Pharmacology, or the study of drugs and medications, is a complicated subject. One of the ways to make it easier to understand is to have a good knowledge of drug classification, or the system by which various drugs are grouped together.
How Are Drugs Classified?Drugs are categorized in a variety of different ways. In the pharmaceutical industry, drugs are grouped according to their chemical activity or conditions that they treat. There are many reasons to classify drugs, ranging from understanding the usefulness of particular types of drugs to formulating treatment plans based on chemically similar drugs. In the world of illicit and abused drug use, there are essentially 7 different types of drugs. Each has its own set of characteristics, effects, dangers, and side effects.
Drug categories include the following:
For Drug Enforcement Agency (DEA) purposes, these drug classifications are further distilled to 5 categories. The DEA also refers to these as schedules, and these schedules depend on the drug’s accepted and authorized medical use or the drug’s abuse and dependency potential. The abuse rate of a drug is determining factor when assigning a schedule. For example, Schedule I drugs are shown to have a high abuse rate and the potential to create significant psychological and physical dependence.1
The DEA defines physical dependence as developing when the body becomes habitually in need of a drug. Physical dependence is often exhibited both in the development of a tolerance to a drug and in the withdrawal effects that might occur if a person stops using the drug. When a person builds a tolerance to a particular substance, it takes an increasingly larger amount of the substance to experience the same effects as once occurred with smaller amounts. Withdrawal develops with prolonged or excessive use and is experienced when a drug is sharply reduced or stopped all together. Often, withdrawal symptoms are excruciating and difficult to manage, which further encourages the drug use.