Basic Pharmacology

Question 1

What is a drug?

Answer 1

Any substance that alters physiology of the body (not food or nutrient)
Definition must consider intention (vitamin C - not a drug but has drug-like properties)

Question 2

What is behavior?

Answer 2

Intake/processing information, integration of information, actions based on this processing, and many other things

Question 3

Illicit vs. licit drugs

Answer 3

Illicit = illegal
Licit = legal
Abuse can’t be determined by legality → recreational (pleasure) vs. instrumental (socially-approved goal)

Question 4

What is pharmacology?

Answer 4

Consists of two elements:
Pharmacodynamics - body’s biological response to drugs (what the drug does to the body)
Pharmacokinetics - movement of drugs throughout the body (what the body does to the drug)

Question 5

What are the different methods of naming drugs?

Answer 5

Chemical name (i.e. 7-chloro-1)
Generic (nonproprietary) name (i.e. Diazepam)
Trade (proprietary) name (i.e. valium)
Street name (i.e. downers, vitamin V)

Question 6

What units are dosages given in?

Answer 6

Milligrams (mg) - 1/1000 g
Keeps dosages constant in human adults, children, and other animals (less in humans than rodents)

Question 7

What is a dose response curve?

Answer 7

A graph of a drug’s potency and effectiveness that tests different doses of a drug (plotted on log scale)

Question 8

What is effectiveness?

Answer 8

Maximum effect at any dose
ED₅₀ - dosage effective in 50% of all cases

Question 9

What is potency?

Answer 9

Dose required for efficacy
Lower ED₅₀ = high potency
Higher ED₅₀ = low potency

Question 10

What is lethal dose?

Answer 10

The probability of adverse effects
LD₅₀ kills 50% of subjects

Question 11

What is the Therapeutic Index (TI)?

Answer 11

TI = LD₅₀/ED₅₀ (higher TI = safer drug)

Question 12

What is the Safety Index (margin of safety)?

Answer 12

More conservative version of TI
LD₁/ED₉₉ (lethal dose for 1%/effective dose for 99%)

Question 13

What are the different drug effects (2)?

Answer 13

Primary effects - the reason a drug is taken (i.e. Advil is taken for fever reduction)
Side effects - an effect that isn’t directly related to the reason for taking the drug (i.e. Advil is also an anti-inflammatory)

Question 14

What is Thalidomide and how does it demonstrate the different drug effects?

Answer 14

Thalidomide - mild sleeping pill
Marketed as “safe for pregnant women” → caused thousands of babies to be born with malformed limbs (drug tests don’t address all potential impacted populations)

Question 15

What is a ligand?

Answer 15

A chemical that binds with a particular molecule

Question 16

What is the difference between endogenous and exogenous?

Answer 16

Endogenous - from within the body
Exogenous - from outside the body

Question 17

What is the difference between an agonist and an antagonist?

Answer 17

Agonist - activates receptor
Antagonist - inactivates or blocks receptor
Some drugs are partial agonists or partial antagonists

Question 18

What are the different drug interactions (3)?

Answer 18

Antagonism - one drug diminishes the effectiveness of another drug
Additive effect - ED₅₀ decreases with drug A + drug B (compared to A alone)
Superadditive effect/potentiation - greater additive effect than what would be expected from adding A + B

Question 19

What are the different elements of pharmacokinetics (ADME)?

Answer 19

Absorption - how it gets in
Distribution - where it goes
Metabolism - what affects it/how it breaks down
Excretion - how it leaves

Question 20

What is a route of administration?

Answer 20

The way a drug gets into the body from the outside world; can use natural processes (ingestion, breathing) or artificial (injection)

Question 21

What is parenteral administration?

Answer 21

Injection through the skin into various parts of the body using a hollow needle and syringe and must be in a vehicle (liquid)

Question 22

What are the 4 common parenteral routes (in order of absorption)?

