the time required for drug absorption, drug action, drug distribution in the body and metabolization and excretion of drug.
refers to the mechanism of action by which a drug causes its therapeutic effect
when increased amounts of a drug are needed to produce the desired effect, possibly due to increased enzyme levels related to enzymatic activity that develops over a period of time
an exaggerated response, occurs when two or more drugs are administered with the same effect on the body
either when two drugs produce an effect that is greater than what they usually produce when given alone or when one drug enhances the effect of another drug