Medications for IBS Treatment

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There are many medications that can be used to treat irritable bowel syndrome (IBS). Different medications are used to treat a variety of IBS symptoms, including: 

  • Abdominal Pain
  • Constipation
  • Diarrhea
  • Bloating
  • Gas

There are a number of options for medicine and supplements for IBS. Some are over-the-counter (OTC) medications for IBS, while others need to be prescribed by your doctor.

Common medications include antidiarrheal, antispasmodics, laxatives, antidepressants, antiemetic drugs (to help with nausea), and pain relievers.

This page discusses a variety of medications as treatment options: 

  • Fiber Supplements
  • Laxatives for IBS-C or chronic constipation
  • Medications for IBS-D or chronic diarrhea
  • Pain Relievers
  • Gas Reducers

No single medication is effective for everyone, but they can provide relief from some symptoms. For more serious symptoms, you may need to see a physician who can prescribe medication if over the counter medications are failing.

Always talk to your healthcare provider about a treatment plan and which OTC or prescription medication might benefit you most. It’s important to also understand any side effects and risks with medications you are taking.

Fiber Supplements

Fiber helps keep the digestive system healthy. Fiber supplements bulk the stool and can help move stool through the bowel. 

Increasing fiber is often recommended as part of an overall diet change in order to improve digestion and reduce constipation.

Fiber is found naturally in foods, especially in high-fiber foods like beans, broccoli, avocados, whole grains, and other fruits and vegetables. 

It can sometimes be difficult to eat a lot of food for high fiber, so people find it easier to take fiber supplements. Fiber supplements come in different forms such as powders, pills, liquids, gels, bars, and even capsules.

There are no studies showing one form of fiber supplement works better than another.  They can be taken before or after meals or with other morning or evening medications.

There are several different fiber options on the market including:

Metamucil – Made up of psyllium husk, a natural fiber, that helps soften stools and increase water content. Metamucil for IBS comes in powders, capsules, and single serve packets. Click here to view online.

Fibercon – A natural fiber laxative containing calcium polycarbophil that is often used to treat constipation. Fibercon comes in the form of caplets. Click here to view online.

Benefiber – Benefiber is a plant-based prebiotic fiber supplement that comes in the form of powder, single serve packets, and chewables. Click here to view online.

Citrucel – Composed of methylcellulose fiber that helps relieve constipation.  It comes in powder and caplet form. Click here to view online.

If too much fiber is taken to start with, bloating and gas are common side effects. It’s recommended to slowly increase dosage to help reduce side effects.

Laxatives for IBS-C or Chronic Constipation

IBS with constipation (ISB-C) and chronic constipation can cause abdominal discomfort and pain, often relieved with defecation. Laxatives will help with increasing frequency of bowel movements and softening the stool to reduce straining. 

Laxatives work by softening hard feces by adding fluid to the stool. This makes the stool softer and easier to pass. The goal is to reduce constipation, pain or discomfort, and bloating without causing diarrhea.

The main options to relieve constipation symptoms include:

  • Osmotic laxatives
  • Stimulant laxatives
  • Prescription laxatives
  • Medications for opioid induced constipation
  • Suppositories
  • Enemas

Osmotic Laxatives

Osmotic laxatives are medications that add fluids to your colon through osmosis. The excess water in the intestine helps to soften the stool and move it through your body quicker.

  • MiraLAX (Polyethylene Glycol) – MiraLAX is often used for a longer duration but check with your doctor first. It comes in powder form, which is mixed into a liquid of your choice. Click here to view online
  • Milk of Magnesia – Good for occasional constipation. This comes in liquid form. Click here to view online.
  • Magnesium Citrate – Used for occasional constipation. This usually comes in softgel or capsule form. Click here to view online. 

Caution should also be used with magnesium containing laxatives if you have chronic kidney disease. Check with your doctor if you are using these regularly.  Be careful with long term use of osmotic laxatives as they can lead to electrolyte abnormalities.

Stimulant Laxatives – OTC

A stimulant laxative is a medicine that stimulates the bowel to move more quickly. It can be used for constipation.

These types of laxatives can relieve constipation quickly. They can also be used as rescue medicine if you haven’t had a bowel movement in a few days. 

Common side effects are cramping and abdominal pain. They may cause dependency issues.

Prescription Laxatives

A prescription laxative is a medication that is prescribed by your doctor to help with chronic constipation or IBS-C. 

If the above over-the-counter medications aren’t helping with your constipation, ask your doctor about prescription laxatives. 

There are a number of prescription drugs that your doctor can prescribe: 

  • Lactulose
  • Linaclotide (Linzess)
  • Lubiprostone (Amitiza)
  • Plecanatide (Trulance)
  • Tegaserod (Zelnorm) 
  • Prucalopride (Motegrity)

The main side effect of these laxative medications is diarrhea. In some patients, the diarrhea will slow down within a week or 2 of starting the medication.

Zelnorm should only be used in women under age 65 with no cardiovascular risk factors, including prior transient ischemic attack or stroke, heart attack, or angina. Ischemic colitis, a loss of blood flow to the colon resulting in abdominal pain and bloody diarrhea, can develop.

Opioid Induced Constipation

Opioids work by binding with receptors in your brain, but they can also bind with receptors in your gut or intestine, leading to constipation as a common side effect.

Opioid-induced constipation (OIC)  is characterized by decreased bowel frequency, formed, dry or hard stool consistency, and abdominal pain. It may be mild or severe, and it may occur during initiation of opioid therapy or after prolonged use.

