Laxatives for Constipation: Types and Safe Use

If you are experiencing constipation, you may have tried lifestyle changes, such as eating more fiber and increasing your fluids. However, if these fail to provide relief, you may be considering laxative options.

There are various types of laxatives, and they work in different ways. For example, some soften the stool, while others help the lower intestines eliminate stool.

The four main types of laxatives found over the counter (without a prescription) are:

• Bulk-forming laxatives
• Osmotic laxatives
• Stimulant laxatives
• Stool-softening laxatives

Bulk-Forming Laxatives

Bulk-forming laxatives add fiber to the stool, helping the stool absorb more water. This leads to stools that are larger, softer, and easier to pass.

Bulk-forming laxatives are considered the safest type of laxative. Examples of bulk-forming laxatives are Metamucil, FiberCon, and Citrucel.

Experts recommend starting with a lower dose and slowly increasing as needed until you get the desired results. Drink plenty of fluids while taking a bulk-forming laxative.

When used for occasional constipation, products like Metamucil can take anywhere from 12 hours to three days to work. While your body adjusts to the fiber, you may experience some mild side effects such as bloating or changes in bowel habits.

Osmotic Laxatives

Osmotic laxatives work by increasing the amount of fluid in the intestines, which helps soften bowels and encourages stool to move through the colon faster. They may help you go more often and make it easier to go to the bathroom.

However, sometimes they may not help symptoms like pain and bloating, and may even worsen these symptoms. Experts recommend starting with a lower dose, and slowly increasing as needed until you see desired results. MiraLax (polyethylene glycol 3350) is a commonly used osmotic laxative.

MiraLax may take two to four days to result in bowel movement. Common side effects of MiraLax include nausea, bloating, cramping, and gas.

Stimulant Laxatives

Stimulant laxatives stimulate the walls of the large intestine, causing them to contract, and produce bowel movements. Examples of stimulant laxatives include Senokot (senna) and Dulcolax (bisacodyl).

Stimulant laxatives that are taken by mouth generally work within six to eight hours. Some stimulant laxatives are available as suppositories, which are inserted directly into the rectum. These work faster, in as little as 15 to 60 minutes.

Stimulant laxatives are generally recommended for use only for short periods of time. Taking them for longer can affect the bowel’s function, which can actually worsen constipation.

Stool Softeners

Stool softeners help bring fluid into the stools, making them softer and easier to pass. Colace (docusate) is a commonly used stool softener. Stool softeners are sometimes used after birth or after surgery.

Side effects may include nausea and stomach discomfort or cramping. Stool softeners generally take one to three days to start working.

Which Laxatives Do Experts Recommend?

There is little clinical data on treating occasional constipation—most data focus on people with ongoing constipation.

An international team of experts, however, offers some general recommendations for treating occasional constipation:

• Stimulant laxatives like MiraLax should be considered a first choice in treating occasional constipation.
• Stimulants may be more appropriate for people with constipation lasting one or two days, as opposed to MiraLax, which is more appropriate for longer-term constipation.
• They also suggest magnesium if these treatments do not work.

Other Types of Laxatives

In addition to the four types of laxatives outlined above, there are several other kinds of laxatives. Other OTC laxatives include:

• Saline laxatives, such as milk of magnesia, absorb water into the colon, helping to pass stool more easily. Results are often seen in 30 minutes to 6 hours. Side effects include loose, watery, or frequent stools.
• Lubricant laxatives, such as glycerin or mineral oil, make the stool slippery, helping it move more easily through the intestines. A mineral oil enema is inserted rectally, and can produce a bowel movement in two to 15 minutes. There is also a mineral oil liquid that is taken by mouth, and this type of mineral oil produces a bowel movement in six to eight hours. A glycerin suppository is inserted rectally and takes about 15 to 60 minutes to work.

There are also prescription laxatives, which may be used in people with various types of chronic constipation, such as the following examples of medications, which are taken by mouth:

• Linzess (linaclotide) is used in adults to treat irritable bowel syndrome with constipation (IBS-C) or chronic idiopathic constipation (CIC; constipation without a known cause and lasting at least three months). It can also be used to treat CIC in children age 6 to 17. Common side effects include diarrhea, stomach pain, gas, and bloating.
• Amitiza (lubiprostone) can be used to treat IBS-C in women 18 years and older. It can also be used to treat CIC in adults or opioid-induced constipation (OIC) in certain adults. Common side effects include nausea, diarrhea, stomach pain, bloating, gas, and headache.
• Trulance (plecanatide) can be used to treat CIC or IBS-C in adults. The most common side effect is diarrhea.
• Motegrity (prucalopride) treats CIC in adults. Common side effects are headache, stomach pain, nausea, vomiting, diarrhea, bloating, dizziness, gas, and tiredness.
• Movantik (naloxegol) can treat OIC in certain adults. Nausea, vomiting, diarrhea, gas, stomach pain, and headache are common side effects.

