Chapter 2 Drug Action and Handling Flashcards
(21 cards)
A function of the amount of drug required to produce an effect
Potency
The maximum intensity of effect or response that can be produced by a drug, increasing the drug after this point will not change potency but increase risk for an adverse reaction.
Efficacy
A ratio of median lethal dose (LD50) to the median effective dose (ED50)
TI = LD50/ED50
Therapeutic index
Desired effects on target tissues by a drug
Therapeutic effect
A drug that has an affinity for a receptor, combines with the receptor, and produces an effect, includes naturally occurring neurotransmitters
Agonist
Contracts the action of an agonist
Antagonist
Has an affinity for the receptor, combines with the receptor, produces no effect, causes a shift right in the dose-response curve
Competitive antagonist
Bind to a receptor site that is different from the binding site for the agonist. Its presence reduces the maximum response of the agonist
Noncompetitive antagonist
For a drug to exert its effects it must do what?
Bind with the receptor site on a cell membrane (lock-and-key action — specific drug binds with specific receptor)
Has affinity for different receptor site than the agonist, its presence decreases the maximal response of the agonist by producing an opposite effect via different receptors
Physiologic antagonist
Factors that influence the movement of drugs in the body are?
ADME (absorption, distribution, metabolism, excretion)
Lipid-soluble substances move across the lipoprotein membrane by a passive transfer process called?
Simple diffusion
Difference in concentration
Concentration gradient
A process by which a substance is transported against a concentration gradient or electrochemical gradient. This action is blocked by metabolic inhibitors.
Active transport
Doesn’t move against the concentration gradient. Involves the transport of some substances into cells, like glucose.
Facilitated diffusion
The process by which drug molecules are transferred from the site of administration to the circulating blood. This process requires the drug to pass through biologic membranes.
Absorption
Oral absorption of a drug requires what steps?
- Disruption
- Disintegration
- Dispersion
- Dissolution
Drugs that are least soluble will have the longest what?
Duration of action
The passage of drugs into various bodily fluid compartments like plasma, interstitial fluids, and intracellular fluids.
Distribution
Lipid-soluble drugs penetrate what membrane most easily?
The placenta
