when the receptor site becomes active. Example: After morphine agonist attaches to a Mu receptor, the receptor activates and produces analgesia, euphoria and respiratory depression.
Activation
is the strength of attraction between a drug and its receptor.
Affinity
is a measure of total systemic exposure to the drug.
Area under the curve
is the extent a substance or drug becomes completely available to its intended biological destination. Some factors that influence bioavailability include first-pass metabolism, route of administration, and chemical properties of the drug.
Bioavailability
is when two drugs are equal in the rate and extent to which the active pharmaceutical ingredient (API) becomes available at the site(s) of drug action.
Bioequivalence
(Drug metabolism) is the enzymatic alteration of drug structure. Most drug metabolism takes place in the liver.
Biotransformation
is a natural protective membrane that prevents central nervous system (CNS) from toxins and pathogens in blood.
Blood-brain barrier
increase the rate of hepatic metabolism decrease serum concentrations of other drugs metabolized by the same hepatic isoenzyme.
CYP enzyme inducers
decrease the rate of hepatic metabolism and increase serum concentrations of other drugs metabolized by the same hepatic isoenzyme.
CYP enzyme inhibitors
is the time it takes for the concentration of the drug in the plasma or the total amount in the body to be reduced by 50%.
Drug half-life
the rapid inactivation of certain oral drugs
First-pass hepatic metabolism
is the ability to dissolve through the lipid (fat) portion of a membrane.
Lipid solubility
All drugs cross the placenta to some degree but several factors determine the degree of placental transfer. Major determinants include lipid/water solubility, molecular weight, degree of ionization, and protein binding. Drugs that are lipid soluble, smaller have a low ionized fraction, and non-protein bound tend to cross the placenta to a greater degree.
Placental drug transfer
is the degree to which medications attach to blood proteins within the blood plasma. A drug's efficacy may be affected by the degree to which it binds. The less bound a drug is, the more efficiently it can traverse or diffuse through cell membranes.
Protein Binding
is a compound with little or no pharmacological activity that metabolizes inside the body and converts into a pharmacologically active drug compound.
Prodrug
is the substance on which an enzyme acts
Substrate
is the dosage range or blood plasma or serum concentration usually expected to achieve the desired therapeutic effect.
Therapeutic range