Every year, people around the world take an astonishing 3.8trn doses of medicine. Most of them are swallowed rather than injected or inhaled, because the oral route is the easiest, safest, and most familiar way to take a drug at home.
But even something as routine as swallowing a pill can sometimes cause harm, writes Professor of Anatomy Adam Taylor in The Conversation.
He writes:
Pill-induced oesophagitis occurs when a tablet or capsule gets stuck in the narrowing at the lower end of the oesophagus, where it meets the stomach. If a pill lodges there and begins to dissolve, it can release its active ingredients directly on to the delicate tissue.
These substances are often acidic or alkaline, and that chemical burn can quickly cause pain and inflammation.
Although considered uncommon, studies suggest it has an estimated incidence of 3.9 per 100 000 population per year. It may be under-reported because mild cases often resolve without medical attention.
The inner surface of the oesophagus is lined with a thin, specialised mucosal layer that helps food pass smoothly into the stomach. By contrast, the stomach’s mucosa produces mucus to protect against acid, which is essential for digesting food and destroying microbes.
When a pill dissolves too early, it exposes the unprotected oesophageal lining to caustic substances that it was never designed to handle, leading to irritation, inflammation and sometimes ulceration.
Symptoms can mimic heartburn or indigestion but are usually sharper and more localised, with pain felt behind the breastbone. Some people experience pain when swallowing or a sudden hoarseness or change in voice.
In rare and untreated cases, the damage can deepen, allowing ulcers to rupture through the oesophageal wall, leading to severe infection or even death.
Middle-aged women are most often affected, partly because they are statistically more likely to take regular medication, including treatments for bone health.
Older adults are also at increased risk because age-related changes in oesophageal motility make it harder for pills to pass smoothly into the stomach. People with conditions that alter the shape or position of nearby organs – such as an enlarged heart or thyroid – may also be at higher risk.
Children are less commonly affected, but they have their own unique risk factors. Difficulty swallowing pills, smaller anatomy, and inexperience can all increase the likelihood of a tablet becoming lodged.
Medications most likely to cause damage
Several well-known medicines can irritate or injure the oesophagus if they linger there. Bisphosphonates, used to treat osteoporosis, are a leading cause, and this may explain why women are more commonly affected. Around one in 10 post-menopausal women in the UK are prescribed oral bisphosphonates.
Tetracycline antibiotics, used for a wide range of infections, carry similar risks. Aspirin and ibuprofen, two widely used non-steroidal anti-inflammatory drugs, can also induce oesophagitis, though they work differently by disrupting the protective barrier rather than causing a direct chemical burn.
Even over-the-counter so-called natural products, such as dietary supplements and vitamins, can cause problems. Caffeine tablets, potassium chloride supplements, L-arginine, and high-dose vitamin C or vitamin E pills have all been linked to pill-induced esophagitis.
Caffeine, in particular, can damage the gastrointestinal lining even without becoming stuck.
Concentrated doses stimulate acid production and increase gut motility, which can weaken the protective mucosal barrier and lead to inflammation.
Potassium chloride is a mineral supplement that replaces potassium lost through illness or medication, but its large, dense tablets can physically irritate the oesophagus if they dissolve before reaching the stomach.
L-arginine, an amino acid supplement, and vitamin C are chemically alkaline and acidic, respectively, so both can burn or inflame the lining if trapped. Vitamin E, often packaged in smooth gel capsules, can also linger and leak irritating oils.
Gelatin-based soft capsules carry their own risk. Because gelatine is hygroscopic, meaning it absorbs moisture from its surroundings, it can soften and become sticky. This increases the chance that a capsule will cling to the oesophageal wall rather than pass smoothly into the stomach.
When that happens, the capsule’s contents may be released directly on to sensitive tissue, causing local irritation or ulceration.
Prevention and treatment
Most mild cases resolve within a few days or weeks once the offending medication is stopped. Short courses of antibiotics, for instance, rarely cause lasting harm.
There are, however, simple steps to prevent oesophagitis from developing in the first place. Always take pills with a full glass of water – about 200 ml – to ensure they reach the stomach.
Take them on an empty stomach if advised, and remain upright for at least 30 minutes afterward. This helps prevent regurgitation and gives the medication time to dilute in the stomach.
For drugs like bisphosphonates, your doctor may recommend switching to a different formulation or a non-oral route, such as injections, which are more potent but can bring other side effects.
If long-term treatment is necessary, additional medications may help protect the digestive tract. Proton pump inhibitors reduce stomach acid and support healing, while sucralfate forms a soothing barrier over irritated tissue.
Any medications that are likely to cause esophagitis should be swallowed one at a time, cut into smaller pieces if they’re large.
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Pill-induced esophagitis is a painful but preventable condition. Simple habits like drinking plenty of water, sitting upright, and following medication instructions carefully can dramatically reduce the risk.
Adam Taylor, Professor of Anatomy, Lancaster University
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