Introduction
Irritable Bowel Syndrome (IBS) is a prevalent, chronic condition characterized by persistent abdominal discomfort or pain, often linked to bowel movements and changes in bowel habits. Individuals with IBS may experience a range of symptoms, including altered bowel function (constipation, diarrhea, or both), and abdominal bloating. These symptoms can sometimes overlap with other gastrointestinal conditions like non-ulcer dyspepsia or celiac disease, making diagnosis challenging. Patients often present in primary care settings with diverse symptoms, some of which they may hesitate to discuss openly without direct and sensitive questioning.
IBS manifests with varying symptom patterns, commonly categorized as diarrhea-predominant, constipation-predominant, or mixed. It frequently affects individuals between 20 and 30 years of age and is notably more common in women than men. Population prevalence estimates range from 10% to 20%, with recent data indicating a significant occurrence in older adults as well. Therefore, IBS should be considered in older patients presenting with unexplained abdominal symptoms.
This guideline focuses on several critical aspects of IBS management in primary care: establishing a definitive diagnosis, referring patients to specialist care only when ‘red flag’ symptoms suggestive of other serious conditions are present, providing comprehensive lifestyle and dietary advice, utilizing appropriate pharmacological and psychological interventions, and ensuring effective referral and follow-up strategies. It is important to note the relevance of NICE guidelines on suspected cancer recognition and referral when considering secondary care pathways for patients with potential red flag symptoms.
The primary objectives of this guideline are to:
- Define clear, positive diagnostic criteria for individuals presenting with symptoms indicative of IBS.
- Offer guidance on clinically effective and cost-effective management strategies for IBS within primary care settings.
- Establish clinical criteria for referral to specialist IBS services, considering cost-effectiveness.
Recommendations About Medicines
This guideline assumes that healthcare providers will utilize the Summary of Product Characteristics for each medication to inform their prescribing decisions in consultation with individual patients.
It is important to note that this guideline may recommend certain medications for uses outside of their UK marketing authorization at the time of publication, particularly when strong evidence supports such use. In these cases, prescribers should adhere to relevant professional guidelines and accept full responsibility for their decisions. Furthermore, obtaining and documenting informed consent from the patient (or their authorized representative) is crucial. For detailed information, refer to the General Medical Council’s Good practice in prescribing and managing medicines and devices guidelines. Medicines recommended for ‘off-label’ use are clearly indicated with a footnote in the recommendations.
Patient-Centered Care
This guideline provides best practice recommendations for the care of adult patients with IBS, emphasizing a patient-centered approach.
Patients and healthcare professionals share rights and responsibilities as outlined in the NHS Constitution for England. All NICE guidelines are developed to reflect these principles. Treatment and care plans should be tailored to individual patient needs and preferences. Patients should be empowered to make informed decisions about their healthcare in partnership with their healthcare providers. Healthcare professionals should follow the Department of Health’s guidelines on consent. For patients who lack the capacity to make decisions, healthcare professionals should follow the Mental Capacity Act code of practice and the supplementary code of practice on deprivation of liberty safeguards.
NICE has also published guidance on enhancing patient experience within adult NHS services, and all healthcare professionals should integrate the recommendations from the patient experience in adult NHS services guideline.
Key Priorities for Implementation
The following recommendations were identified as key priorities in the 2008 guideline and remain unchanged in the 2015 update, highlighting their continued importance for effective IBS management in primary care.
Initial Assessment
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Healthcare professionals should consider IBS assessment for individuals reporting any of the following symptoms for at least six months:
- Abdominal pain or discomfort
- Bloating
- Change in bowel habit. [2008]
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IBS diagnosis should only be considered if abdominal pain or discomfort is present that is either relieved by defecation or associated with altered bowel frequency or stool form. This should be accompanied by at least two of the following four symptoms:
- Altered stool passage (straining, urgency, incomplete evacuation)
- Abdominal bloating (more prevalent in women), distension, tension, or hardness
- Symptoms worsened by eating
- Passage of mucus.
