Simply put, IBS alters how the intestines behave and work. To move food along the digestive tract, the muscles lining the intestines normally contract and relax intermittently. This pattern is thrown off with IBS, which leads to uncomfortable symptoms.² Pharmacists are essential in educating patients about how IBS works, food triggers, and ways to avoid IBS attacks. 

IBS is characterised by abdominal pain and discomfort with altered bowel habits that are not explained by any other mechanical, biochemical, or inflammatory cause with women being more likely to experience symptoms than men.³ Psychosocial variables, poor gastrointestinal motility, and visceral hypersensitivity all play a significant part in the pathophysiology of IBS; however, the specific cause is unclear. IBS has also been associated with psychological discomfort, such as worry and depression, which may be made worse by the patients' decreased quality of life because of their illness.¹ 

KINDS OF IBS 

“Because of the diverse presentations of diarrhoea and constipation in patients, IBS is categorised into several subtypes,” explained pharmacists Mark Schmick and Jaime Hornecker. “IBS with predominant constipation (IBS-C), IBS with predominant diarrhoea (IBS-D), and mixed or alternating IBS (IBS-A). The fourth subtype, postinfectious IBS, is associated with a GI infection and is uncommon.”³ 

SYMPTOMS 

The unclear picture of IBS symptomatology is worsened by the vague pathophysiology of the illness. IBS is typically assumed to be characterised by bloating, diarrhoea, constipation, and stomach cramps and discomfort. However, in some patients IBS may also involve psychological and physiological symptoms such exhaustion, a drop in libido, depression, anxiety, and increased everyday stress.³ 

Abdominal pain in IBS can manifest itself in several different ways. Patients report feeling a range of pain, from minor aches and pains to excruciatingly painful exacerbations. While defecation may be a pain-alleviating behaviour, stress and eating may worsen the pain.³ Hormones may also play a role with many women reporting more symptoms when they are menstruating.⁴ 

TRIGGERS  

Many patients identify food as a trigger for their IBS symptoms and food intolerances are common in IBS patients. Increasingly, rapidly fermentable, osmotically active, short-chain carbohydrates (including fructose, lactose, fructans and galactans, and sugar alcohols) have been recognised as an important trigger of IBS symptoms. Poorly absorbed carbohydrates can exert osmotic effects and lead to increased fermentation in the small bowel or colon, which can exacerbate symptoms in IBS patients who have underlying abnormalities in gut function and sensation. On the other hand, healthy patients with normal gut function and sensation rarely experience symptoms after a meal.⁵ 

MANAGEMENT  

Dietary modification: A study released by the South African Pharmaceutical Journal advised that patients can initially follow an approach of dietary exclusion whereby they would restrict certain foods that are known to exacerbate symptoms of IBS, and then gradually reintroduce them into their diet. Lead authors, Senior Lecturer Lorraine Thom, Community Service Pharmacist Pranusha Naicker, and Associate Professor Natalie Schellack recommended patients “eat regular meals, eat slowly, paced, and exclude certain foods. Even though the evidence is limited, fatty foods, caffeine, alcohol, carbonated drinks, gluten, and fermentable carbohydrates have been associated with patient discomfort. A diet rich in fibre can be beneficial to relieve constipation associated with IBS, though the patient could experience temporary increased flatus and abdominal distention”.⁶ 

Following the elimination of potential symptom triggers, the cornerstone of IBS management is pharmacotherapy: 

Fibre supplements: In a study on the management of IBS released by the American Gastroenterological Association, lead author Dr Michael Camilleri noted: “In patients with constipation-predominant IBS (IBS-C), fibre accelerates colonic or oroanal transit and this acceleration is associated with increased stool weight and percentage of unformed stools. As a group, patients with IBS-C do not consume less dietary fibre than control subjects. It is often postulated that fibre may decrease intracolonic pressure and thereby reduce pain because it is recognised that wall tension is one of the factors that contributes to visceral pain. Fibre reduces bile salt concentrations in the colon, and it has been speculated that this indirectly reduces colonic contractile activity.”⁶ 

Antidiarrheal agents: “Diarrhoea-predominant IBS (IBS-D) is associated with acceleration of small bowel and proximal colonic transit and responds to opioids,” Dr Camilleri explained in Management of the Irritable Bowel Syndrome published in the Gastroenterology Journal. “Most prefer to use loperamide over diphenoxylate, which contains atropine and may induce adverse effects that may be worrisome in elderly, e.g., bladder dysfunction, glaucoma, and tachycardia. Loperamide is a synthetic opioid that decreases intestinal transit, enhances intestinal water and ion absorption, and increases anal sphincter tone at rest. These physiologic actions seem to explain the improvement in diarrhoea, urgency, and faecal soiling observed in patients with IBS.”⁶ 

Antispasmodic agents: These drugs have been used for many years in the treatment of IBS. The goal of administering anticholinergic agents is to reduce postprandial abdominal pain, which is most likely brought on by colonic smooth muscle spasm. While anticholinergic medications like dicyclomine, hyoscine, and mebeverine can be used to provide short-term relief, their use may be limited by side effects such constipation, urine retention, dry mouth, and visual problems.¹ 

Probiotics: Bacteria and fungi that are naturally present in the body allowing it to function normally are called probiotics. Strains of bacteria known as Bifidobacterium and Lactobacillus and a strain of yeast called Saccharomyces boulardii are the most common probiotics found in supplements.⁷ These probiotics can be taken to relieve the symptoms of IBS experienced by patients. They are available as dietary supplements (capsules, tablets, and powders) or foods (yoghurt, fermented and unfermented milk, miso, tempeh, as well as certain juices and soy beverages).⁴ 

REFERENCES 

1. Thom, L.,et al. (2017). ‘Irritable Bowel Syndrome.’ Available from: http://www.sapj.co.za/index.php/SAPJ/article/view/2464/4724 
2. Hadley, S & Gaarder, S. (2005). ‘Treatment of Irritable Bowel Syndrome.’ Available from: https://www.aafp.org/pubs/afp/issues/2005/1215/p2501.html 
3. Chrohn’s and Colitis Foundation of America. ‘Inflammatory Bowel Disease and Irritable Bowel Syndrome: Similarities and Differences.’ Available from: https://www.crohnscolitisfoundation.org/sites/default/files/legacy/assets/pdfs/ibd-and-irritable-bowel.pdf 
4. Schmick, M & Hornecker, J. (2017). ‘Irritable Bowel Syndrome: A Review of Treatment Options.’ U.S Pharmacist. Available from: https://www.uspharmacist.com/article/irritable-bowel-syndrome-a-review-of-treatment-options 
5. Chey, W.,et al. (2015). ‘Irritable Bowel Syndrome: A Clinical Review.’ Available from: https://www.researchgate.net/publication/273155909_Irritable_Bowel_Syndrome_A_Clinical_Review 
6. Camilerri, M. (2001). ‘Management of the Irritable Bowel Syndrome.’ Available from: https://www.gastrojournal.org/article/S0016-5085(01)39115-1/pdf 
7. Pharmacy Times. (2018). ‘Pharmacists Play a Key Role in Counseling Patients About Probiotics.’ Available from: https://www.pharmacytimes.com/publications/issue/2018/September2018/pharmacists-play-a-key-role-in-counseling-patients-who-may-need-probiotics 
8. International Foundation for Gastrointestinal Disorders. (2016). ‘Probiotics and Antibiotics.’ Available from: https://www.aboutibs.org/medications/probiotics-and-antibiotics.html