Chapter 2: Drugs and the Body Flashcards
(20 cards)
absorption
what happens to a drug from the time it enters the body until it enters the circulating fluid
active transport
the movement of substances across a cell membrane; this process requires the use of energy
chemotherapeutic agents
synthetic chemicals used to interfere with the functioning of foreign cell populations, causing cell death; this term is frequently used to refer to the drug therapy of neoplasms, but it also refers to drug therapy affecting any foreign cell
critical concentration
the concentration a drug must reach in the tissues that respond to the particular drug to cause the desired therapeutic effect
distribution
movement of a drug to body tissue; the places where a drug may be distributed depend on the drug’s solubility; perfusion of the area, cardiac output, and binding of the drug to plasma proteins
enzyme induction
process by which the presence of a chemical causes increased activity of an enzyme system
excretion
removal of a drug format he body; routes include the kidneys, skin, lungs, bile, and feces
fire-pass effect
a phenomenon in which drugs given orally are carried directly to the liver after absorption, where they may be largely inactivated by liver enzymes before they can enter the general circualtion
glomerular filtration
the passage of water and water-soluble components from the plasma into the renal tubule
half-life
the time it takes for the amount of drug in the body to decrease to one-half of the peak level it achieved
hepatic microsomal system
liver enzymes tightly packed together in the hepatic intracellular structure, responsible for the biotransformation of chemicals, including drugs
loading dose
a dose higher than what is usually used for treatment, administered to allow the drug to reach the critical concentration sooner
passive diffusion
movement of substances across a semipermeable membrane with the concentration gradient; this process does not require energy
pharmacodynamics
the study of the interactions between the chemical components of living systems and the foreign chemicals, including drugs, that enter living organisms; the way a drug affects a body
pharmacogenomics
the study of genetically determined variations in the response to drugs
pharmacokinetics
the way a medication travels through the body, including absorption, distribution, biotransformation, and excretion; how the body acts on the drug
placebo effect
documented effect of the mind on drug therapy; if a person perceives that a drug will be effective, the drug is much more likely to actually be effective
receptor sites
specific areas on cell membranes that react with certain chemicals to cause an effect within the cell
selective toxicity
property of a chemotherapeutic agent that affects only systems found in foreign cells without affecting healthy human cells (e.g., specific antibiotics can affect certain proteins or enzyme systems used by bacteria but not those used by human cells)
therapeutic index
a ratio comparing the blood concentration at which a drug becomes toxic with the concentration at which the drug is effective