Answer 22

Intravenous (IV) or mainlining
Interperitoneal (IP) - into the cavity where the organs are
Intramuscular (IM)
Subcutaneous (SC or sub-q) - directly under skin layer

Question 23

Common routes of administration rated from highest to lowest peaks in blood levels:

Answer 23

Intravenous (IV)
Intramuscular (IM)
IM - oil
Subcutaneous (SC)
Oral/”per os” (PO)

Question 24

How do areas with more blood flow influence absorption?

Answer 24

Areas with more blood flow have faster absorption rates due to more capillaries (small vessels)

Question 25

How are drugs absorbed through inhalation?

Answer 25

Absorbed from the air into lungs → distributed throughout the body very quickly (rich in capillaries) Go directly to the brain without being processed in the liver

Question 26

How do gases and smoke move through the body?

Answer 26

Gas moves from high concentrations (inhaled in lungs) to low concentrations (blood in the lung capillaries) → rapid diffusion Blood concentration higher in the lungs than gas? → gas is exhaled

Question 27

How does intranasal administration work?

Answer 27

Some absorbed through lungs, most absorbed in mucous membrane of sinuses → efficient, fast delivery to nervous system

Question 28

What are the two potential routes of oral administration?

Answer 28

Swallow drug → digestive system Entry through buccal (mouth) membranes → avoids digestive system

Question 29

How does the digestive system absorb drugs?

Answer 29

Some is absorbed into the bloodstream in the stomach, most occurs in the intestines (food delays absorbtion) Walls of intestines are lined with capillaries behind membrane of intestinal wall (drug must be able to be dissolved in lipid bilayer of membrane for absorption to occur)

Question 30

How do you test the lipid solubility of drugs?

Answer 30

Equal parts water and oil → fixed amount of drug mixed in → drug levels measured in separated water and oil → very lipid soluble drugs are more concentrated in oil

Question 31

How does the degree of ionization (polarity) impact lipid solubility?

Answer 31

Lipid soluble = non-ionized molecules (NaCl) Hydrophilic = ionized molecules (Na⁺, Cl⁻) More lipid soluble drugs = more absorption More water soluble drugs = less absorption

Question 32

What is the lipid solubility of different organs in the digestive system?

Answer 32

Stomach = non-ionized, thus absorbed Blood = ionized, thus not absorbed back Intestine = ionized, thus not absorbed

Question 33

How does transdermal administration work?

Answer 33

Substances that are highly lipid soluble can be absorbed through the skin (slowest absorption method) Absorbed locally → transported into systemic circulation

Question 34

What is the difference in drug distribution based on lipid solubility?

Answer 34

Higher lipid solubility → concentrated in body fat outside the CNS (lower efficiency) Drugs must be lipid soluble to get past the blood-brain barrier Special transport systems allow non-lipid soluble drugs into blood

Question 35

How does the blood-brain barrier keep drugs out of the brain?

Answer 35

Tight junctions prevent large pores → very few things can pass through Fat-soluble molecules and molecules subject to active transport (i.e. glucose) can pass through

Question 36

How are most drugs excreted?

Answer 36

Most excreted through liver and kidneys, some is excreted in feces, sweat, and saliva

Question 37

What are the main functions of the kidneys?

Answer 37

Maintain salt-water balance (excrete excess water and unwanted substances in urine) Filter blood and reabsorb good stuff (non-lipid soluble/ionized substances are filtered out unless they use a special transport system)

Question 38

What does the liver do?

Answer 38

Molecules that enter are changed via enzymes (i.e. alcohol dehydrogenase changes alcohol into acetaldehyde)

Question 39

What is metabolism?

Answer 39

The process of restructuring molecules Produces metabolites (less active and less toxic than original state in most cases)

Question 40

What do enzymes do?

Answer 40

Combine chemical substances or break them apart using active sites (lock and key) → allow reactions to occur

Question 41

What are factors that alter drug metabolism?

Answer 41

Stimulation of enzyme system (one drug enters using one efficient enzyme system = fast metabolism) Depression of enzyme system (2 drugs enter competing for same enzymes = slow metabolism) Age (newborn and elderly = slowed drug metabolism)

Question 42

What is the therapeutic window?

Answer 42

Level of a drug in blood changes over time due to constant absorption, filtering, and excretion → plot absorption and excretion to determine when a drug is most effective