Over-the-counter laxatives for constipation: Use with caution

Laxatives can help relieve and prevent constipation. But not all of them are safe for long-term use. Overuse of certain laxatives can lead to dependency and decreased bowel function.

If you've ever experienced the discomfort of constipation — perhaps while traveling or after a change in your diet — you may have considered over-the-counter laxatives. Laxatives are substances taken by mouth (oral laxatives) or in your rectum (an enema or suppositories) that relieve and prevent constipation. You can take oral laxatives in many different forms — liquids, tablets, wafers, gums, or powders that you dissolve in water. You take rectal laxatives in the form of suppositories or enemas.

How often you have a bowel movement varies, but a "normal" frequency ranges from as many as three a day to as few as two a week. Your body ordinarily needs no help to have them. But a poor diet, physical inactivity, pregnancy, illness or some medications can disrupt normal bowel function and cause constipation. Before turning to laxatives for relief, you may want to try the following lifestyle changes to help manage occasional irregularity:

Eat fiber-rich foods.
Drink plenty of fluids daily.
Get regular exercise.

How laxatives relieve constipation

Laxatives work in different ways, and the effectiveness of each laxative type varies from person to person. In general, bulk-forming laxatives, such as Metamucil and Citrucel are the gentlest on your body and safe to use long term, whereas stimulant laxatives, such as Ex-lax and Senokot, are the harshest and shouldn't be used long term. If you remain constipated despite changing your diet and exercise routine, your next choice may be a mild laxative.

Following are some examples of common types of laxatives. Other types of laxatives also exist. Talk to your doctor about what laxative may be right for you.

Type of laxative (brand examples)	How they work	Side effects
Oral hyperosmotics (Epsom salts, Phillips' Milk of Magnesia)	Draw water into colon from surrounding body tissues to allow easier passage of stool	Bloating, cramping, diarrhea, nausea, gas, increased thirst
Oral bulk formers (Citrucel, Metamucil)	Absorb water to form soft, bulky stool, prompting normal contraction of intestinal muscles	Bloating, gas, cramping, choking or increased constipation if not taken with enough water
Oral stool softeners (Colace, Surfak)	Add moisture to stool to allow strain-free bowel movements	Throat irritation, stomach or intestinal cramping
Oral stimulants (Ex-lax, Senokot)	Trigger rhythmic contractions of intestinal muscles to eliminate stool	Belching, cramping, diarrhea, nausea, faintness, urine discoloration
Rectal stimulants (Fleet Bisacodyl, Dulcolax)	Trigger rhythmic contractions of intestinal muscles to eliminate stool	Rectal irritation, stomach discomfort, faintness, cramping

In addition, oral laxatives such as those listed above may interfere with your body's absorption of some medications and food nutrients. Rectal laxatives do not have this effect.

Combination laxatives: Check labels carefully

Some products combine different types of laxatives, such as a stimulant and a stool softener. Combination products may not be any more effective than single-ingredient products. But they may be more likely to cause side effects because of their multiple ingredients. Carefully inspect labels to see how many types of laxatives a product contains.

Risks of laxative use

Interaction with medications
Your medical history and other medications you're taking may limit your laxative options. Laxatives can interact with blood thinners such as warfarin (Coumadin), antibiotics such as tetracycline and ciprofloxacin (Cipro), and certain heart and bone medications. Before using any laxative, read the label carefully. If you're not sure whether a particular laxative is right for you, ask your pharmacist or doctor. Don't exceed recommended dosages unless your doctor tells you otherwise.

Complicating conditions
Just because laxatives are available without a prescription doesn't mean that they're without risk. Laxative use can be dangerous if constipation is caused by a serious condition, such as appendicitis or a bowel obstruction. If you frequently use certain laxatives over a period of weeks or months, they can decrease your colon's natural ability to contract and actually worsen constipation. In severe cases, overuse of laxatives can damage nerves, muscles and tissues of the large intestine.

Unsafe if you're pregnant or under age 6
Don't give children under age 6 laxatives without a doctor's recommendation. If you're pregnant, seek your doctor's advice before using laxatives. Bulk-forming laxatives and stool softeners may be safe to use during pregnancy, but stronger laxatives can harm you or your baby. The stimulant laxative castor oil, for example, can cause womb contractions. If you've recently given birth, consult your doctor before using laxatives. Although laxatives are usually safe to use during breast-feeding, some ingredients may pass into breast milk and cause diarrhea in infants.

Don't be lax about laxatives

See your doctor if you have unexplained changes in bowel patterns or habits, if constipation lasts longer than seven days despite laxative use, or if constipation is accompanied by rectal bleeding. If you're dependent on laxatives, ask your doctor for advice on how to gradually withdraw from them and restore your colon's natural ability to contract.