Additional symptoms such as lethargy, nausea, backache, and bladder issues are common in IBS patients and can support the diagnosis. [2008]
Diagnostic Tests
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For patients meeting IBS diagnostic criteria, the following tests are essential to rule out other conditions:
- Full blood count (FBC)
- Erythrocyte sedimentation rate (ESR) or plasma viscosity
- C-reactive protein (CRP)
- Antibody testing for celiac disease (endomysial antibodies [EMA] or tissue transglutaminase [TTG]). [2008]
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The following tests are deemed unnecessary for confirming IBS diagnosis in patients who meet the clinical criteria:
- Ultrasound
- Rigid/flexible sigmoidoscopy
- Colonoscopy; barium enema
- Thyroid function test
- Fecal ova and parasite test
- Fecal occult blood
- Hydrogen breath test (for lactose intolerance and bacterial overgrowth). [2008]
Dietary and Lifestyle Advice
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Patients with IBS should receive comprehensive information emphasizing the crucial role of self-management in effectively controlling their symptoms. This should include guidance on general lifestyle adjustments, physical activity, dietary modifications, and symptom-targeted medications. [2008]
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Healthcare providers should review the fiber intake of IBS patients, typically adjusting it downwards while monitoring symptom response. Discouraging insoluble fiber (e.g., bran) is advised. If increased fiber intake is recommended, it should focus on soluble fiber sources such as ispaghula powder or foods rich in soluble fiber (e.g., oats). [2008]
Pharmacological Therapy
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Patients should be educated on how to adjust their laxative or antimotility agent dosages based on their clinical response. Dosage titration should aim to achieve a soft, well-formed stool, corresponding to type 4 on the Bristol Stool Form Scale. [2008]
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Tricyclic antidepressants (TCAs) should be considered as a second-line treatment option for IBS patients if laxatives, loperamide, or antispasmodics are ineffective. Initiate treatment at a low dose (5–10 mg amitriptyline equivalent) once nightly, with regular reviews and dose adjustments up to 30 mg if necessary. [1] [2015]
1. Recommendations
Diagnosing and managing Irritable Bowel Syndrome (IBS) in primary care can be challenging for both patients and clinicians. It is essential for both parties to acknowledge the limitations of current IBS knowledge and understand the chronic nature of this condition.
1.1. Diagnosis of IBS
Accurate diagnosis is fundamental to effective IBS management. The primary focus should be on establishing the patient’s symptom profile, with abdominal pain or discomfort as a key indicator. It is important to thoroughly assess the characteristics of the pain or discomfort, including its intensity, quality, location (which can vary throughout the abdomen), and variability. This helps differentiate IBS pain from cancer-related pain, which typically has a fixed location.
Utilizing the Bristol Stool Form Scale (Appendix I in the full guideline) can aid patients in describing their bowel habits, particularly stool quality and consistency. Patients with IBS often report incomplete evacuation or rectal hypersensitivity, as well as urgency, especially in diarrhea-predominant IBS. It’s important to note that approximately 20% of individuals with fecal incontinence only disclose this symptom when directly asked. Healthcare professionals should use open-ended questions to sensitively explore these symptoms, such as, ‘Can you describe how your symptoms impact your daily life, for example, leaving the house?’. Cultural, ethnic, and communication needs should be carefully considered, especially for patients for whom English is not their primary language or those with cognitive or behavioral challenges, to ensure effective and sensitive consultations.
1.1.1. Initial Assessment
1.1.1.1. Healthcare professionals should consider assessment for IBS if a patient reports experiencing any of the following symptoms for a duration of at least 6 months:
- Abdominal pain or discomfort
- Bloating
- Change in bowel habit. [2008]
1.1.1.2. All patients presenting with symptoms suggestive of IBS should undergo a comprehensive assessment and clinical examination to identify ‘red flag’ indicators. Referral to secondary care for further investigation is necessary if any of these red flags are present:
- Signs and symptoms of cancer, as detailed in NICE guidelines on recognition and referral for suspected cancer.
- Inflammatory markers indicative of inflammatory bowel disease. [2017]
1.1.1.3. This recommendation has been withdrawn [2017].
1.1.1.4. An IBS diagnosis should be considered only if the patient experiences recurrent abdominal pain or discomfort that is either relieved by defecation or associated with a change in bowel frequency or stool form. This should be accompanied by at least two of the following four additional symptoms:
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Altered stool passage (straining, urgency, or a sense of incomplete evacuation)
-
Abdominal bloating (more common in women), distension, tension, or hardness
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Symptoms exacerbated by eating
-
Passage of mucus.
Other common symptoms in IBS patients, such as lethargy, nausea, backache, and bladder symptoms, can support the diagnosis. [2008]
1.1.2. Diagnostic Tests
1.1.2.1. In patients who fulfill the IBS diagnostic criteria, the following tests are recommended to exclude other potential diagnoses:
- Full blood count (FBC)
- Erythrocyte sedimentation rate (ESR) or plasma viscosity
- C-reactive protein (CRP)
- Antibody testing for celiac disease (endomysial antibodies [EMA] or tissue transglutaminase [TTG]). [2008]
1.1.2.2. The following tests are not needed to confirm an IBS diagnosis in patients meeting the diagnostic criteria:
- Ultrasound
- Rigid or flexible sigmoidoscopy
- Colonoscopy or barium enema
- Thyroid function test
- Fecal ova and parasite test
- Fecal occult blood
- Hydrogen breath test (for lactose intolerance and bacterial overgrowth). [2008]
Image: Bristol Stool Form Scale chart, aiding in the description of stool types for IBS diagnosis and management.
