Unit 1 Key terms Flashcards
absorption
what happens to a drug from the time it enters the body until it enters the circulating fluid; intravenous administration causes the drug to directly enter the circulating blood, bypassing the many complications of absorption from other routes
active transport
the movement of substances across a cell membrane against the concentration gradient; 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 tissues; 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 that is biotransformed by a particular enzyme system in the liver causes increased activity of that enzyme system
excretion
removal of a drug from the body; primarily occurs in the kidneys, but can also occur through the skin, lungs, bile, or feces
first-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 circulation; oral drugs frequently are given in higher doses than drugs given by other routes because of this early breakdown
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 previously achieved
hepatic microsomal system
liver enzymes tightly packed together in the hepatic intracellular structure, responsible for the biotransformation of chemicals, including drugs
loading dose
use of a higher dose than what is usually used for treatment 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
