lecture 17

Question 1

identify the portions of a concentration vs time curve that are associated with onset, duration, and intensity of pharmacologic effect

Answer 1

onset: the time it takes from administration to the first intercept of MEC, how long it takes for the drug to act

duration: the time from the first intercept of MEC to the second intercept of MEC, how long the drug effect lasts

intensity: peak of the curve, peak effectiveness of the drug

Question 2

provided a route of administration, identify barriers that may reduce the amount of drug that reaches the site of action

Answer 2

a reduction in the extent of absorption will impact the intensity (if you get less drug, it will cause less effect) and duration (if intensity is reduced, curve is shifted down shortening the duration)

a reduction in the speed of entry into the systemic circulation will impact onset-

Question 3

define disposition, pharmacokinetics, and pharmacodynamics

Answer 3

disposition: the fate of a drug after it has entered the systemic circulation

pharmacokinetics: the study of the absorption, distribution, and elimination of xenobiotics

pharmacodynamics: the study of the molecular, biochemical, and physiological effects of xenobiotics and their mechanisms of actions:

Question 4

identify what percent of drugs currently fail in clinical trials due to problems with ADME

Answer 4

only 12-16% of drugs make it to the clinical trial stage

Question 5

identify the primary routes of administration

Answer 5

ingestion (oral)
inhalation (nasal or inhalers)
dermal (patches)
parenteral (injections)

Question 6

describe the four potential consequences of drug metabolism (biotransformation) as it relates to pharmacologic activity

Answer 6

absorption: barriers to absorption can reduce the speed and/or extent by which the drug enters the systemic circulation

distribution: differences in distribution can cause differences in side effects

metabolism: active drug to inactive metabolite, active drug to active metabolite, inactive drug to active metabolite (prodrugs), active drug to reactive metabolite

excretion: renal and biliary are the major routes of excretion. other routes include pulmonary (breathalyzers), salivary, and mammary. differences of excretion may impact drug choice because of renal failure, etc.