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Pharmacology Ch 2
Basic Principles of Drug Action and Drug Interactions
Term | Definition |
---|---|
Receptor | Chemical bonds formed with specific sites |
Pharmacodynamics | The study of the interaction between drugs and their receptors 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 Agonist | Drugs that interact with a receptor to stimulate a response but inhibit other responses |
Enteral | Drug is administered directly into the gastrointestinal tract by the oral, rectal, or nasogastric route |
Parenteral | Drugs bypass the GI tract with the use of subcutaneous, intramuscular, or intravenous injection |
Percutaneous | Drugs being absorbed through the skin and mucous membranes. Inhalation, sublingual (under the tongue), and topical (on the skin) administration. |
Pharmacokinetics | The study of the mathematics relationships among the ADME features of individual medicines over time |
Absorption | The 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 distribution around the body. |
Distribution | The ways in which drugs are transported throughout the body by the circulating body fluids to the sites of action or to the receptors that the drug effects. |
Drug blood level | An assay to determine the amount of drug present in a blood sample |
Metabolism | The process whereby the body inactivates drugs |
Excretion | The elimination of drug metabolites and, in some cases, of the drug itself from the body |
Two primary routes of excretion | Through the GI tract into feces and through renal tubules into urine |
Other routes of excretion | Evaporation through the skin, exhalation through the lungs and secretion through saliva or breast milk |
Half -Life | The amount of time required for 50% of the drug to be eliminated by the body |
Onset of Action | When the concentration of a drug at the site of action is sufficient to start a physiologic (pharmacologic) response |
Peak Action | The time at which the drug reaches the highest concentration on the target receptor sites, thereby inducing the maximal pharmacologic response for the given dose |
Duration of Action | How long the drug has pharmacologic effect |
What happens if a drug does not reach the minimum effective concentration? | There will be no pharmacological effect |
What happens when the peak level exceeds the toxicity threshold? | Toxic effects will result |
The drug concentration is targeted to be in the? | Therapeutic range, between the minimum effective response and the toxic response. |
Desired Action | The expected response |
Side Effects | The potential to affect more than one body system simultaneously |
Adverse Effects | The undesirable responses produced by a drug (other than the intended effect) when it affects more than one body system |
Toxicity | A severe adverse effect |
Idiosyncratic reaction | When something unusual or abnormal happens when a drug is firs administered |
Allergic Reactions | Hypersensitive reactions of patients who are taking medications |
Drug Interactions | Said to occur when the action of one drug is altered by the action of another drug. Combined they increase or decrease the effectiveness of one or both drugs |
Unbound Drug | A drug that is able to diffuse, interact with receptors, and produce physiologic effects |
Additive Effect | Two drugs with similar actions are taken together for an increased effect |
Synergistic Effect | The combined effect of two drugs is greater than the sum of the effect of each drug given together |
Antagonistic Effect | One drug interferes with action of the another |
Displacement | The displacement of the first drug from protein-binding sites by a second drug increases activity of the first drug because more unbound drug is available |
Interference | The first drug inhibits the metabolism or excretion of the second drug, thereby causing increased activity of the second drug |
Incompatibility | The first drug is chemically incompatible with the second drug, thereby causing deterioration when the drugs are mixed in the same syringe or solution or are administered together at the same site. |