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15 terms

Pharmacodynamics

Intro
STUDY
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Pharmcodynamics
What the drug does to the body; involves the mechanism of action. Involves effect of drug concentration on body responses.
Interpatient Variability
Patients have widely different responses to drugs, which can be depicted on a frequency distribution curve.
Dose-response relationship
describes how the actions of a drug change with increasing dose. Drug dose correlates to degree of response. Three phases: 1. Lowest (administration) 2. Most desirable range 3. Plateau reached
Therapeutic Index
The ratio between the toxic and therapeutic concentrations of a drug. If the index is low, the difference between the therapeutic and toxic drug concentrations is small, and use of the drug is more hazardous.
Drug receptor interaction
-Binding of drug to receptor is usually reversible
-Turns receptor "on" or "off"
-Each receptor regulates a process and generates a response
-Strength of D-R complex is related to "affinity" = high affinity and the drug will have difficulty coming off the receptor
- Once occupied, reseptor triggers secondary messenger
Median Effective Dose
the dosage of a given drug at which 50% of clients experience a specific therapeutic effect. AKA Average dose or ED 50
Median lethal dose
(LD50)the dosage of a given drug at which 50% of clients experience a lethal effect
Channel Protein
A membrane protein that forms a channel or pore completely through the membrane and that is usually permeable to one or to a few water-soluble molecules, especially ions.
Secondary Messenger
method of cellular signaling whereby a hormone diffuses into a cell to activate proteins within the cell to cause a response
Phosphodation effect
type of cross membrane transport.
Passive diffusion
The movement of substances into or out of cells without the expenditure of energy or the involvement of transport proteins in the cell membrane. Also called simple diffusion.
Agonists
Mimic the action of endogenous substances (neurotransmitters); response may be greater than endogenous activity.
Endogenous
produced from within; due to internal causes
Antagonists
Prevents action of endogenous substance; may compete with agonist; useful in blocking excess endogenous activity
Partial Agonists
have only moderate intrinsic activity. Hence their maximal efficacy is lower than that of full agonists. • Partial agonists can act as agonists (if there is no full agonist present) and as antagonists (if a full agonist is present).