

What two drugs act on the same receptors for maximal effect

Question 6

Potentiation [ Positive drug interaction]

Answer 6

Special case of synergism, one drug has no effect but can increase the activity of the other drug

Question 7

What are some drug responsiveness terms

Answer 7

-Idiosyncratic effect
- Hypersensitivity
- Tolerance
- Tachyphylaxis

Question 8

Idiosyncratic effect ( drug response)

Answer 8

Opposite of, or unusual, or an absence of effect

Question 9

Hypersensitivity ( drug response)

Answer 9

Allergic or immune mediated

Question 10

Tolerance (drug response)

Answer 10

Decreased intensity of response

Question 11

Tachyphylaxis (drug response)

Answer 11

Rapid decrease in response to a drug

Question 12

Potency vs. maximal effect

Answer 12

When a drug has a lower dosage but a high effect

Question 13

Therapeutic Index (TI)

Answer 13

Difference between minimal therapeutic and toxic concentration of a drug ( smaller the difference, greater the risk)

Question 14

Antagonist and agonist

Answer 14

Binds and initiate( agonist) or bind and cause no response (antagonist)

Question 15

Drug interactions

Answer 15

Chemical, functional or competitive antagonism

Question 16

What are the 4 factors increasing the L/T ratio

Answer 16

1. Efficiency
2. Inhaled drugs with high first-pass metabolism
3. Mouth washing, rinse and spit
4. Use of reservoir device

Question 17

What is L/T ratio and what’s the formula

Answer 17

Proportion of drug made available from the lung, out of the total systemic available drug. Higher the ratio, more aerosol delivered to drug
(Lung does)/(lung dose + GI dose)

Question 18

What is plasma half time (T 1/2)

Answer 18

A measure of how quickly a drug is eliminated from body

Question 19

What does kidneys do to drugs

Answer 19

Kidneys are the primary site of drug excretion

Question 20

What does liver does to a drug

Answer 20

Liver is primary site of drug metabolism