Is enteric aspirin "safe” and "easier” on the stomach than uncoated aspirin? The jury is still out …

Aspirin has long been known as an effective painkiller, but it's become as important for preventing stroke and heart attack as it is for preventing pain. Low-dose aspirin therapy helps prevent heart attack and stroke by keeping blood platelets from clumping together and forming dangerous clots. But this wonder drug also can produce gastrointestinal (GI) side effects, including an upset stomach. Long-term use of aspirin can cause GI bleeding and ulcers.

Enter enteric aspirin. Enteric aspirin, sometimes called safety aspirin, is coated so that it doesn’t dissolve in the stomach but instead passes through to dissolve in the small intestine, preventing GI upset. Many people use enteric aspirin for aspirin therapy, because they believe that it protects the GI system while providing the same cardiovascular benefits as uncoated aspirin.

Recently, however, there’s been some controversy over whether enteric aspirin is as good at preventing blood clots as uncoated aspirin. A recent European study of 131 cardiovascular patients published in Stroke found that a daily 75-mg enteric aspirin was less likely to fully inhibit platelet clumping than uncoated aspirin. Fifty-four percent of subjects taking enteric aspirin experienced incomplete inhibition compared with 8% of subjects taking uncoated aspirin. Heavier people were less likely to respond to any type of aspirin, leaving them especially at risk for incomplete platelet inhibition.

However, other studies have come to different conclusions. A study published in the American Heart Journal pitted 81-mg enteric aspirin against 81- mg chewable aspirin in 50 volunteers and found no difference. In a small study published in the American Journal of Cardiology, people who took an 81-mg enteric aspirin each day took longer to achieve full platelet inhibition, but after seven days of therapy, inhibition was at the same level as that of subjects who took regular aspirin.

What’s the verdict? The jury is still out as to whether coated or uncoated pills are better for aspirin therapy. For starters, experts are still uncertain about the optimum dosage and how best to measure aspirin’s anticlotting ability. A typical recommended dosage can range from 75-165 mg daily. Researchers working on the European study recommend taking a 75-mg uncoated aspirin (the lowest dose available in Europe; the American low-dose equivalent is an 81- mg uncoated aspirin). If you’d like to try a lower aspirin dose, try 81-mg children’s chewable aspirin.

If you experience an upset stomach after taking uncoated aspirin, you can talk to your doctor about the appropriate dosage of enteric aspirin. Raising your dosage may help ensure that you’re fully protected against blood clots, but it could also increase your risk of GI side effects unrelated to immediate stomach upset.

Bottom-line advice: You might assume that because enteric aspirin is marketed as "safe” and “easier on the stomach,” you can take it without ever experiencing any GI side effects. That’s not true -- enteric aspirin does prevent immediate stomach upset, but it doesn’t protect against the bleeding and ulceration that can occur after frequent aspirin use. Aspirin -- enteric or not -- hinders the production of prostaglandins that protect the stomach lining. This occurs no matter where the aspirin dissolves in the body. Whether you use enteric aspirin for aspirin therapy or just to ease pain, keep this fact in mind.

A last caution for those who are on aspirin therapy, enteric or otherwise: Nonsteroidal anti-inflammatory drugs (NSAIDs), such as ibuprofen products like Advil or Motrin, can interfere with aspirin’s anticlotting effect. People taking uncoated aspirin should avoid taking an NSAID for eight hours before and a half hour after taking their aspirin dose. It’s unclear how NSAIDs interact with enteric aspirin, but they may interfere more because enteric aspirin takes longer to be absorbed into the body, allowing no time for the body to absorb the drugs separately. If you must take other NSAIDs while you’re on aspirin therapy, ask your doctor about timing your doses of the two drugs.