Fundamental Pharmacology Facts

Question 1

Drug

Answer 1

• A drug is a chemical substance used for:
  > Preventing, treating, or diagnosing disease
  > Preventing pregnancy
  > Recreational or other forms of abuse

Question 2

Pharmacology

Answer 2

• The study of drugs

- Divided into pharmacodynamics and pharmacokinetics

Question 3

Pharmacodynamics

Answer 3

• What drugs do to the body

…
- Receptor Agonism or Receptor Antagonism
…

Question 4

Pharmacokinetics

Answer 4

• What the body does to drugs and how fast it does it
• Administration
• Absorption
• Distribution
  …
• Redistribution
• Metabolism
• Excretion

Question 5

Pharmacotherapeutics

Answer 5

• Treatment of disease by drugs
• Most drugs are palliative
• Some drugs are curative

Question 6

Pharmacy

Answer 6

• Profession responsible for dispensing drugs

Question 7

Drugs that prevent

Answer 7

• Vaccines
• Anticoagulants
• Antiseptics

Question 8

Drugs that diagnose

Answer 8

• Radiographic contrast media (eg barium)

- Mydriatics for dilating pupils in ophthalmic exams

Question 9

Drugs that treat

Answer 9

Palliative

• Nasal decongestants
• Antihypertensives
• Anxiolytics
• Analgesics

Curative

• Antibiotics
• Antineoplastics

Question 10

Common drug characteristics

Answer 10

• Most drugs are organic compounds
• Most drugs originated from natural substances
• Most drugs have three names
  > Chemical name
  > Generic (official name)
  > Trade (proprietary name)
• All drugs have side effects

Question 11

Formulations

Answer 11

• Large variety
• Tablets
• Capsules
• Pills (antiquated!)
• Pearls
• Solutions
• Suspensions
• Ointments
• Tinctures
• Salves

Question 12

Routes of administration

Answer 12

- Enteral
     > Oral
     > Rectal
- Parenteral
     > Sublingual
     > Intramuscular
     > Intravenous
     > Subcutaneous
     > Intrathecal (injection straight into CSF)
     > Topical
     > Transdermal

Question 13

Factors that affect drug absorption and distribution

Answer 13

• Drug molecular size
• Drug solubility
• Conditions (blood flow; cell junctions; inflammation) at the sites of tissues to be penetrated by the drug

Question 14

Agonists

Answer 14

• Drugs that activate receptors

Question 15

Antagonists

Answer 15

• Drugs that block receptors

Question 16

Potency

Answer 16

• Dose required to produce minimum response

- “High potency” if it requires only a small amount to have an effect

Question 17

Efficacy

Answer 17

• Maximum magnitude of response

- “High efficacy” if it will produce a large effect

Question 18

Margin of safety

Answer 18

• Difference between toxic and effective dose
• “High margin of safety” if the amount of drug that’s required to produce a desirable effect is much lower than the amount required to produce a toxic effect
• Ideally want a high margin of safety

Question 19

Therapeutic index

Answer 19

• Ratio of toxic and effective dose

- Ideally want a high therapeutic index

Question 20

Duration of action

Answer 20

• Amount of time that the drug acts on the body

Question 21

Half-life

Answer 21

• Time required for 1/2 of the drug to be eliminated from the body

Question 22

Redistribution

Answer 22

• The drug is carried away from the site of action, usually by blood flow
• Lymph and other ECF can also redistribute it

Question 23

Metabolism

Answer 23

• The drug is modified to make it less active or more readily excreted
• Liver is the main organ of drug metabolism
• Also: lungs, GI tract, synapses, and blood stream
• Phase I and Phase II metabolism

Question 24

Excretion

Answer 24

• The drug (or its metabolite) is removed from the body
• Kidney is the main organ of drug excretion
• Also: lungs, liver, sweat, and saliva

Question 25

Phase I metabolism

Answer 25

- Occurs in lipophilic endoplasmic reticulum of liver and other cells - REDOX reactions to polarize drug molecules - Rate-limiting reactions require CYP450 enzyme - Some drugs induce CYP450 activity, and some inhibit it

Question 26

Phase II metabolism

Answer 26

- Couple drugs/metabolites with endogenous molecules - Catalyzed by transferase enzymes - Conjugating the drug makes it larger and more easily excretable

Question 27

Factors influencing duration of action and half-life

Answer 27

- Metabolism - Metabolic tolerance > Tolerance occurs when efficacy decreases > Either metabolic or cellular tolerance - Excretion - Body fat - Age

Question 28

Federal laws

Answer 28

- Food, Drug, and Cosmetic Act passed in 1938 > Defined drugs > Established FDA > Several amendments: creation of prescription drugs; standardized drug development process; distinguished between drugs and dietary supplments - Controlled Substances Act passed in 1970 > Created 5 schedules > Enforcement by DEA

Question 29

Drug development

Answer 29

- Monitored by FDA | - Very long and expensive process