IBS Medications and Supplements

Irritable bowel syndrome (IBS) is a common disorder indicated by a number of uncomfortable symptoms that affect a patient’s quality of life. Treatment of this disorder revolves around management of symptoms. A wide array of medications and supplements are used for the management of IBS, and this article will help you learn more about them and their safety and efficacy.

Types of IBS

Before we start discussing medications and supplements for IBS, it’s important to learn one thing - not all cases of IBS are the same. In fact, we can classify IBS into different categories[1]such as:

  • IBS with constipation (IBS-C) - indicated by stomach pain and discomfort, lumpy or hard stool, bloating, and abnormally delayed or infrequent bowel movement
  • IBS with diarrhea (IBS-D) - characterized by symptoms such as discomfort and pain as well as a loose or watery stool, urgent need to empty your bowel, frequent bowel movements
  • IBS with alternating constipation and diarrhea (IBS-A) - as you can presume, this type of IBS is indicated by periods of constipation-like symptoms followed by periods of diarrhea

Each type of IBS has about an equal number of patients. Bear in mind that sometimes a patient can have one IBS type and then experience some other type over time, i.e., it’s possible to alternate between types.

Medications for IBS-D

IBS-D Medicines

Stress, imbalance of gut microbiota, certain foods, and many other factors can contribute to IBS-D. In many cases the underlying cause of this problem is unknown, but there’s a lot we can do to manage it. A better understanding of the mechanisms associated with IBS-D would help ensure further development of new drugs for successful management of this condition. Below, you can see the list of medications that are used to treat IBS-D:

  • Rifaximin (xifaxan) - an antibiotic formulated to fight bacterial infection only in the intestines. Rifaximin is not like other antibiotics due to the fact it passes through the stomach into the intestines without reaching the bloodstream. That is why this antibiotic doesn’t treat infections in other parts of the body. A growing body of evidence confirms that taking rifaximin for two weeks improves several symptoms of IBS-D such as loose or watery stools, bloating, abdominal pain[2], and others
  • Loperamide (Imodium/gastro-stop) - a synthetic anti-diarrheal medication that is primarily used to decrease the frequency of diarrhea. Besides IBS-D, this drug is also used to address gastroenteritis and short bowel syndrome. Loperamide works by slowing down the rhythm of digestion in order to give more time for the small intestines to absorb nutrients and fluid from food. A study which compared the efficacy of loperamide versus placebo for treatment of IBS-D found that subjects who took this medication experienced improvement in stool consistency, urgency, pain, and their overall subjective response was better compared to the placebo group[3]
  • Atropine (Lomotil) - an anti-diarrheal drug available in tablet and liquid form. It functions to slow down colonic motility to improve absorption of more liquid from the stool. As a result, the stool becomes firmer which alleviates diarrhea symptoms. The drug is designed for short-term use only
  • Eluxadoline (viberzi) - a prescription medication formulated to address problems associated with IBS-D such as diarrhea and abdominal pain. The drug works directly in the intestines in order to slow down the movement of food during digestion. In addition, Viberzi reduces sensitivity to stimulation from nerves. One study found that Eluxadoline reduced symptoms of IBS-D in both men and women with sustained efficacy for more than six months[4]
  • Alosetron (Lotronex) - belongs to the class of drugs called 5-HT3 receptor antagonists which are used for management of severe IBS-D. Similarly to other drugs for this disorder, Alosetron works by slowing bowel movements through the intestines. A growing body of evidence confirms that Alosetron is effective for management of symptoms associated with IBS-D in men and women[5]
  • Bismuth subsalicylate (Kaopectate, Pepto-Bismol) - a medication that treats loose stools and diarrhea. Mechanism of action is similar to the drugs mentioned above, it works by slowing down bowel movements, but it doesn’t relieve other symptoms of IBS-D
  • Calcium (supplement) - your body needs calcium to function properly, and while most of your calcium serves to strengthen teeth and bones, a certain portion participates in various bodily functions. These bodily functions include fluid secretion, muscle movement, nerve cell communication, and blood pressure. Due to these roles, calcium supplementation can be considered a viable management option for IBS-D
  • Antidepressants - bearing in mind that antidepressants work at the level of the spinal cord and brain they block pain messages between the brain and GI tract. This leads to an improved brain-gut relationship which then aids the management of symptoms associated with this condition. Different types of antidepressants are available, such as:
    • Tricyclic - amitriptyline (Elavil), Nortriptyline, imipramine - work to increase levels of norepinephrine and serotonin, two neurotransmitters as well as to block the action of other neurotransmitters in order to balance the concentration of these messengers in the brain for depression relief. Evidence shows this type of antidepressant can be effective in the management of diarrhea-predominant IBS[6]
    • SSRIs - citalopram, fluoxetine (Prozac), Paroxetine (Paxil), Sertraline (Zoloft) - selective serotonin reuptake inhibitors (SSRIs) reduce symptoms of moderate to severe depression and they work by increasing levels of serotonin in the body. These antidepressants are considered effective for treatment of IBS although the exact mechanism of action needs further research[7]
    • SNRI - duloxetine (Cymbalta), desvenlafaxine (Pristiq, Khedezla), levomilnacipran (Fetzima), venlafaxine (Effexor XR) - serotonin-norepinephrine reuptake inhibitors (SNRIs) treat depression as well as anxiety and other problems. They work by acting on chemical messengers or neurotransmitters to improve communication between brain cells. This is important if we bear in mind-brain function and gut health are connected with one another

