Study shows long-term laxative use should be monitored

Regular use of laxatives over long periods may carry risks and should be guided by medical advice, experts are saying.

According to Western Sydney University Associate Professor and Clinical Academic Gastroenterologist, Vincent Ho, laxatives can be effective, but prolonged use should be monitored by a doctor, even though serious complications are uncommon.

Laxatives are widely available without prescription and are commonly used to treat constipation, particularly among older people. While they can be effective, health professionals recommend that prolonged use be monitored by a doctor.

There are five main types of oral laxatives. Bulk-forming laxatives, such as fibre supplements, absorb water to create softer stools and stimulate normal bowel contractions. Osmotic laxatives draw water into the colon to ease the passage of stool. Stool softeners allow fat and water to mix into hard stool, while stimulant laxatives trigger rhythmic contractions of bowel muscles. Lubricant laxatives coat the bowel to soften stool.

Before starting medication, dietary and lifestyle changes – including increasing fibre intake, drinking more water and exercising – are typically recommended. Gentler options such as bulk-forming laxatives or stool softeners are often suggested first if constipation persists.

Doctors also advise medical consultation before beginning laxatives because constipation can sometimes signal more serious underlying conditions, particularly when accompanied by symptoms such as rectal bleeding. Laxatives may also interact with other medications.

Concerns about a so-called “lazy colon” linked to long-term laxative use have circulated for decades. The idea stems from a 1960s case report describing bowel changes in a patient who had used stimulant laxatives for more than 40 years. However, later reviews of published cases found no confirmed instances of cathartic colon and suggested earlier cases may have involved now-obsolete treatments.

A further review of studies on stimulant laxative safety found many were limited by small sample sizes and other confounding factors, concluding there was no strong evidence that chronic use damages the gut.

Despite this, experts say there are other reasons to avoid regular or excessive use without supervision. Laxative abuse – defined as frequent or repeated use for weight loss – is associated with symptoms including diarrhoea, abdominal cramps, nausea, vomiting and weight loss.

Excessive diarrhoea can also disrupt the body’s electrolyte balance. Potassium loss is a particular concern and can lead to muscle weakness, heart complications and changes in heart rhythm. In extreme cases, dangerously low potassium levels can cause cardiac arrest.

A 2020 systematic review of case reports found laxative abuse could lead to cardiac complications ranging from mild to severe. Other electrolytes such as calcium and magnesium may also be affected, sometimes resulting in painful muscle contractions or kidney problems.

However, researchers note that when taken at recommended doses, the risk of serious electrolyte complications is extremely low.

Large UK population studies have also found associations between regular laxative use and increased risks of depression and dementia. One proposed explanation is that chronic laxative abuse could alter the “microbiome-gut-brain axis”, the communication pathway between gut bacteria and the brain.

Ho said laxative abuse is commonly linked to eating disorders, prompting calls for comprehensive mental health assessment when misuse is identified.

Health professionals emphasise that laxatives remain an important and effective treatment for chronic constipation. But they advise people to seek medical guidance before starting or continuing long-term use, particularly if they have other medical conditions or take additional medications.

IMPORTANT LEGAL INFO This article is of a general nature and FYI only, because it doesn’t take into account your personal health requirements or existing medical conditions. That means it’s not personalised health advice and shouldn’t be relied upon as if it is. Before making a health-related decision, you should work out if the info is appropriate for your situation and get professional medical advice.