Drug Profile

Psyllium and methylcellulose for constipation

Psyllium and methylcellulose are laxatives that work by absorbing water and softening the stools in your intestine. The increased stool bulk stimulates the intestines to contract. Fiber that you get from food works exactly the same way. Because a diet high in fiber, combined with plenty of nonalcoholic liquids, has the same effect as psyllium and methylcellulose, it is not usually necessary to use these drugs. Eating high-fiber foods is preferable to taking psyllium or methylcellulose because these foods give you essential nutrients in addition to fiber. Psyllium and methylcellulose appear to be approximately equally effective.[1] Patients taking psyllium or methylcellulose appear to be less likely to pass gas than when taking another effective laxative, lactulose (CEPHULAC, CHRONOLAC).[2]

When do you really need to take a laxative? You should not take a laxative to “clean out your system” or to make your body act more “normally.” It is untrue that everyone must have a bowel movement daily. Perfectly healthy people may have from three bowel movements per week to three bowel movements per day.

If the frequency of your bowel movements has decreased, if you are having bowel movements less than three times a week, or if you are having difficulty in passing stools, you are constipated, but this does not mean that you need a laxative. It is better to treat simple, occasional constipation without drugs, by eating a high-fiber diet that includes whole-grain breads and cereals, raw vegetables, raw and dried fruits, and beans, and by drinking plenty of nonalcoholic liquids (six to eight glasses per day). This type of diet will both prevent and treat constipation, and it is less costly than taking drugs. Regular exercise—at least 30 minutes per day of swimming, cycling, jogging, or brisk walking—will also help your body maintain regularity.

If you are constipated while traveling or at some other time when it is hard for you to eat properly, it may be appropriate to take a laxative for a short time. The only types of laxatives you should use for self-medication are bulk-forming laxatives such as psyllium or methylcellulose or a hyperosmotic laxative such as lactulose. Bulk-forming laxatives usually take effect in 12 hours to three days, compared with docusate (COLACE, SURFAK), which takes effect one or two days after the first dose but may require three to five days of treatment. Even bulk-forming laxatives should only be used occasionally, if possible.

If you are on a special diet such as a low-salt or low-sugar diet, ask your doctor or pharmacist to help you choose a laxative without ingredients you are trying to avoid. Some laxatives contain sugar (up to half of the product), salt (up to 250 milligrams per dose), or the artificial sweetener NutraSweet.

Psyllium and Cholesterol

When added to the diet, psyllium is a safe, effective method of lowering cholesterol. If cholesterol remains high despite diet, add 10 grams of psyllium a day. Numerous studies have shown that five grams of psyllium twice a day can significantly lower total cholesterol and LDL cholesterol.[3] Psyllium, a naturally occurring vegetable fiber, is clearly safer than any of the cholesterol-lowering drugs. Because psyllium is a laxative that can cause dependence, discontinuing its use may result in a period of several days during which normal bowel movements do not occur.[4]

Allergies to Psyllium

Psyllium has been implicated in severe allergic reactions, typically by inhalation or by ingestion after exposure in the health care setting.[5]