Do Laxatives Cause Side Effects?

Like any medication, laxatives can cause side effects. While different laxatives have different side effect profiles, some general side effects associated with laxatives are:

• Stomach cramping
• Gas
• Bloating
• Nausea
• Diarrhea

Serious side effects can occur in some cases, including in people who misuse or overuse laxatives. For example, some people fall into a pattern of taking laxatives at higher than recommended doses or for longer periods than recommended and then become dependent on laxatives. Others use laxatives to try to lose weight, but laxatives do not help people lose weight.

Serious side effects that may occur include:

• Constipation. Laxative overuse can actually cause constipation instead of relieving it. This is due to the intestines losing muscle and nerve response, then becoming dilated, and having trouble moving stool out. As a result, people need to take higher and higher doses to have a bowel movement.
• Alternating constipation, diarrhea, and gas. Along with the side effect of constipation, gas may become trapped in the intestines, also causing people to take more laxatives, starting a cycle of laxative use and constipation.
• Dehydration. Taking too many laxatives can cause people to lose too much fluid. Common dehydration symptoms include increased thirst, urinating less, headaches, dizziness, dry mouth, weakness, and less sweating.
• Electrolyte imbalances (higher or lower levels of minerals in the body such as sodium, calcium, and potassium) can cause symptoms like nausea, vomiting, headache, confusion, tiredness, and muscle weakness or spasms. 
• Blood in the stool. The colon can become irritated, causing blood in the stools. This can even lead to anemia (lack of healthy red blood cells).
• Impaired intestinal function. Long-term laxative abuse can affect the intestines to the point at which they can no longer contract to eliminate stool.
• Rectal prolapse. When laxative abuse causes ongoing severe diarrhea, the inside of the intestines can stick out through the opening of the anus, often requiring surgery to fix.

Tips for Taking Laxatives Safely

Here are some tips to take laxatives safely:

• Before taking the medication, check with your healthcare provider to make sure the laxative is safe with your medical conditions as well as the other medications you may take.
• Read the directions on the drug facts label and make sure you understand how to take the medication.
• Take the medication exactly as directed. Do not take more medication or take it more often than it states on the label.
• Keep track of your stools, and if you go more than three days without a bowel movement, contact your healthcare provider for medical advice.
• Taking laxatives occasionally as needed, or regularly for a few days at a time, is generally safe. However, if you find yourself needing to use a laxative for more than a week, it’s important to consult your healthcare provider. There could be an underlying condition causing the constipation that needs to be identified.

Other Ways to Treat Constipation

Sometimes, constipation may be related to another medical problem. Constipation may last for a short time or a long time. Many things can contribute to or cause constipation, including:

To treat or prevent constipation, it’s important to address the underlying reason.

You can make certain lifestyle changes that can help, including:

• Drink plenty of fluids, at least 8 cups per day, to stay hydrated and help prevent constipation.
• Gradually increase the amount of fiber in your diet with foods like bran, fruits, vegetables, nuts, and seeds.
• Eat meals on a regular basis, such as three meals a day with snacks in between. This helps your intestines function properly.
• Exercise regularly, which helps promote normal intestinal function. Consult your healthcare provider before beginning any new exercise program.
• About 30 minutes after eating, take time to sit on the toilet, allowing the normal urge for a bowel movement to kick in.
• Keep track of your bowel movements and notify your healthcare provider if you go more than three or four days without a bowel movement.

Summary

Before taking a laxative, it’s important to try lifestyle changes such as increasing fiber intake, drinking more water, and exercising regularly. There are various types of laxatives that can effectively treat constipation. Each type works differently and each should be used cautiously.

Follow directions to avoid potential side effects like dehydration or dependence. Consult your healthcare provider before using laxatives for more than a week for personalized advice on managing constipation and identifying any possible underlying health conditions.