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43 terms

Principles of Drug Action and Drug Interactions

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Receptors
drugs form chemical bonds with specific sites, this bond forms only if the drug and its receptor have similar shape....lock and key idea...
Pharmacodynamics
The study of interactions between drugs and their receptors and the series of events that result in a pharmacologic response.
Agonists
drugs that interact with a receptor to stimulate a response
Antagonists
drugs that attach to a receptor but do not stimulate a response
Partial Agonists
drugs that interact w/ a receptor to stimulate a response BUT, inhibit other responses
ADME
Administered drugs that go through 4 stages: absorbtion, Distribution, Metabolism, Excretion
Pharmacokinetics
the study of the matematical relationships among how drugs are introduced into the body and then absorbed, distributed, metabolized, and excreted out of the body
Enteral
Given through the gastrointestinal system (G.I Tract) by oral, rectal, or nasogastric route include powder,pills tablets, liquids, and suppositories
Parental
fluids or medications are given by injection,(IV), intramuscular(IM), and subcutaneous (subcut)
Liberation
When a drug is released from its drug form and dissolved in body fluids before it can be absorbed.
Percutaneous
A method of drug administration that includes inhalation, sublingual (under the tongue), or topical (on the skin) administration.
Absorption
Process whereby a drug is transferred from its site of entry into the body to the circulating fluids of the body (i.e. blood and lymph) for distrubution around the body.
Distribution
Refers to the ways in which drugs are transported throughout the body by the circulating of body fluids to the sites of action (receptors), metabolism, and excretion
Drug Blood Level
An equilibrium is established between the respository site ( lipid tissue) and circulation so as it drops as a result of binding at the sites of physiologic activity, metabolism,or excretion, more drug is released from the lipid tissue
Metabolism (biotransformation)
The process in which the body inactivates drugs
Excretion
Elimination of med from the body through respiration, perspiration, urination, or defecation, elimination of the drug...2 primary routes...GI tract to the feces & thru the renal tubules into the Urine....other routes can be evaporation thru the skin, exhalation, secretion to saliva and breast milk
half-life
Defined as the amount of time required for 50% of the drug to be eliminated fr. the body
Pharmacodynamics
The study of interactions between drugs and their receptors and the series of events that result in a pharmacologic response.
Onset of Action
when the concentration of a drug at the site of action is sufficient enough to start a physiologic response
Peak Action
this is the time when the drug reaches its highest concentration at the receptor site, inc. the maximal pharmacologic response for the dose given
Duration of Action
the length of time a drug has a pharmacological effect.
Desired Action
The expected response that occurs when a drug enters a patient and is absorbed and distributed.
adverse effects/side effects
Unintended and usually undesired effects that may occur with the drug
Toxicity
harmful effects of a drug
Parameters
therapeutic actions to expect, side effects to expect , adverse effects to REPORT, & possible drug interactions
Idiosyncractic Reaction
Occurs when something unusual or abnormal happens when the drug is 1st administred
Allergic Reactions
a/k/a hypersensitivity reactions, occur in about 6% to 10% of patients taking medications which occurs in patients who have previously been exposed to a drug and have developed antibodies to it from their immune systems. On reexposure, the antibodies cause a reaction.
Urticaria
also hives; an acute allergic reaction in which round wheals (welts) develop on the skin, usually accompanied by intense itching
Carcinogenicity
is the ability of the drug to induce living cells to mutate & become cancerous
Placebo Effect
experimental results caused by expectations alone; any effect on behavior caused by the administration of an inert substance or condition, which is assumed to be an active agent
Nocebo Effect
Latin, "I will harm." The effect that occurs when the patient's negative expectations about therapy result in less than optimal outcomes.
Placebo
A physical or psychological treatment that contains no active ingredient but produces an effect because the person receiving it believes it will.
Tolerance
the diminishing effect with regular use of the same dose of a drug, requiring the user to take larger and larger doses before experiencing the drug's effect
Drug Dependence
characterized by habituation to, abuse of, and/or addiction to a chemical substance mostly due to psychological craving for the substance
Drug Accumulation
accumulation in the body may occur if the next dose is admin. before the previously admin. dose has been metabolized or excreted
Unbound Drug
portion of the drug that is pharmacologically active that provides a physiologic effect
Drug Interaction
is said to occur when the action of one drug is altered by the action of another drug. Are elicited in two ways 1. agents that when combined increase the actions of one or both drugs and 2. agents that when combined, decrease the effectiveness of one or both of the drugs. Usually affet the binding of a drug to an inactive site, such as circulating plasma albumin or muscle protein
Additive Effect
A drug interaction that occurs when two drugs with similar actions are taken, thus doubling the effect.
Synergistic Effect
when two drugs are administered together and interact in such a way that their combined effects are greater that the sum of the effects for each drug given alone
Antagonistic Effect
One drug interferes w the action of another
Displacement
The displacement of the first drug from protein-binding sites ( bound drugs are inactive) by a 2nd drug increases the activity of the 1st drug b/c more unbound drug is available.
Interference
The 1st drug inhibits the metabolism or excretion of the 2nd drug, causing increased activity of the 2nd drug.
Incompatibilty
The 1st drug is chemically incompatible with the 2nd drug, causing deterioration when both drugs are mixed in the same syringe or solution