Certain alkaline mineral and medicinal waters can weaken the protective coating of enteric-coated medications within minutes, potentially making them less effective, according to a new study by pharmacists at the Semmelweis University.
The research, published in the journal Pharmaceutics, found that if an active ingredient dissolves too early in the stomach instead of the intestines, it may reduce or even completely eliminate the effectiveness of some reflux medications, stomach-protecting drugs, psychiatric treatments, and anti-inflammatory painkillers.
Researchers examined how different liquids affect enteric-coated medicines. They analyzed 22 commonly consumed beverages and conducted detailed laboratory tests on seven of them, including several mineral and medicinal waters, tap water, filtered water, and apple juice.
The most significant effects were observed with alkaline bottled waters containing high levels of minerals. According to the researchers, not only the water’s alkalinity but also its high mineral and ion content may contribute to the faster breakdown of the protective coating. This effect was particularly pronounced with some medicinal waters.
Tests showed that in certain medicinal waters, the enteric coating began to deteriorate after just five minutes. After 15 to 30 minutes of exposure, more than 90 percent of the active ingredient was released prematurely. In contrast, more acidic liquids such as apple juice preserved the coating much more effectively.
Enteric-coated medicines are specifically designed so that the active ingredient is released in the intestines rather than the stomach. This is necessary because some drugs can be broken down by stomach acid, while others may irritate the stomach lining. Such coatings are commonly used on medications for reflux, inflammation, pain relief, and digestive enzyme supplements.
Nikolett Kállai-Szabó, associate professor at the university’s Faculty of Pharmaceutical Sciences and the study’s senior author, noted that healthcare professionals generally consider it obvious that medicines should be taken with plain tap water. However, with the wide variety of mineral and medicinal waters available today, this is not always clear to patients.
The researchers also reviewed the prescribing information for 103 enteric-coated medicines. Of the patient information leaflets examined, 42 did not specify what type of liquid should be used when taking the medication. Another 31 referred only generally to “liquid,” while 21 mentioned “water” without further clarification. Only nine provided specific guidance, such as recommending apple juice or a mildly acidic beverage.
Adrienn Demeter, a PhD student at the Faculty of Pharmaceutical Sciences and the study’s lead author, highlighted that the issue may be particularly important for people who open hard capsules due to swallowing difficulties and mix the contents into liquids, yogurt, or applesauce. Elderly people, children, and patients with temporary throat pain often find themselves in this situation.
According to pharmacists, many patients are unaware that the liquid used to take medication can influence the success of treatment.
The researchers emphasized that the findings do not suggest that mineral or medicinal waters are harmful in themselves. The key message is that enteric-coated medicines should preferably be taken with plain water, and patients should consult their doctor or pharmacist before opening capsules or splitting tablets.
(MTI)
