How do i compare the term drug and the term medicine?

Drug

It is "a chemical substance used in the treatment, cure, prevention, or diagnosis of disease or used to otherwise enhance physical or mental well-being". Drugs may be prescribed for a limited duration, or on a regular basis for chronic disorders

Medicine

Medicine is a drug taken to cure and/or ameliorate any symptoms of an illness or medical condition, or may be used as preventive medicine that has future benefits but does not treat any existing or pre-existing diseases or symptoms.