Laxatives: OTC Products for Constipation

What types of OTC products treat constipation?

Over-the-counter (OTC) products are medicines you can buy without a prescription from your doctor. Many different kinds of products are advertised to relieve constipation, including bulk-forming laxatives, lubricants, stool softeners, saline laxatives, stimulant laxatives and combination medicines.

How do laxatives work?

Bulk-forming laxatives draw water into the stool to create large soft stools. The larger stools help trigger the bowel to contract and move the stools out. Examples of bulk-forming laxatives include psyllium (one brand name: Metamucil), polycarbophil (one brand name: FiberCon) and methylcellulose (one brand name: Citrucel). Start slowly and make sure to drink plenty of fluids while taking bulk-forming laxatives. Gradually increase how much you use to reduce your risk of side effects. These are generally considered the safest type of laxatives.

Lubricant laxatives work by coating the surface of the stools. This helps the stools hold in water so they move out of the body more easily. Glycerin suppositories lubricate the inside of the anus (the outside opening to the intestine) to make it easier to pass hard stools.

Stool softeners help mix fluid into stools to soften them. This makes stools easier to pass out of the body. An example is docusate (one brand name: Colace).

Saline laxatives draw fluid into the bowel from nearby tissue. This softens stools and helps the bowel move them out. Examples include polyethylene glycol (one brand name: Glycolax) or magnesium (called milk of magnesia).

Stimulant laxatives are the harshest type of laxatives. They cause the bowel to squeeze or contract to move the stools out. Stimulant laxatives should not be used more than a few days. When these laxatives are taken long term, the bowel can lose its tone and “forget” how to push the stool out on its own. Bisacodyl (one brand name: Dulcolax) is an example of a stimulant laxative.

Should I use a laxative to treat constipation?

Most of the time, constipation doesn’t require treatment with laxatives. It will usually go away on its own or if you make changes in your diet and other habits. For example, you can treat constipation by eating enough fiber, drinking enough fluids and getting enough exercise. Sometimes you may need a little help from an OTC medicine.

What are some common side effects of laxatives?

Most laxatives don’t have side effects if you use them correctly. However, sometimes they can cause cramping, gas, bloating, nausea or diarrhea.

Who shouldn’t take laxatives?

If you have a condition called phenylketonuria, you shouldn’t take a laxative that contains phenylalanine.

Don’t take laxatives if you have an allergy to any of the ingredients. Some people may be allergic to psyllium, a key ingredient in one type of bulk-forming laxative.

Laxatives aren’t meant for long-term use. Don’t use laxatives for longer than one week unless your doctor recommends it. Long-term use or overuse of laxatives can cause health problems. Overusing laxatives may also hide symptoms that are important for your doctor to know about. This could delay finding out about problems you have and also delay the treatment you need.

Could laxatives cause problems with any medicines or supplements I take?

Laxatives can get in the way of how your body absorbs certain medicines and some nutrients. In general, don’t take any other medicines within two hours of taking a laxative. If you’re taking a prescription medicine of any kind, talk to your doctor before taking a laxative. You also shouldn’t mix different types of laxatives, such as oral laxatives (which you take by mouth) and rectal laxatives (which you take by inserting a suppository or enema into your rectum, which is the last part of your large intestine). Don’t take bisacodyl within one hour of taking antacids or drinking milk.

Mineral oil and castor oil are sometimes used as laxatives, but they shouldn’t be used often. If mineral oil is used often, it can cause deficiencies of vitamins A, D, E and K. Castor oil, which is a stimulant laxative, can lead to chronic constipation because it can cause you to lose muscle tone in your bowel. Mineral oil and castor oil also interact with blood thinning medicines, antibiotics such as tetracycline, and certain heart and bone medicines.

When should I call my doctor?

If you have any of the following symptoms, talk to your doctor before using a laxative:

• Stomach pain
• Nausea
• Vomiting
• A sudden change in your bowel habits and it's been 2 weeks or longer
  

Stop taking laxatives and call your doctor if you have any bleeding from your rectum (the last part of the large intestine) or if you don’t have a bowel movement after using a laxative. These could be signs of a more serious problem.