Side Effects for IBS-D Medications

Every medication comes with a certain risk of side effects, but while some drugs have severe adverse reactions, others do not. Before you start taking some of the above-mentioned anti-diarrheal drugs, it’s important to learn more about their side effects and potential interactions with other medications. Some anti-diarrheal medications can cause problems with other drugs, such as:

  • Antibiotics - in some cases antibiotics can cause a severe intestinal condition (Clostridium difficile-associated diarrhea), and it occurs weeks after antibiotic treatment has stopped. Anti-diarrheal medications can make this condition worse which is why it is usually not recommended to take these drugs after recent antibiotic use
  • Prescription pain medicines - anti-diarrheal drugs decrease bowel movements so when used in combination with other anti-motility drugs they can cause constipation. Prescription pain medications including opioids belong to this category
  • Blood-thinning medicines - it is recommended that patients with blood circulation and blood clot problems consult their doctor before using anti-diarrheal medications
  • Gout medication - anti-diarrheal medications may affect uric acid levels and, thus, interact with gout drugs
  • Arthritis medication - anti-diarrheal drugs may interact with absorption of medications taken for arthritis
  • Diabetes medication - some anti-diarrheal medications may interact with anti-diabetes drug Tolbutamide
  • Antiviral medicines for HIV - loperamide decreases absorption of antiviral drugs such as Saquinavir (Invirase, Fortovase)

Medications for IBS-C

IBS-C Medicines

Management of irritable bowel syndrome with constipation requires a well-crafted strategy that involves lifestyle modifications and medications. Using one approach doesn’t work, most patients find relief when they combine multiple approaches. Medications used for IBS-C include:

