There is no one-size-fits-all best medication for constipation. It depends on factors such as a person’s age and any health conditions they have. Several laxative medications are available over-the-counter (OTC) or through prescription.

However, for chronic constipation, doctors first recommend lifestyle practices of increasing fluid and fiber intake, as well as getting regular exercise.

When lifestyle practices do not lead to regular bowel movements, several classes of medications may help. They promote bowel movements through various actions, such as increasing water in the bowel or stimulating muscle contractions that speed transit time.

Constipation is common in the United States. It affects 16 in 100 adults of all ages and 33 in 100 adults aged 60 and older.

This article reviews some of the best medications for constipation in older adults, toddlers, and pregnant people. It also examines the types and side effects of OTC and prescription drugs for constipation.

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There are several types of OTC medications for constipation that work in different ways. These include the following:

Fiber supplements

An older 2015 study reports that fiber supplements promote bowel movements through two actions. They provide mechanical stimulation of the gut — resulting in softer, larger stools — and faster stool transit through the large intestine.

Certain types also increase the water content of stools, making them bulkier, softer, and easier to pass. Examples include:

Osmotic agents

Osmotic agents draw water into the bowel, which softens the stool and increases the number of bowel movements.

Examples include polyethylene glycol (Miralax) and a saline/salt solution, such as one with magnesium hydroxide (Milk of Magnesia).

Some risks are associated with specific types of osmotic agents. Those containing magnesium can cause metabolic disturbances, especially if a person has kidney disease. Doctors do not recommend any osmotic agent in someone with kidney or heart conditions.

Lubricants

Lubricants coat the stool and colon with a waterproof film. This allows it to stay soft and move through the intestine without losing moisture. An example is mineral oil (Fleet).

There are some risks associated with mineral oil use. They may cause liquid pneumonia and aspiration, which refers to inhaling objects down the windpipe and into the lungs. This can cause symptoms of coughing, difficulty breathing, and even choking.

Stimulants

Stimulants increase muscle contractions in the digestive tract, which speeds transit time. A person should only use this type of medication if other laxatives have not produced adequate results and their constipation is severe.

Examples include bisacodyl (Dulcolax), castor oil, and senna (Senokot).

Using stimulants for constipation also comes with risks. People may experience abdominal pain, and long-term use may cause damage to the intestinal muscles.

Doctors may prescribe one of the below medications:

Lubiprostone

Lubiprostone (Amitiza) can increase the amount of fluid in the bowels and allow stools to pass through more easily. It boosts bowel movement frequency, softens stools, and decreases pain in the abdomen. Doctors may recommend this medication to people with:

Side effects of lubiprostone can include:

Linaclotide or plecanatide

Linaclotide (Linzess) and plecanatide (Trulance) increase the secretion of fluid in the bowels, which can facilitate the passage of stools through the digestive tract. These drugs promote regular bowel movements in people with constipation that is not associated with a known cause, such as IBS.

However, in some cases, linaclotide can cause diarrhea.

Prucalopride

Prucalopride (Motegrity) can increase the movement of waste through the bowels. Doctors can use it to treat chronic idiopathic constipation.

This medication may cause side effects, such as:

A 2021 review examined 23 clinical trials to determine the types of laxatives that are safe and effective for people over the age of 65 years. The results found the following were reasonably safe to use for 3 months:

  • osmotic laxative
  • bulk laxatives — these contain fiber and increase the weight and water-retaining properties of the stool
  • stimulant laxative with or without fiber

Of these, the osmotic agent polyethylene glycol was effective and safe to use for about 6 months.

There are some side effects associated with using bulk-forming laxatives. These include:

Additionally, the regular use of laxatives — except for stool softeners and bulk-forming agents — can lead to:

  • dependence or serious motility, or movement, problems in the bowel
  • pancreatitis
  • IBS

Learn more about the differences between stool softeners and laxatives here.

Around 40% of pregnant people can experience constipation during pregnancy. In the first instance, they should try the following:

When this is not effective, doctors may consider laxative use. As most laxatives do not absorb into the general system, doctors do not expect short-term use to link to a higher risk of fetal abnormalities.

However, the risk of abnormalities is not the only issue to consider. Further research into the effectiveness of treating constipation in pregnancy is essential.

Pregnant people should consult their doctor before trying any medications when certain lifestyle changes have not helped relieve constipation.

Doctors first recommend lifestyle modifications for treating constipation in children. These may include drinking more fluids and eating more foods with fiber — up to a maximum of 35 g per day.

When further intervention is necessary, doctors may recommend an OTC laxative or enema, which involves inserting liquid or gas into the rectum to empty the bowels. Additionally, they may advise discontinuing any medications with side effects that can cause constipation.

Other treatments for constipation include:

  • Educating children on appropriate toilet behavior. For example, encouraging them to sit on the toilet after meals.
  • Disimpaction, which involves removing the buildup of stool with agents such as polyethylene glycol.
  • Maintenance laxatives.

Caregivers should seek advice from a doctor before starting children on laxatives and other medications to determine if they are safe and decide on an appropriate dose.

The Canadian Society of Intestinal Research cautions that it is important to only use laxatives in moderation and under the supervision of a doctor. If an individual experiences constipation more frequently than once per week, they should talk with a doctor before trying an OTC laxative.

Additionally, certain medications can cause constipation. In such cases, a doctor may reduce the dose or suggest an alternative. A doctor can also counsel someone who is dependent on laxatives on how to slowly stop their use.

Some medications to relieve constipation can cause serious side effects, such as hives, swelling, rashes, and difficulty breathing. People should seek urgent medical attention if they experience breathing difficulties.

The best medication for constipation depends on the person. Some research suggests it may be a fiber supplement for pregnant people and polyethylene glycol for older adults and children.

All laxatives have side effects, so it is best for someone who has constipation more often than once per week to talk with a doctor.

In addition, since the regular use of laxatives can cause dependence and other serious issues, doctors encourage individuals to engage in lifestyle practices that promote regularity. These include increasing fluid and fiber intake and exercising regularly.