Ch. 5: Pharmacodynamics

Question 1

Dose-Response Relationships

Answer 1

• between size of an administered dose and intensity of response produced
• determines: min. amount of drug to be used, max. response a drug can elict, how much to increase dosage to produce desired increase in response
• as dosage increases, response becomes progressively largers
• treatment is tailored by increasing or decreasing dosage until desire intensitity
• 3 phases

Question 2

Max Efficacy and Relative Potency

Answer 2

max efficacy: largest effect drug can produce (height of curve), match intensity of responses with patient’s need, very high max is not always most desirable
relative potency: amount that must be given to elict response, rarely an important characterisitic of drug, can be important if a lack of potency forces inconveniently large doses, refers to dosage needed to produce effects

Question 3

Drug-Receptor Interactions

Answer 3

• receptor refers to body’s own receptors for hormones, neurotransmitters, and other regulatory molecules
• usually reversible
• regulated by endogenous compounds
• it will mimic or block action of endogenous regulatory molecules and increase/decrease rate normally controlled by that receptor

Question 4

4 Primary Receptor Families

Answer 4

• cell membrane-embedded enzymes
• ligand-gated ion channels
• G protein ion channels
• transcription factors

Question 5

Selectivity of Drug Action

Answer 5

• more selective= fewer side effects

Question 6

Affinity and Intrinsic Activity

Answer 6

• strength of the attraction

- ability of drug to activate a receptor upon binding

Question 7

Agonist, Antagonist, and Partial Antagonist

Answer 7

• activate receptors, endogenous regulators, have affinity and high intrinsic activity, make process go faster or slower
• preventing receptor activation by endogenous regulatory molecules and drugs, affinty but no intrinsic activity, no effects, if no agonist present an antagonist will have no observable effect
• can do both actions, moderate intrinsic activity

Question 8

Noncompetive vs. Competitive Antagonist

Answer 8

• bind irreversibly t receptors, reduce max. response that an agonist can elicit (fewer receptors), impact not permanent (breaking down old receptors and making new ones)
• compete with agonists for receptors, bind reversibly to receptors, equal affinity= receptor occupied by whichever agent is present in the highest concentration

Question 9

Regulation of Receptor Sensitivity

Answer 9

• continuous exposure to agonist= desensitized or refractory

- continuous exposure to antagonist= hypersensitive