Quiz 2 Flashcards
Pharmacokinetics process through the body
- Absorption
- Distribution
- Metabolism
- Excretion
Liver
Primary metabolism
Absorption
The movement of a drug from its site of administration into the blood
Rate determines
How soon effects will take place/how fast the body absorbs
Amount determines
How intense the effects will be
Factors affecting the process of absorption
-rate of dissolution
-surface area
-blood flow
-lipid solubility
-pH partitioning
-route of administration
Rate of dissolution
-rate something is dissolved
-the quicker the drug dissolves, the quicker the effects
Surface Area
-where the drug is absorbed
-the larger the surface area, the quicker the absorption of drug
Blood flow
Better blood flow = quicker, better absorption of drug
Lipid solubility
A cellular membrane that is made of lipids absorbs the drug more quickly
Routes of administration
-two groups
-enteral (GI Tract)= SLOWER!
-parenteral (outside GI tract)= FASTER!
Intravenous= FASTEST!
Distribution
The movement of drugs throughout the body
*dependent on blood flow!!!
Special factors/considerations in drug metabolism
-Age: metabolism & liver function slows down with age
-Nutritional status: weight/empty stomach
-First-pass effect: certain drugs that are completely metabolized by liver the 1st time they pass through
-competition between drugs
Excretion
-the removal of drugs from the body
-kidneys!!!*
-can exit through: bile, urine/feces, sweat/saliva, breast milk, expired air
Keep drugs between two important levels
-minimum effective concentration: barely effective
&
-toxic concentration
-in between: therapeutic range!!*
Drug half-life
-determines how often drug is administered
-amount of time for % of drug in body to decrease 50% *
Plateau
Semi-steady state of drug in body
Peak
-less than toxic
-usually 1-2 hours after the last dose
Trough
-greater than MEC
-seconds before giving meds
Loading and maintenance
Loading- load them up on a big dose/increase the drug in the body
THEN
Maintenance-small dose once a day, lower dose in body
Dose-Response Relationship
Relationship between the SIZE of an administered dose and the INTENSITY of the response produced
ED50
Average effective dose, dose effective in 50% of animals tested
LD50
Lethal affected dose
dose affected in 50% of animals
ED50 + LD50 =
Therapeutic index
