pharmacology — the study of medicines (or drugs) or the study of the biological effects of chemicals on the body. drug — a chemical that exerts an effect on the living body; a compound used in the prevention, treatment, diagnosis, or cure of a condition or disease. biosimilar — a drug that is synthetically produced and has similar properties to a specific biologic; although it does go through testing, it does not go through the same rigorous testing…. counterfeit drug — a product that is illegally manufactured or mislabeled regarding the identity or source and appears to be a genuine product; may be harmful to the client.