Artem has a doctor of veterinary medicine degree.
Imagine a large bookshelf. In this bookshelf are thousands upon thousands of books. How would you classify them? You could do it by color, so all books of one color would be in one section together. You could classify them by author. Maybe you could classify them by genre. There are a lot of ways you can classify all of those books.
It's no different in the pharmaceutical and medical field. Pharmacological drugs can be classified in one of many ways. A drug class encompasses drugs that share something in common. One drug can, as a result, belong to more than one kind of drug class. This lesson can't cover all the possible classification schemes and criteria, but you will get a good sense of how it can be done.
By Organ System & Therapeutic Class
Drugs can be classified into the organ systems they affect the most. For instance, some drugs are called central nervous system (CNS) drugs, because that is the system they work on. The central nervous system is the brain and spinal cord, which send and receive messages through the entire body. Another example of this classification scheme would be a cardiovascular drug, a drug that affects the system of the heart and blood vessels. Some cardiovascular drugs act on the heart to slow it down, while others may cause the blood vessels to dilate (expand), and thus the blood pressure to drop.
Drugs that cause our blood pressure to drop are called antihypertensives. An antihypertensive is a therapeutic class of drug that treats hypertension (high blood pressure). In other words, we're classifying the drug not so much on the organ system the drug affects, but the actual therapeutic effect the drug has. Another example of a therapeutic class of medication is an analgesic, or pain reliever.
By Chemical Class & Legal Status
How does that analgesic work though? Well, this is where we get into the chemical class of the drug. In other words, chemical class refers to the way the drug biochemically works in our body to exert its effect. For example, an analgesic may be an opioid agonist, a drug that stimulates opioid receptors to produce pain relief. Chemical class may also literally refer to the chemical structure of the drug. For instance, the drug omeprazole, used to treat stomach ulcers, is chemically classified as a benzimidazole. This means it contains an organic compound called benzimidazole.
Another way drugs can be classified is according to their legal status. Some drugs are OTC, or over the counter. This means you can just go and buy them at the local store without a prescription. An example of this would be the blood thinner aspirin. Other drugs are prescription medications. This means they cannot be bought without a medical professional's authorization. An example of this would be an antibiotic such as penicillin.
Some drugs, namely those that have the potential for addiction, have very strict regulations and are thus categorized into one of five 'schedules'. For instance, schedule II drugs, the most addictive drugs that can still be legally prescribed, include the likes of a powerful pain reliever called fentanyl.
A drug class includes drugs that share something in common. However, one drug can be part of many different drug classes. Some classification schemes include:
- By organ system. Drugs that affect the brain and spinal cord, central nervous system (CNS) drugs, would be one example of this. So would cardiovascular drugs, those that target the heart and blood vessels.
- By therapeutic effect. Antihypertensives treat hypertension, or high blood pressure. Analgesics relieve pain.
- By chemical structure (benzimidazoles like omeprazole contain benzimidazole) or biochemical interactions (opioid agonists stimulate opioid receptors).
- Legal status. OTC, over the counter, drugs like aspirin can be bought without a prescription. Scheduled drugs, like fentanyl are the most tightly controlled of prescription medications.
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