Medical Drugs & Chemistry: Classification & Mechanism of Action

Instructor: Korry Barnes

Korry has a Ph.D. in organic chemistry and teaches college chemistry courses.

The primary focal point of this lesson will be on the subject of the chemistry of medical drugs. Our main topics of discussion will include how they are classified and their mechanism of action.

Can't Live Without Them

When you hear the term medical drug what's the first thing that comes to your mind? Perhaps you think about a simple medication like Tylenol that's used for the relief of mild to moderate pain. Or maybe you think of something more exotic like Harvoni which has recently come on the market as a powerful drug for the treatment of patients with Hepatitis C.

Regardless of what your mind goes to when you think about medical drugs, there's no doubt that drugs play an important role in virtually everyone's life in some way, shape, or form. In our lesson today, we are going to be learning about the chemistry of some of the more important medical drugs by studying their classification and how they work by looking at their mechanism of action. Let's get started!

Nonsteroidal Anti-Inflammatory Drugs

We will begin by discussing a class of drug called nonsteroidal anti-inflammatory drugs, which are commonly referred to as NSAIDs. NSAIDs represent a class of drugs whose primary functions are to help reduce pain, fevers, and inflammation. As their name implies, these drugs are not derivatives of steroids, which also have anti-inflammatory and pain relieving properties.

Example of an NSAID

Probably one of the most common over-the-counter NSAIDs is a medicine called naproxen, which is marketed under the brand names Aleve and Naprosyn. Naproxen is an aromatic compound that contains two benzene rings fused together, and it also contains carboxylic acid and ether functional groups.

The structure of naproxen, a common NSAID

Mechanism of Action of Naproxen

Naproxen induces its anti-inflammatory effects by acting as a reversible inhibitor of the enzymes known as cyclooxygenase 1 (COX-1) and cyclooxygenase 2 (COX-2). These enzymes are responsible for producing prostaglandins, which themselves are signaling molecules that cause inflammation in the body. By inhibiting these enzymes, naproxen halts the production of prostaglandins which in turn inhibits inflammation.

Drugs that Target Tubulin

Another important class of drugs are those that target a biomolecule called tubulin. These types of drugs have received incredible attention from the synthetic community for their application as drugs that combat various types of cancer.

Example of an Anti-Tubulin Drug

Probably the most publicized compound that targets tubulin is called paclitaxel and is marketed under the trade name Taxol. Paclitaxel is actually a natural product that was isolated from the Pacific yew tree back in the early 1970s. It's a quite complicated organic compound with several rings and various other functional groups present.

Paclitaxel is a natural product that is a potent tubulin-targeting compound

Mechanism of Action of Paclitaxel

The family of tubulin proteins inside the cytoskeleton of eukaryotic cells are extremely important and play a major role a variety of cellular processes such as cell replication. Specifically, microtubules serve to form what's called the mitotic spindle which aids in the segregation of chromosomes during cell division.

Compounds like paclitaxel can selectively target a cell's microtubules and thus interfere with cell replication. This is very important since cancerous cells are always rapidly dividing and multiplying to form tumors.

Antiviral Drugs

Sometimes we get viral infections and need to combat these infections with what are called anti-viral drugs. These types of drugs enjoy a wide range of activity and depending on the specific drug, have different mechanisms of action in which they fight the virus.

Example of an Anti-Viral Drug

Have you ever gotten the flu and went to the doctor for medicine? If so, the doctor probably prescribed the drug oseltamivir, which is marketed under the trade name Tamiflu. Tamiflu is most commonly prescribed to treat both influenza A and influenza B, the common forms of the flu. Tamiflu contains contains amine, ester, and amide functional groups.

Oseltamivir (Tamiflu) is an anti-viral drug used to combat patients with the flu

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