  • Lubiprostone (amitiza) - belongs to the class of drugs known as chloride channel activators and it works by increasing the amount of fluid in the intestines to make the passage of stool easier. The medication is used for IBS-C as well as for chronic idiopathic constipation, and opioid-induced constipation. Studies show that the drug is both effective and well-tolerated for the relief of constipation and other symptoms linked with IBS-C[8]
  • Linaclotide (linzess) - works by enhancing secretion of chloride and water in the intestines to stimulate bowel movements and soften stools. It is used for IBS-C and chronic constipation with no known cause. Evidence confirm Linaclotide is an effective and well-tolerated treatment option for adults with IBS-C and it also works to alleviate other symptoms such as abdominal pain and discomfort[9]
  • Ispaghula husk (fybogel, ispagel) - a bulk-forming laxative used for constipation. Through its ability to increase the bulk of stool, the drug encourages bowels to move the stool through the digestive tract. This alleviates constipation and discomfort caused by it
  • Psyllium husk (equate, konsyl, Metamucil, reguloid, fiberall, perdiem) - a form of fiber made from the husks of the Plantago ovata seeds. It soaks up water in the gut to make bowel movements easier
  • Laxatives - substances that loosen stools and increase bowel movements. They are used to address constipation. We can divide them into the following categories:
    • Stimulant laxatives (Bisacodyl - Correctol, Dulcolax, Sennosides - ex-lax, Senokot), castor oil, the plant cascara) - work by stimulating digestive tract walls to speed up bowel movements. They have a more rapid mechanism of action compared to osmotic laxatives[10]
    • Osmotic laxatives (Lactulose) - work by softening the stool to make it easier to move through the bowel
  • Antidepressants - the same way these drugs help management of diarrhea, they can also improve symptoms linked with IBS-C.
    • Tricyclic - amitriptyline (Elavil), Nortriptyline, doxepin, desipramine - when used in lower doses, they can help patients with IBS-C although they demonstrate greater efficacy when taken for IBS-D
    • SSRIs - fluoxetine (Prozac), Paroxetine (Paxil), Sertraline (Zoloft) - evidence confirms SSRIs such as fluoxetine is a well-tolerated short-term treatment for pain and constipation-predominant IBS[11]

Medications for Abdominal Pain and Bloating

Medicines for Abdominal Pain and Bloating

A vast majority of patients with IBS experience abdominal pain, discomfort, and bloating. These symptoms prevent patients from focusing on their daily activities, but successful management is possible. Besides lifestyle adjustments, medications can also provide much-needed relief. These medications include:

  • Antispasmodics - medications used for muscle relaxation. They work to relieve cramps, pain, and discomfort. Antispasmodic drugs used for IBS are:
    • Bentyl (Dicyclomine) - relieves spasms in the gastrointestinal tract through smooth muscle relaxation. Not many studies have been conducted on this subject, but available evidence confirms Dicyclomine was more effective than placebo in improving the overall condition of the patient, decreasing abdominal pain, tenderness, and improving bowel habits[12]
    • Levsin (Hyoscyamine) - provides relief from muscle spasms including in your digestive tract
    • Peppermint oil - used for a wide array of purposes and it is considered one of the most beneficial natural approaches for IBS[13] relief. The underlying mechanisms are poorly elucidated, but it could be down to the relaxing effects of peppermint oil
  • Antidepressants - they balance neurotransmitters in the brain to improve connections between brain cells and also to repair the gut-brain relationship. Through their potential to improve relaxation and act on stress, anxiety, antidepressants can also calm your stomach and tackle pain. They work to reduce visceral hypersensitivity which is behind pain and discomfort. The impact of different types of antidepressants on abdominal pain and bloating is poorly understood, but it is generally believed that all three kinds can be helpful
    • Tricyclic - amitriptyline (Elavil), Nortriptyline, imipramine
    • SSRIs - citalopram, fluoxetine (Prozac), Paroxetine (Paxil), Sertraline (Zoloft), Escitalopram (Lexapro)
    • SNRIs - Venlafaxine (Effexor), Duloxetine (Cymbalta), Desvenlafaxine (Pristiq), Milnacipram (Savella)
  • Antibiotics - they slow down or destroy the growth of bacteria, and it’s important to mention antibiotics don’t treat viruses such as cold or flu.
  • Gut-specific antibiotics - rifaximin (xifaxan) is considered the best and most effective antibiotic for patients with IBS because it acts on the gut specifically. On the other hand, other antibiotics that are used don’t work specifically on your digestive system. Not only is rifaximin effective for treatment of diarrhea, but it is also considered safe with minimum side effects and drug interactions.


Although irritable bowel syndrome is an uncomfortable condition, there are many things patients can do to feel better. Throughout this post, you’ve had the opportunity to learn more about the medications used for this purpose. Prior to using these medications, consult your doctor.


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