CH.2 Pharmacokinetics and factors of individual variation Flashcards
Bioavailability
Percentage of the drug dosage that is absorbed
Drug absorption
Entrance of a drug into the bloodstream from its initial site of administration
Drug addiction
Condition of drug abuse and dependence that is characterized by compulsive drug behavior
Drug dependence
Condition of reliance on the use of a particular drug, characterized as physical and or psychological dependence
Drug Distribution
Passage of a drug from the blood to the tissues and organs of the body
Drug Excretion
Elimination of the drug from the body
Drug Metabolism
The enzymatic biotransformation of a drug into metabolites
Drug Microsomal metabolizing system
Group of enzymes located primarily in the liver that function to metabolize (biotransformation) drugs.
Drug tolerance
Requirement of larger doses to be consumed in order to obtain the desired effects; decreased drug effect occurring after repeated drug administration
Enzyme induction
Increase in the amount of drug metabolizing enzymes after repeated administration of certain drugs
Enzyme inhibition
Inhibition of drug- metabolizing enzymes by certain drugs
First- pass metabolism
Drug metabolism that occurs in the intestines and liver during oral absorption of drugs into the systemic circulation
Half life
Time required for the body to reduce the amount of drug in the plasma by one half
Individual variation
Difference in the effects of drugs and drug dosages from one person to another
Intramuscular injection
Route of drug administration; drug is injected into gluteal or deltoid muscles.
Intravenous injection
Route of drug administration; drug is injected directly into a vein
loading dose
Initial drug dose administered to rapidly achieve therapeutic drug concentrations
Maintenance Dose
Dose administered to maintain drug blood levels in the therapeutic range; daily dosage of cardiac glycoside that maintains effective drug levels in the blood
Oral administration
Route of drug administration by way of the mouth through swallowing
Parenteral administration
Route of drug administration that does not involve the gastrointestinal tract
Delayed release products
usually tablets or capsules that are treated with special coatings so that various portions of the drug will dissolve at different rates. Delayed release products usually contain the equivalent of two or three single dose units. They are designed to produce drug effects over an extended time.
Suppositories
These are drugs mixed with a substance (cacao butter) that will melt at body temperature. Suppositories are intended for insertion into the rectum, urethra, or vagina
Parenteral Administration
-Administration of drugs by needle and syringe
Although some drugs are irritating to the stomach and may cause nausea, heartburn, and vomiting, administration of such drugs with sufficient amounts of water or with meals minimizes gastric irritation. However, food also delays drug absorption and therefore delays the onset of drug action.
Drug ionization
Most drugs exist in two forms: ionized and un-ionized. Like electrolytes (Na+ and CI-), ionized drugs are charged molecules because their atomic structure has lost or gained e-. The molecules then become either positively or negatively charged. I general, ionized drug molecules do not readily cross cell membranes. The un-ionized (uncharged) form of the drug is required in order for absorption to occur.
Drug formulation
Drugs must be in solution before being absorbed. Tablets and capsules require time for the dissolution to occur. For this reason, liquid medications are generally absorbed faster than the solid forms. Drug particles can be formulated into different sizes, such as crystals , micronized particles, or ultramicronized particles. The smaller the size of the drug particle, the faster the rate of dissolution and absorption.
Troches and Lozenges
These flattened tablets are allowed to dissolve in the mouth. Most commonly used for cold and sore throat
