The 5 Most Common IBS Drugs: What Are They And How Do They Work? (Part 2)
Understanding Drug Therapy For Irritable Bowel Syndrome
It’s fairly common to take drugs for IBS (irritable bowel syndrome). But, do you know how your IBS drugs actually work? Find out how your IBS drugs affect your gut in part two of this article series by Sophie Ash, BSc(Hons), DipION, NNCP, Nutritional Therapist and IBS Specialist at On Your Plate Inc.
The 5 Most Common IBS Drugs: A Reminder
If you haven’t already read part one in this article series, check it out here.
Essentially, in Part 1, we explained why drugs should only be used as a last resort in IBS management (Ozdener & Rivkin, 2017). It’s just too risky! In our professional opinion, it’s much better to focus on all possible natural management techniques before resorting to IBS drugs.
The five main categories of IBS drugs are:
- Antidiarrheals
- Antispasmodics
- Antidepressants
- Antibiotics
- 5-hydroxytryptophan 3 receptor antagonists
We’ve already learned how antidiarrheals and antispasmodics work in Part 1. Now, let’s explore the final three categories of IBS drugs!
3. Antidepressants
Antidepressants are primarily recognized as drugs used to treat depression, given their name.
However, the way that antidepressants work actually has an impact on gut functionality too.
Taking drugs for IBS management isn’t a long-term solution.
Neurotransmitters are chemical signals that allow your nerve cells to communicate with each other and the rest of your body. Your cells rely on these chemical signals to know how they should function. And, this includes the cells of your gut.
There are two neurotransmitters in particular that influence digestive function:
- norepinephrine (noradrenaline)
- serotonin
Antidepressants increase how much of these neurotransmitters hang around in between your cells. This has mood-altering effects, as well as pain reduction (Ozdener & Rivkin, 2017).
One of the main IBS symptoms is abdominal pain and cramping. So, now it makes sense that antidepressants can be useful IBS drugs!
The most common antidepressant used for IBS is desipramine (a.k.a. Norpramin or Pertofrane).
4. Antibiotics
One of the root causes of IBS is a bacterial infection. There are several types of bacteria that can be implicated in IBS:
- gram-positive bacteria
- gram-negative bacteria
- protozoal organisms
When too much of a certain type of bacteria start growing in your small and/or large bowel, IBS symptoms can occur. One example is small intestinal bacterial overgrowth (a.k.a. SIBO) (Ozdener & Rivkin, 2017).
Therefore, taking an antibiotic can be helpful in IBS management.
Some antibiotics only target one specific type of bacteria. However, others can kill off all three types. The latter are, therefore, more likely to be effective as IBS drugs.
Rifiximin (a.k.a. Xifaxan) is one of the most common antibacterial IBS drugs. This is because it’s active against all three types of bacteria and is generally well-tolerated (Ozdener & Rivkin, 2017).
Taking drugs isn’t a long-term solution for IBS management.
5. 5-Hydroxytryptophan 3 Receptor Antagonists
5-hydroxytryptophan (5-HT) is just a fancy way of saying serotonin: one of the neurotransmitters that we mentioned earlier.
Therefore, 5-HT3 receptor antagonists are essentially IBS drugs that work by acting against serotonin.
90% of your serotonin is inside your digestive tract (Moore et al., 2013). Specifically, most serotonin is found inside your enterochromaffin cells. These are the cells that sit next to the nerve endings in your gut.
Because of their location, enterochromaffin cells are extremely sensitive to pressure changes in your bowel.
How is this relevant to 5-HT3 receptor antagonists?
Well, by blocking the receptors that detect serotonin, your enterochromaffin cells become less sensitive to pressure changes. This can result in pain reduction and, thus, less severe IBS symptoms (Ozdener & Rivkin, 2017).
The most common 5-HT3 receptor antagonist IBS drug is Alosetron (a.k.a. Lotronex). Alosetron not only reduces pain; it can also be effective against discomfort, urgency, and diarrhea (Moore et al., 2013).
So, there you have it! The main five categories of IBS drugs and how they work. Always seek professional advice when taking any kind of drug for IBS to ensure optimum safety and effectiveness.
Sophie Ash, BSc (Hons), DipION, NNCP is a Nutritional Therapist in downtown Toronto. She has a background in nutrition, medicine, genetics, and research. Before emigrating to Canada and establishing On Your Plate Inc., Sophie worked in hospitals throughout the UK as a Dietitian.
