Laxative Lowdown


From the publishers of the New England Journal of Medicine



In late summer, the US Food and Drug Administration proposed banning the active ingredient in Ex-Lax and similar nonprescription laxatives due to "long-term safety concerns." The request grew from research showing that rats and mice fed the chemical, phenolphthalein, for two years developed a variety of tumors. No human studies have revealed any cancer related to phenolpthalein, the agency noted, and the rodents consumed up to 100 times the dose recommended for humans. Even so, the FDA concluded that there was a "potential cancer risk to people who use this ingredient at higher than recommended doses or for extended periods of time."

Novartis, the Swiss pharmaceutical giant that makes Ex-Lax, promptly volunteered to stop selling laxatives with the chemical in the US and announced plans to introduce a reformulated version with senna, a natural stool softener, this fall. But the company reiterated its belief that the chemical was "safe and effective" and presented no risk to users.

Should you be concerned if you've used Ex-Lax for years? Is a laxative a good option for coping with constipation?

--The Editors


The Physician's Perspective
Harry Greene, MD

Phenolphthalein products such as Ex-Lax and other drugstore brand laxatives have been around for 100 years and widely used since the 1960s. We know of no reports of human cancer caused by phenolphthalein. The lack of evidence of a cancer correlation in humans from a compound that has been on the market for years and used by thousands of people suggests that the risk, if real, must be extremely small. If you are still concerned because of excessive or chronic use, be sure to follow the standard recommendations for colon cancer screening ("Colon Cancer Genetics"). The broader issue is whether someone should take a laxative in the first place. And, with the availability of other natural agents, why use chemicals at all?

In Western society, adults average three bowel movements per week—far less than the daily regularity that many people expect. Everyone is different, and often what a patient thinks is a problem only reflects his or her perception of what is normal. Constipation is defined as a decrease in bowel movement frequency accompanied by hard bowel movements and difficulty evacuating stool.

Alterations in the muscle contractions that move waste through the intestines and the amount of water removed from the waste during this process can affect normal bowel function. Constipation can be brought on by dehydration from air travel or visiting a desert region without adequate fluid replacement. Constipation can occur in seniors because their sense of thirst may be blunted, leading them to drink less water than they need.

People don't realize that medications are one of the chief causes of constipation, especially cough syrup containing codeine. Antidepressants, sedatives, aluminum antacids and histamine-blocker antacids, calcium-channel blockers, oral iron supplements, and opiate analgesics all are culprits—although no one should stop taking a prescription without a doctor's supervision.

For an otherwise healthy person who comes to me complaining of constipation, I'd first ask about medications or recent dehydration. Hemorrhoids or anal fissures also can cause a person to unwittingly avoid painful defecation. When constipation continues for two weeks despite behavior changes, a doctor must rule out colon cancer, an underactive thyroid, Parkinson's disease, and other problems that may affect the nervous system supplying the bowel. But first, I recommend these steps:

bulletDrink more water, increase dietary fiber with more fruits and vegetables (especially corn and salads), and a high-fiber cereal for breakfast. Consider daily exercise, which can stimulate bowels. Set aside a daily time for elimination.
bulletTry a bulk former containing psyllium, a vegetable fiber ground into powder that you mix with water and drink daily. (Metamucil is an example.)
bulletIf constipation persists, I suggest the most gentle laxatives. Senna products are a natural way to soften stool, and milk of magnesia increases intestinal water content without irritating the colon wall as castor oil does.
bulletI tend not to recommend products with phenolphthalein; these work by irritating the bowel, which responds by drawing in water. The resulting diarrhea can lead to a loss of potassium and other electrolytes. Repeated use diminishes muscle tone and the intestine's ability to function on its own, which can lead to laxative dependence.
bulletAvoid enemas, which also may deplete electrolytes.
bulletIf bowel habits don't return to normal within two weeks, if they recur, or if there is blood in the stool, seek an examination (which may include sigmoidoscopy or colonoscopy) to rule out other problems.



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