Drug Profile

Buffered aspirin (ASCRIPTIN, BUFFERIN) is aspirin with a “buffer” or “acid neutralizer” added to it. Advertisements for buffered aspirin claim that it relieves pain faster than plain aspirin because it is absorbed better, and also that it is less irritating to the stomach and intestines than plain aspirin. However, there is no evidence to support these claims.

The amount of buffer in buffered aspirin is very small — only a fraction of the amount found in even one teaspoon of many antacids. A Food and Drug Administration (FDA) advisory committee found that although buffered aspirin may be absorbed more quickly than plain aspirin, it does not provide much faster pain relief. The committee also found no evidence that buffered aspirin is any gentler to the stomach than plain aspirin.

For patients who take aspirin only occasionally, plain generic aspirin is better than buffered because it is much less expensive and relieves pain just as quickly.

Diflunisal (DOLOBID) and salsalate (DISALCID) should not be used because they have no advantage over plain aspirin. ALKA-SELTZER, a brand of buffered aspirin, should not be taken by anyone whose salt (sodium) intake has been limited.

Adverse effects

Patients who frequently use medication to relieve headache pain may develop a condition known as medication overuse headache (MOH). According to a 2004 review published in Lancet Neurology,[1] there is substantial evidence that all headache drugs can cause MOH in patients who use these drugs excessively.

Aspirin-induced asthma can occur in asthmatic patients who are sensitive to aspirin or other nonsteroidal anti-inflammatory drugs (NSAIDs). It typically involves the onset of asthma 30 minutes to three hours after taking aspirin or NSAIDs. Many aspirin- and NSAID-containing products are available without a prescription and many asthmatic patients may be unaware of their sensitivity to aspirin.[2]

Interactions

Studies suggest a possible harmful interaction between NSAIDs and a class of osteoporosis drugs called bisphosphonates. Patients need to be alert to the fact that the combination can result in an increased risk of ulcers and other gastrointestinal adverse effects. Read more in the July 2010 issue of Worst Pills, Best Pills News.

Several studies have shown that combining aspirin or another NSAID with an oral anticoagulant (blood thinners for preventing blood clots) increases the risk of bleeding compared with using an anticoagulant alone.[3],[4]

Studies show...

A recent meta-analysis (a study that combines data from many other studies) compared the risks and benefits of adding aspirin therapy to the drug regimen of patients who were already taking an oral anticoagulant therapy such as warfarin (COUMADIN), including patients with atrial fibrillation or with mechanical heart valves. This study demonstrated that there is little support in the published literature for the common clinical practice of adding aspirin to oral anticoagulant therapy except in select patients with a mechanical heart valve. The additional risk of bleeding was not thought to be warranted.

The Archives of Internal Medicine published a meta-analysis in 2012 in which the authors aimed to assess whether the benefits of aspirin for those without known cardiovascular disease would outweigh aspirin’s increased risk of serious bleeding. The study found that aspirin, taken daily or every other day in low doses for primary prevention of cardiovascular death in patients without existing cardiovascular disease, was not effective in reducing cardiovascular death or death from cancer. Aspirin did, however, increase clinically important bleeding events.[5]

In 2021, Expert Opinion on Pharmacotherapy published an article warning that aspirin was associated with an increased risk of bleeding. The risk of bleeding may outweigh the benefit of preventing heart disease.[6]

Regulatory actions surrounding buffered aspirin

2005: The FDA requested that manufacturers of NSAIDs, both prescription and over-the-counter, revise their labeling to include the potential for the increased risk of cardiovascular events (read the information noted with COX-2 inhibitors) and gastrointestinal bleeding (see above). The FDA also required a Medication Guide to be provided to patients with each prescription dispensed.

2020: The FDA and Health Canada (an agency in Canada similar to the FDA) warned that use of NSAIDs at about 20 weeks or later in pregnancy rarely causes serious kidney problems in an unborn baby.[7],[8] These kidney problems can lead to oligohydramnios, a condition in which there are low levels of amniotic fluid surrounding the baby. Amniotic fluid normally provides a protective cushion and plays an important role in the development of a baby’s lungs, digestive system and muscles. Oligohydramnios in turn can lead to decreased range of motion in a baby’s arms and legs and delayed lung maturation.