Answer:
Because of the diverse methods of classification, consumers can often be confused when their doctor calls a drug an ACE inhibitor, their pharmacist calls it an antihypertensive, and they read online that it is a vasoconstrictor. Ultimately, all of these terms can be used to describe the same drug used for the same purpose.
Explanation:
A drug class is a term used to describe medications that are grouped together because of their similarity. There are three dominant methods of classifying these groups:1
By their mechanism of action, meaning the specific biochemical reaction that occurs when you take a drug
By their physiologic effect, meaning the specific way in which the body responds to a drug
By their chemical structure
Based on these diverse classification methods, some drugs may be grouped together under one system but not another. In other cases, a drug may have multiple uses or actions (such as the drug fin a steride, which is used to treat an enlarged prostate or to regrow hair) and may be included in multiple drug classes within a single classification system.
This doesn't even take into account the drugs that are used off-label for reasons other than what they were approved. A prime example is levo thyroxine which is approved to treat hypothyroidism (low thyroid function) but is often used off-label to treat depression
