Pharmacodynamics

Question 1

Definition of Pharmacodynamics

Answer 1

• Actions of drug on the body (where does it bind, duration of action)
• Agonists
• Antagonists
• Partial agonists

Question 2

Ligand

Answer 2

Think of that as a drug or something natural like serotonin

Question 3

Receptors

Answer 3

• Determine the efficacy of a drug (# of receptors, affinity of receptors)
• Determine selectivity of a drugs action (molecular size, shape, electrical charge of a drug. At the site of action)
• Mediate actions (Agonists, antagonists)

Question 4

Affinity of receptors

Answer 4

Ability of drug to bind to that receptor

Question 5

Antagonists

Answer 5

A drug will bind and stop another action from happening

Question 6

Competitive antagonists

Answer 6

Reversible, increasing concentrations (larger doses, more frequent dosing) the stable agonists (whether natural or drug) will progressively be inhibited
–High concentrations of antagonists may be very effective
–High concentrations of agonists may not be offset by antagonists
Example: naloxone-the more naloxone you give to a stable opioid will overcome that opioid the more you give

Question 7

Irreversible Antagonists

Answer 7

Forms of covalent bonds or binds tightly and cannot be displaced
–ability for agonists to work may depend on how many receptors are occupied
–Duration of action often depends on rate of turnover of receptor molecule
Example: aspirin of omeprazole-they form a bond that cannot be broken

Question 8

Agonist

Answer 8

Will produce the same affect that the natural body ligand would-this would be like giving norepinephrine or epinephrine

Question 9

Partial and Full agonists

Answer 9

• Partial-produce lower response that full
• Concentration effect-curve may look more like a full agonist with a irreversible antagonist blocking some of the receptor sites
• -Partial: competitively inhibit responses produced by full agonists

Question 10

Types of receptors

Answer 10

• Regulatory proteins
• Enzymes
• Transport Proteins
• Structural proteins

Question 11

Dose Response

Answer 11

• EC50-the concentration of drug that produces 50% of the maximal response
• Emax: the maximal responses that can be produced by the drug
• Potency EC50-depends on the affinity of the receptor

Question 12

Efficacy

Answer 12

Dose not rely on potency; this is the drug’s maximal effect (BP, increased contractility, diuresis)

Question 13

Drug response: Idiosyncratic

Answer 13

Infrequently observed response

Question 14

Drug response: Hyporeactive

Answer 14

Lower response than generally observed

Question 15

Drug response: Hyperreactive

Answer 15

more robust response than generally observed

Question 16

Drug response: Tolerance

Answer 16

Responsiveness to a drug diminishes over time

Question 17

Drug response: Tachyphylaxis

Answer 17

Responsiveness to a drug diminishes rapidly after administration

Question 18

Beneficial vs. Toxic effects

Answer 18

• Receptors all over the body in different cells, tissues

- Many drugs bind to multiple receptors, though some greater than others