Treatment options include increasing fluid intake, laxatives, and/or enemas. There are also prescription drugs specifically designed for the treatment of opioid induced constipation, including:

  • Naloxegol (Movantik)
  • Methylnaltrexone (Relistor)


Suppositories are a type of medication that is inserted into the rectum to treat certain medical conditions. They are used to treat constipation.  There are other types of suppositories which can be used for treatment of hemorrhoids.

Holding the suppository in for 15-20 minutes should give you the urge to defecate.

Read more about What is a Suppository?


An enema is a medical procedure in which fluid is introduced into the rectum to clean out the bowels and remove waste. This is typically only used in cases of severe constipation or before other medical procedures, like a colonoscopy or flexible sigmoidoscopy.

There are different liquids that can be used in cleaning the colon: 

  • Tap water enema
  • Saline enema
  • Soap suds enema
  • Sodium phosphate enema

Enemas containing foods like coffee or garlic are not recommended and may cause rectal trauma that can result in pain or bleeding.

Medications for IBS-D or Chronic Diarrhea

IBS with Diarrhea (IBS-D) and chronic diarrhea are usually treated with antidiarrheals. These medicines reduce the amount of watery stools produced.

These are common OTC and prescription drugs that are often used with bouts of diarrhea.  

Loperamide (Imodium) – Imodium slows down bowel motility, giving your body more time to reabsorb fluid from the stool.

Imodium can cause constipation if taken too often. However, it may not alleviate belly pain. Click here to view online.

Rifaxamin (Xifaxan) – Xifaxan is a gut selective antibiotic, which helps knock out the unhealthy gut flora to allow normal populations to get re-established. Normal dosage is 3 times a day for 2 weeks.

Side effects include nausea, swelling, and dizziness. If symptoms improve but recur, re-treatment is possible. Click here to view online.

Eluxadoline (Viberzi) – Viberzi is a prescription medication that slows bowel motility to reduce bowel frequency. It may also help with abdominal pain.

Do note that it should not be used in patients with pancreatic or liver disease, or in those who drink alcohol regularly or have had their gallbladder removed. Click here to view online.

Alosetron (Lotronex) – Lotronex is a prescription medication approved for women with severe symptoms from IBS-D that has not responded to other treatments. It slows bowel motility to reduce frequent stools.

Medication risks include it being associated with severe constipation or ischemic colitis, a loss of blood flow to the bowels which can cause worsening pain and bloody diarrhea. Click here to view online.

Pain Relievers

Antispasmodics – Hyoscyamine (Levsin) and dicyclomine (Bentyl) are prescription medications that help reduce abdominal spasms and cramping. They work by reducing muscle spasms or contractions of the bowel.

They are sometimes helpful in relieving the stomach pain and cramps associated with IBS, but have not been proven to be effective for IBS. Both come in an oral formulation as a tablet or capsule. Hyoscyamine can also be administered under the tongue.

Common side effects include dry mouth, blurred vision, headaches and drowsiness.

Tricyclic Antidepressants – Since IBS is thought to be a disorder of brain-gut interaction, antidepressants can be used to help modulate pain related to IBS. Antidepressants are prescription drugs that are used to affect neurotransmitters in the brain.

Antidepressants are commonly used to treat anxiety or depression, but they can also be used in patients with no known psychiatric diagnosis. These medications may take several weeks before an improvement is seen.

The most common side effects are sedation, dry mouth, and constipation. Some people can also develop urinary retention.  

SSRIs – These are another class of antidepressant medications that can be used for IBS symptoms, but more commonly cause diarrhea as a side effect.

Gas Reducers

Gas production and bloating are common IBS symptoms that many sufferers find difficult to control. Gas can cause discomfort and distension throughout the abdomen.

Gas reduction medicines will offer symptom relief. There are two main types of gas reducers: 

Simethicone (Gas-Ex or Phazyme) – Simethicone medications help to break up gas bubbles and can reduce bloating and gas pains. Gas-Ex and Phazyme are two common OTC brands available. Click here for Gas-Ex and here for Phazyme.

Beano – Beano is a digestive enzyme which can help break down hard to digest foods like beans and cruciferous vegetables, and reduce production of intestinal gas. Click here to view it online.

  • UCLA Medical School: Mind/Body Psychological Treatments for Irritable Bowel Syndrome
  • University of Washing School of Medicine: Complementary and alternative medicine for IBS in adults
  • University of Gothenburg, Sweden: Meditation over medication for irritable bowel syndrome?
  • Johns Hopkins University School of Medicine: Psychologic considerations in the irritable bowel syndrome
  • American College of Gastroenterology: Irritable Bowel Syndrome
  • NIDDK: Treatment for Irritable Bowel Syndrome

Written and Medically Reviewed By

  • Kelly Chow

    Kelly first experienced IBS symptoms at the age of 24 with major-to-severe symptoms. She underwent all types of tests and experimented with many treatments before finally finding ways to manage her symptoms. Kelly has written and shared ebooks and Gluten-Free diet plans that she has used to live life like she did before IBS.

  • Julie Guider, M.D.

    Dr. Julie Guider earned her medical degree from Louisiana State University School of Medicine. She completed residency in internal medicine at the University of Virginia. She completed her general gastroenterology and advanced endoscopy fellowships at University of Texas-Houston. She is a member of several national GI societies including the AGA, ACG, and ASGE as well as state and local medical societies.