The plasma half-life of a drug is the time necessary for the blood levels of a drug to drop to half of the equilibrium level. The drop in drug level might result from re-distribution and storage of the drug. The drop might result from metabolism and elimination of the drug. Drug metabolism occurs primarily in the liver, but also in blood plasma, kidneys, lungs, intestines, skin, and cell tissues at the site of the receptors. C. Drug actions 1.
Drug actions are the result of a chemical interaction with some part of the human organism.
Structurally non-specific and structurally specific drugs produce pharmacological actions. The interaction between drug molecules and human cells takes place in highly specific areas the receptors. The drug-receptor interaction i. The better fitting drug molecule bonded with the appropriate receptor producing the most desirable effect or action. If the drug binds inadequately to the drug receptor, there is no drug action or effect.