Medications, such as nonsteroidal anti-inflammatory drugs (NSAIDs), opioids, and antidepressants, may cause constipation. Laxatives can help treat the effects of constipation these medications cause.

One of the most common digestive complaints people of all ages in the United States and other western countries experience is constipation. Every year, doctors get at least 2.5 million visits for constipation.

Some medicines taken orally can affect a person’s digestive system. This can make it hard for people to empty their bowels or pass hard, dry stools.

This article explores the medications that cause constipation, constipation’s potential causes, and the best laxatives that relieve medication-related constipation.

A variety of laxative medication in different colors.Share on Pinterest
Nathan Griffith/Getty Images

According to the National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK), constipation is when a person has fewer than three bowel movements weekly. Doctors characterize it by hard, dry, lumpy stools that can be difficult and even painful to pass. A person may also feel that they have not passed all of their stool even when they can have a bowel movement.

The following may also accompany constipation:

Learn more about constipation.

Too much straining due to constipation may also lead to complications, such as anal fissures, hemorrhoids, and rectal prolapse.

Anything that disrupts typical bowel function can cause constipation. Several medications may contribute to constipation:

Opioids or pain medications

Between 40–60% of people without cancer who take opioids get opioid-induced constipation. Doctors typically prescribe laxatives along with opioids to prevent constipation.

Opioids affect certain receptors in the gut wall, which slow down the peristaltic movement of the muscles that move food along the tract.

They may also suppress the secretion of water and electrolytes in the intestines and increase fluid absorption by the intestines, removing moisture from the stool.

Examples of opioids include:


Over-the-counter pain relievers, such as nonsteroidal anti-inflammatory drugs (NSAIDs) may cause gut problems.

Constipation is also a side effect of NSAIDs, such as ibuprofen (Advil) and naproxen (Aleve). Moreover, using them in higher doses may also lead to constipation.


Anticholinergics are a large drug class present in many over-the-counter (OTC) and prescription medications. These drugs prevent activity by the neurotransmitter acetylcholine, which enables muscles to move, and may cause constipation.

Examples of anticholinergics include:

Learn more about anticholinergic drugs.

Tricyclic antidepressants

Tricyclic antidepressants (TCAs) are a class of medications doctors prescribe to treat depression. These medications increase a person’s norepinephrine and serotonin levels by blocking acetylcholine. Some examples of TCAs include amitriptyline (Elavil) and desipramine (Norpramin).

One of the most common side effects of TCAs includes constipation.

Another class of antidepressants, serotonin specific reuptake inhibitors (SSRIs), can also cause constipation. Citalopram and fluoxetine are examples of SSRIs.


A person can take iron on its own or with multivitamins. Aside from causing darker-than-usual stools, it may also cause constipation.

Learn more about iron supplements.

There are different types of laxatives available on the market. Each can have different effects on a person’s body. The effectiveness of each type may also vary from person to person.

Below is a table comparing the different types of laxatives, including how they work and their potential side effects.

Type of laxativeGeneric and brand namesMode of actionSide effects
Stimulant laxativessenna (Senokot), bisacodyl (Dulcolax)Stimulates intestinal muscles to help stool move more quicklyBelching, diarrhea, cramping, nausea, changes in urine color
Osmotic laxatives (liquid, powder, suppository, saline)Polyethylene glycol or PEG (MiraLAX), lactulose, milk of magnesiaDraws water into the intestines to allow stool to pass easierBloating, cramping, gas, nausea, increased thirst, diarrhea
Emollient laxatives (stool softeners)docusate sodium (Colace)Makes stool softer by allowing fat and water to soften stoolElectrolyte imbalance if used too long
Bulk formersPsyllium (Metamucil), methylcellulose (Citrucel)Absorbs liquid in the intestines to form bulkier stools that are softer and easier to pass Gas, bloating, and cramping worsen constipation if not taken with enough fluids

Read more about stool softeners vs. laxatives here.

Doctors typically give stimulant laxatives for opioid-induced constipation. They may also ask a person to take osmotic laxatives daily.

Learn more about laxatives for constipation here.

For people with chronic constipation, a doctor may recommend a person take one of the following prescription drugs:

  • serotonin agonists, such as prucalopride (Motegrity)
  • secretagogues, such as linaclotide (Linzess)
  • osmotic agents
  • bile acid-modifying agents, such as elobixibat — currently only approved in Japan and Thailand

In people with opioid-induced constipation, doctors will likely suggest lifestyle changes and OTC medications. However, if these do not work, they will prescribe medications, which include:

A person experiencing constipation may want to manage their discomfort by stopping their medications or taking other medications. However, they should speak with a healthcare professional before taking action.

It is also important to note that the frequency of bowel movements varies from person to person. People may experience constipation if they pass stools less frequently than what is typical for them.

Before taking laxatives, making specific lifestyle changes may help. These include:

All types of laxatives can help a person with medication-induced constipation except for bulk-forming laxatives. These laxatives, such as psyllium, increase the bulk of the stool and distend the colon but do not help it pass.

They may make bowel movements very firm if a person does not take enough fluids, worsening their abdominal pain and contributing to a bowel obstruction.

Some osmotic medications contain magnesium and phosphate, such as magnesium citrate (Citroma) and milk of magnesia. The body partially absorbs these, which can harm people with kidney failure.

Some laxatives, such as bulk-forming laxatives, are gentle and generally safe to use long term. However, these will not help people with opioid-induced constipation.

Healthcare professionals do not typically prescribe other laxatives for long-term use. Ideally, a person should only use them occasionally, for up to 1 week. Overuse may lead to dependency and side effects.

It may be possible to improve constipation without taking laxatives. The following lifestyle and diet changes may help improve a person’s bowel movements:

Discover 13 home remedies for constipation here.

Here are some fiber-rich foods a person may add to their diet to relieve their constipation:

  • nuts, including peanuts and pecans
  • vegetables, such as carrots and broccoli
  • fruits, for example, unskinned apples and pears
  • legumes, such as kidney beans and chickpeas
  • whole grains, including oatmeal and whole wheat bread

OTC laxatives are generally safe and effective in treating constipation, including constipation caused by certain medications. However, it is best to speak with a doctor to check for any underlying causes. A person should always follow instructions and read the medication label for proper directions.

Overuse can cause the colon to stop responding to the usual dose and require larger doses to get the same effects, leading to dependence. Laxative abuse can also cause the intestines to lose nerve and muscle response, resulting in dependency.

A person should visit a healthcare professional if they notice any of the following:

  • constipation with severe abdominal pain
  • bloody stools
  • unintended weight loss
  • unexpected new onset of constipation

Suddenly developing long-standing constipation after having regular bowel movements is also a cause of concern.

There are several causes of constipation, including certain kinds of medications. The most common types include drugs for pain, allergies, hypertension, and overactive bladder.

Most of the time, lifestyle changes are enough to resolve constipation, but a person can also take OTC laxatives. People most commonly use stimulant laxatives to treat their medication-induced constipation.

A person experiencing constipation may ask a doctor or pharmacist if laxatives are suitable for them.