Practice 4th Edition By Michael P. Adams; Carol Quam
Urban
Pharmacodynamics - ANSWER:The study of how drugs change the drug action and
the relationship between drug concentration and responses in the body.
Frequency distribution curve - ANSWER:A graphic representation of the number of
patients responding to a drug at different doses.
Median effective dose - ANSWER:The dose in the middle of the frequency
distribution.
The dose required to produce a specific therapeutic response in 50% of the patients.
ED50
Average or standard dose for a drug
Median Lethal Dose - ANSWER:LD50
Dose of a drug that will kill 50% of animals drug is tested on.
Therapeutic Index - ANSWER:Ratio of median lethal Dose (LD50)/median effective
dose (ED50)
What is the therapeutic index used for? - ANSWER:To examine the safety margin of a
particular drug
What does the nurse know about the numerical value of the therapeutic index as
related to the safety of the drug? - ANSWER:Drugs with a low TI should be
administered at the lowest dose initially and increase with careful monitoring.
Assess hepatic and renal function before starting therapy
Median Toxicity Dose - ANSWER:The dose that will produce a toxic effect in 50% of
patients.
Margin of Safety - ANSWER:Amount of drug that is lethal to 1% of animals (LD1) /
amount of drug that is therapeutic in 99% of animals (ED99).
What does the nurse know about the MOS? - ANSWER:The higher the MOS, the
safer the medicine.
Dose Response Relationship - ANSWER:Compares the drug dose administered to the
patient versus the intensity or degree of response obtained.
Describe the 3 phases of the dose response relationship - ANSWER:Phase 1: Occurs
at the lowest dose
, Phase 2: Amt of drug= amount of response
Phase 3: Plateau--no increase in therapeutic result if drug is increased
What is the nursing implication for increasing the dose of a drug in phase 3? -
ANSWER:Could produce toxicity.
Potency - ANSWER:Amount of drug needed to produce a specified effect.
Efficacy - ANSWER:The maximum response that can be produced from a particular
drug.
Name the two ways to compare drugs within therapeutic and pharmacologic
classes? - ANSWER:Potency and Efficacy
Which is more important from a pharmacy perspective? - ANSWER:Efficacy
What does the nurse need to remember about adverse effects and higher doses? -
ANSWER:Adverse effects increase with higher doses only when comparing doses of
the same drug.
Receptor - ANSWER:A cellular molecule to which a medication binds to produce its
effects.
Proteins bound to plasma membranes
Intracellular molecules (DNA)
Enzymes in the cytoplasm
Intrinsic activity - ANSWER:Drugs that have the ability to bind to a receptor and
produce a strong action have this characteristic.
High intrinsic activity and high efficacy are related.
Receptor theory - ANSWER:Predicts that the response of the drug is proportional to
the concentration of the receptors that are occupied by the drug.
Examples of agents that bind intracellular components - ANSWER:Steroid hormones
Vitamins
Agonist - ANSWER:A drug that activates a receptor and produces the same response
as the endogenous substance.
Results in a maximum response
Antagonist - ANSWER:A drug that occupies a receptor and prevents the endogenous
chemical from binding to produce an action.
Results in little or no response
When are antagonists used as medications? - ANSWER:When the body is producing
too much of a response from an endogenous chemical or from a drug overdose.