Health officials have issued a stark warning regarding the long-term use of acid reflux medications, specifically proton pump inhibitors (PPIs) like omeprazole, citing an increased risk of developing a potentially fatal bacterial infection known as Clostridioides difficile, or C. diff. Acid reflux, characterized by stomach acid repeatedly flowing back into the gullet, is a common cause of indigestion and heartburn.

PPIs are among the most frequently prescribed medications in the UK for these conditions, with 73 million NHS prescriptions dispensed in England during 2022-23, costing £190 million. These drugs work by reducing the amount of acid in the stomach, thereby relieving symptoms such as heartburn, stomach ulcers, and acid reflux. However, this acid reduction can disrupt the natural balance of bacteria in the gut, making individuals more susceptible to C. diff infection. The NHS explicitly warns against taking omeprazole for longer than two weeks without a prescription due to these concerns.

C. diff is a highly contagious bacterium that initially infects the bowel, causing severe diarrhoea. While it usually lives harmlessly in the gut, its proliferation due to altered gut conditions can lead to life-threatening complications. These include sepsis, a dangerous over-reaction of the immune system to an infection, and peritonitis, a deadly infection if the bacteria spreads to other areas of the abdomen. C. diff is responsible for the death of up to one in five patients who fall ill with it.

Experts have long cautioned against relying on acid-suppressing medicines for simple heartburn. Pharmacist Deborah Grayson emphasized that while omeprazole can be beneficial for conditions like gastritis or oesophageal erosion, its long-term use for uncomplicated heartburn can have significant detrimental impacts on the body. Stomach acid plays a crucial role in digestion, activating enzymes like pepsin to break down proteins, softening food, and protecting against harmful microbes.

Reduced stomach acid can compromise the gut's natural defense barrier, increasing vulnerability not only to C. diff but also to other infections such as campylobacter and small intestinal bacterial overgrowth (SIBO), which can cause further gastrointestinal symptoms and serious complications. The NHS advises consulting a GP if symptoms worsen or do not improve after two weeks of non-prescription use.

The warning coincides with a significant surge in C. diff cases, which increased by a third in just one year, with experts pointing to an overwhelmed NHS. The UK Health Security Agency (UKHSA) reported 29.5 cases per 100,000 people in 2023-24, representing a 33% rise since 2020-21 and the highest level in over a decade. C. diff is recognized as the leading cause of healthcare-associated infections, spread through spores in infected patients' faeces that can survive for extended periods on surfaces.

Symptoms of a C. diff infection include diarrhoea, high temperature, loss of appetite, nausea, and stomach pain. Individuals experiencing diarrhoea after recently taking antibiotics, bloody diarrhoea, or diarrhoea lasting a week or more are advised to contact NHS 111 or their GP. Furthermore, research indicates that up to 40% of patients do not respond to PPIs, rendering the drug ineffective in those cases.