Constipation is a common condition that makes it difficult to have a bowel movement. It can be caused by:
- Your diet
- Certain medications
- Dehydration
- Very little physical activity
- Intestinal problems
Constipation can usually be treated with medications called laxatives. Many laxatives are sold over the counter, meaning they can be purchased at the store without a prescription. Some are called stool softeners or fiber supplements.
Path to better health
How do laxatives work?
There are several different types of laxatives. Each of them works in a different way. These are the most common types.
Bulk-forming laxatives
These laxatives add “soluble” fiber to the stool, which causes it to absorb more water and produces larger, softer stools. Larger stools help the intestine contract and push the stool out. Bulk-forming laxatives are generally the safest type of laxative.
Some examples of bulk-forming laxatives include:
- Psyllium (1 brand name: Metamucil)
- Polycarbophil (1 brand name: FiberCon)
- Methylcellulose (1 brand name: Citrucel)
To reduce the risk of side effects, you should start slowly. Make sure to drink plenty of fluids while taking bulk-forming laxatives. Gradually increase the amount you use until you get the results you want.
Lubricating laxatives
These coat the surface of stool to make it slippery. This helps stool pass out of the body more easily. Glycerin suppositories lubricate the inside of the anus (the outer opening of the intestine). This makes it easier to pass hard stool out of the body.
Stool softeners
These help mix liquid with the stool to soften it, making it easier to remove from the body. An example of a stool softener is docusate (1 brand name: Colace).
Osmotic laxatives
These cause the intestine to retain more fluid, which softens the stool and helps the intestine to expel it. Examples include polyethylene glycol (one brand name: Miralax) and magnesium hydroxide solution (brand name: Milk of Magnesia).
Stimulant laxatives
These are the strongest types of laxatives. They cause the bowel to tighten or contract to push stool out. Bisacodyl (one brand name: Dulcolax) and sennosides (one brand name: Senokot) are examples of stimulant laxatives. Stimulant laxatives should not be used for more than a few days. When these laxatives are taken for a long time, the bowel may lose its muscle tone. It may “forget” how to push stool out on its own.
Should I use a laxative to treat constipation?
Most of the time, constipation does not require treatment with laxatives. It usually goes away on its own. You can also make changes to your diet and other habits. You can prevent or treat constipation by:
- Eat foods rich in soluble and insoluble fiber (bran, oats, foods made with whole grains, fruits and vegetables)
- Drink enough fluids (especially water)
- Get enough exercise
You can try all of these things and still suffer from constipation. In those cases, taking a laxative may help.
How to take over-the-counter laxatives safely?
Before taking an over-the-counter laxative, read the directions on the drug facts label. It will tell you how much medicine to take and how often to take it. If you have questions about how much medicine to take, call your family doctor or pharmacist. Keep track of the over-the-counter medicines you are using and when you take them. If you need to see a doctor, take this list with you.
Follow these tips to make sure you’re taking the right amount of an over-the-counter laxative:
- Take only the amount recommended on the medicine label. Do not assume that taking more medicine will work better or faster. Taking more than the recommended amount can be dangerous.
- If you are taking a prescription medication, ask your doctor if you can also take an over-the-counter laxative.
How can I safely store over-the-counter laxatives?
Keep all medicines out of the reach and sight of small children. Store medicines in a cool, dry place. This will help prevent them from losing effectiveness before their expiration date. Do not store medicines in bathrooms or bathroom cabinets. They are often hot and humid.
Things to keep in mind
Most laxatives have no side effects when used correctly. However, they can sometimes cause cramps, gas, bloating, nausea, or diarrhea.
Laxatives are not intended for long-term use. Do not use laxatives for more than a week unless your doctor recommends it. Long-term or excessive use of laxatives can cause health problems. Overuse of laxatives can also hide symptoms that your doctor should know about. This could delay the discovery of other health problems and the start of treatment.
Some people are at risk for electrolyte imbalances when taking certain laxatives. These include children and people with diabetes or kidney disease. Electrolytes are substances in the body that help nerves, organs, and muscles function properly.
Taking laxatives can cause you to get rid of too many electrolytes. When this happens, you may have side effects such as nausea, vomiting, headache, confusion, fatigue, and muscle weakness or spasms. Electrolyte imbalance can be serious. Check with your child’s doctor before giving your child a laxative. If you have a chronic illness, be sure to talk to your doctor before taking a laxative.
Who should not take laxatives?
Don’t take laxatives if you are allergic to any of their ingredients. Some people may be allergic to psyllium, a key ingredient in one type of bulk-forming laxative.
If you have a condition called phenylketonuria, you should not take a laxative that contains phenylalanine.
Could laxatives cause problems with any medications or supplements I take?
Laxatives can interfere with the body’s absorption of certain medications and nutrients. Do not take any other medications within 2 hours of taking a laxative. If you are taking any prescription medications, check with your doctor before taking a laxative. You should also not mix different types of laxatives. This includes oral laxatives (taken by mouth) and suppositories. Do not take bisacodyl within 1 hour of taking antacids or milk.
Mineral oil and castor oil are sometimes used as laxatives, but they should not be used frequently. If mineral oil is used frequently, it can lead to deficiencies in vitamins A, D, E, and K. Castor oil is a stimulant laxative. Excessive use of castor oil can cause loss of muscle tone in the intestine, which can lead to long-term constipation. Mineral oil and castor oil also interact with some medications, such as blood thinners, antibiotics such as tetracycline, and certain heart and bone medications.
When should I call my doctor?
If you have any of the following symptoms, talk to your doctor before using an over-the-counter laxative:
- Nausea
- Stomachache
- Sudden change in your bowel habits that lasts 2 weeks or more
- Vomiting
- Blood in the stool
- Black or dark-colored stools
Stop taking laxatives and call your doctor if you have rectal bleeding. Also call your doctor if you do not have a bowel movement after using a laxative. These could be signs of a more serious problem.
Questions to ask your doctor
- What type of laxative is best for me?
- Am I taking any other medications that could interact with a laxative?
- Do I need a prescription laxative or can I buy it over the counter?
- How long should I take a laxative?
- Can I use a bulk-forming laxative every day?
- Is there any test you recommend before I start taking laxatives?
