Bulk-forming Laxatives: The bulk-forming laxatives have become the mainstay of the management of irritable bowel syndrome. They are particularly useful in this condition because in addition to relieving constipation, their hydrophilic properties help in the formation of stool that controls diarrhea as well.5
These products are contraindicated in individuals with intestinal ulcers or disabling adhesions. Failure to consume sufficient fluids with bulk laxatives can lead to esophageal obstruction and decreased drug efficacy. In a recent announcement the FDA required products containing bulking agents such as gums and mucilages to carry a warning label stating: “Taking this product without adequate fluid may cause it to swell and block your throat or esophagus and may cause choking. Do not take this product if you have difficulty in swallowing. If you experience chest pain, vomiting, or difficulty in swallowing or breathing after taking this product, seek immediate medical attention.”3
Hypersensitivity reactions can occur from inhaling the dust from psyllium. Patients should also check with the pharmacist for possible drug interactions. Psyllium husk is known to reduce the absorption of lovastatin and lithium, while bran is known to reduce the absorption of minerals such as iron, zinc and calcium.2
Stimulant Laxatives: Prolonged use of stimulant laxatives, in particular anthraquinone-containing products, has been frowned upon partly because of their demonstrated carcinogenic properties in rats and partly because they lead to laxative dependency and loss of normal bowel function.1 Anthraquinone derivatives, after four to 13 months of use, are known to cause melanosis coli, an accumulation of dark pigment mainly in the cecum and rectum. This pigmentation disappears three to six months after the anthraquinone drug use is discontinued.3 Senna use in pregnancy is not known to produce any adverse effects. However, a small percent of breast-fed infants are known to suffer from diarrhea, and breast milk is often discolored due to the presence of anthraquinones.2 Patients should be forewarned that compounds found in senna may color acidic urine yellowish-brown and alkaline urine reddish-violet.1 Castor oil is rarely used these days because of its adverse effects of cramping. However, it is employed to empty the gastrointestinal tract prior to proctoscopy or X-ray studies of the gastrointestinal tract.5 Stimulant laxatives and especially castor oil should be avoided by pregnant women as these are known to induce premature labor.1
Dieter’s Tea Containing Anthraquinone Products: The FDA has received reports including deaths of four women in which dieter’s teas may have been a contributing factor. These products available in health food stores and through mail-order catalogs are used for weight loss based on belief that increased bowel movements will prevent absorption of calories, thus preventing weight gain.
Laxative induced diarrhea does not significantly reduce absorption of calories because the laxatives do not work on the small intestine, where calories are absorbed, but on the colon, the lower end of the bowel.
The names of many of these teas suggest the products can promote weight loss, although the label does not state how this is possible. The label also may fail to state that these herbal products contain herbs with laxative properties, which, when misused, can create serious problems. Some products have suggestive names such as “dieter’s,” “diet,” “trim,” and “slim,” in their names.