How Vioxx Works

The so-called “super aspirins” of the late 1990s, including Vioxx, Bextra, and Celebrex, promised to provide much-needed relief to the thousands of arthritis sufferers without the danger of ulcers that had long been associated with traditional pain killers. To achieve this, the “super aspirins” targeted a specific enzyme within the body, while preserving the body’s ability to protect its own stomach from the drug.

How NSAIDs Work

NSAIDs treat pain by preventing the body’s production of a chemical called prostaglandin. Prostaglandin is a lipid that is found in the blood vessels, kidneys, stomach, and most other organs. Prostaglandin has multiple effects within the body, and is sometimes sub-classified into “good” and “bad” prostaglandin. Prostaglandin is formed in the body by the reaction of fatty acids with the enzyme cyclooxygenase (COX), and it is this enzyme that is directly targeted by Vioxx.

COX Inhibitors

Vioxx is called a selective COX-2 inhibitor because it specifically targets one form of the COX enzyme, COX-2. COX-2 is responsible for the production of “bad prostaglandin,” which causes pain and inflammation, while the COX-1 enzyme is responsible for the production of “good prostaglandin,” which creates a protective mucous lining in the stomach and intestines.

Traditional NSAIDs are considered non-selective COX inhibitors because they target the COX-1 and COX-2 enzymes almost equally. While non-selective COX inhibitors do prevent the formation of bad prostaglandin associated with pain and inflammation, they also prevent the formation of good prostaglandin, which has protective effects. This is why non-selective NSAIDs are normally associated with gastrointestinal side effects such as peptic ulcers.

How Super Aspirins Differed from the Alternatives

Steroidal Anti-Inflammatory Drugs

Steroids are used to treat a variety of conditions, including inflammation, severe allergies, and difficulty regulating immune or digestive system functions. NSAIDs, by definition, do not contain steroids. The numerous associated side effects make steroids undesirable and dangerous for extended use, and they are rarely used to treat chronic conditions.

Traditional Pain Killers

Many traditional over-the-counter pain killers are NSAIDs. Aspirin and ibuprofen-based drugs like Motrin and Advil are non-selective NSAIDs, which means they treat pain by inhibiting the body’s production of prostaglandin.

Acetaminophen-based drugs, like Tylenol, are used for pain and fever, but they do not treat inflammation so they are not NSAIDs. These drugs treat pain by affecting prostaglandin production, but they do not specifically inhibit the COX enzyme. The mechanism of action for these types of drugs is not completely understood.

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