What is Enteric-Coated Aspirin?

An enteric-coated aspirin is a tablet of acetylsalicylic acid (ASA), a common pain reliever, that has been covered by a thin layer of material designed to avoid irritation to the stomach lining. This form of the aspirin medication is helpful to those with sensitive stomachs or those on an aspirin regimen. The coating is also helpful to some people who have difficulty swallowing pills.

Acetylsalicylic acid (ASA), originally extracted from willow plants, is known in much of the world as aspirin. Bayer AG of Germany patented Aspirin™ in 1897. In countries in which Bayer still owns the trademark Aspirin™, the term ASA is used to refer to the generic drug.

Aspirin is known to cause stomach irritation in some people, particularly if regular, daily consumption of the pill is required. Some heart and circulatory patients are prescribed a low-dose, enteric-coated aspiring a day. Symptoms of aspirin-induced stomach irritation include stomach pain, nausea, and gastric reflux. Often, the ingestion of an acid-absorbing tablet does little too relieve the symptoms. In severe instances, gastrointestinal bleeding occurs.

The coating of the enteric-coated aspirin is designed to be stable in the low pH conditions of the stomach. The pH, or acidity measurement, of the stomach is approximately 3, while the small intestine, where absorption of the drug needs to occur, has a pH of 7 to 9. The coating material consists of waxy compounds, polymers, or sometimes fibers. Efficacy is determined by placing coated pills in a liquid with a pH of 1.2 for 20 minutes and then moving the pills to a liquid of pH 6.8. A successful enteric-coated aspirin tablet would not dissolve in the first liquid but would in the second.

The smoothness of the enteric-coated aspirin also allows the pill to be swallowed easily. While aspirin is not a large pill, the tablet can fall apart in the mouth, leaving a bitter taste. This type of aspirin may be taken with or without food as well.

Aspirin, in addition to its pain-relieving abilities, also has an anti-platelet effect. Platelets are used by the body to repair the walls of the blood vessels. Aspirin, with its anti-coagulant effect, should not be taken with other drugs classified as “blood-thinners.” Some studies show that a single aspirin administered shortly after a heart attack can prevent a second heart attack and help prevent cardiac damage. Regular aspirin, rather than an enteric-coated aspirin, is preferable for quick absorption. Enteric-coated aspirin is designated as EC aspirin or aspirin EC.