1.2. Clinical Management of IBS
1.2.1. Dietary and Lifestyle Advice
1.2.1.1. Patients with IBS should receive comprehensive information emphasizing the importance of self-management in effectively managing their condition. This should include detailed advice on lifestyle modifications, physical activity, dietary adjustments, and the use of symptom-targeted medications. [2008]
1.2.1.2. Healthcare professionals should encourage IBS patients to prioritize and maximize their leisure time and incorporate relaxation techniques into their daily routines. [2008]
1.2.1.3. Assessing the physical activity levels of IBS patients is recommended, ideally using tools like the General Practice Physical Activity Questionnaire (GPPAQ; Appendix J in the full guideline). Patients with low activity levels should receive brief counseling and advice to promote increased physical activity. [2008]
1.2.1.4. A thorough assessment of diet and nutrition is crucial for IBS management. General dietary advice should include:
- Maintaining regular meal times and eating slowly and mindfully.
- Avoiding missed meals or long intervals between meals.
- Consuming at least 8 cups of fluids daily, primarily water or non-caffeinated beverages like herbal teas.
- Limiting tea and coffee intake to a maximum of 3 cups per day.
- Reducing alcohol and carbonated drink consumption.
- Potentially limiting high-fiber foods such as wholemeal products, high-fiber cereals, and whole grains.
- Reducing intake of ‘resistant starch’ found in processed and reheated foods.
- Limiting fresh fruit to 3 portions per day (approximately 80g per portion).
- Patients with diarrhea should avoid sorbitol, an artificial sweetener common in sugar-free products and some diabetic and slimming foods.
- For patients experiencing wind and bloating, incorporating oats (like oat-based cereals or porridge) and linseeds (up to 1 tablespoon daily) may be beneficial. [2008]
1.2.1.5. Healthcare providers should review the fiber intake of IBS patients, adjusting it (usually reducing) while closely monitoring symptom changes. Insoluble fiber (e.g., bran) should generally be discouraged. If increasing fiber intake is advised, soluble fiber sources such as ispaghula powder or oat-rich foods are preferred. [2008]
1.2.1.6. If IBS patients choose to use probiotics, they should be advised to use the product for at least 4 weeks while carefully monitoring its effects. Probiotics should be taken at the manufacturer’s recommended dosage. [2008]
1.2.1.7. Healthcare professionals should discourage the use of aloe vera for IBS treatment due to lack of evidence and potential harm. [2008]
1.2.1.8. If IBS symptoms persist despite adherence to general lifestyle and dietary advice, further dietary management strategies should be offered. This should include advice on single food avoidance and exclusion diets, such as a low FODMAP diet, and should only be provided by healthcare professionals with specialized expertise in dietary management. [new 2015]
Image: Illustration of various dietary fiber sources, highlighting the difference between soluble and insoluble fiber in IBS management.
1.2.2. Pharmacological Therapy
Pharmacological management decisions should be guided by the specific nature and severity of IBS symptoms. The following recommendations assume that medication choices, whether single or combined, are determined by the predominant symptom(s).
1.2.2.1. Healthcare professionals should consider prescribing antispasmodic agents for IBS patients to help manage abdominal pain and spasms. These should be used as needed, alongside dietary and lifestyle modifications. [2008]
1.2.2.2. Laxatives should be considered for treating constipation in IBS patients. However, lactulose is not recommended due to potential side effects and limited efficacy in IBS. [2008]
1.2.2.3. Linaclotide should be considered for IBS patients only under specific conditions:
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When optimal or maximally tolerated doses of various laxative classes have failed to provide relief.
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In patients who have experienced persistent constipation for at least 12 months.
Patients initiated on linaclotide should be followed up after 3 months to assess efficacy and tolerability. [new 2015]
1.2.2.4. Loperamide is recommended as the first-line antimotility agent for managing diarrhea in IBS. [2008]
1.2.2.5. Patients should be educated on self-adjusting doses of laxatives or antimotility agents based on their individual clinical response. The goal is to titrate the dose to achieve a soft, well-formed stool, ideally type 4 on the Bristol Stool Form Scale. [2008]
1.2.2.6. Tricyclic antidepressants (TCAs) should be considered as a second-line treatment for IBS if laxatives, loperamide, or antispasmodics have not been effective. Initiate treatment at a low dose (5–10 mg amitriptyline equivalent), administered once at night, with regular follow-ups and potential dose adjustments up to 30 mg. [2] [2015]
1.2.2.7. Selective serotonin reuptake inhibitors (SSRIs) should be considered for IBS patients only if TCAs are ineffective or not tolerated. [2] [2015]
1.2.2.8. When offering TCAs or SSRIs, it is crucial to discuss potential side effects with patients. For patients starting these medications at low doses for IBS pain or discomfort, a follow-up appointment after 4 weeks and then every 6–12 months is recommended to monitor effectiveness and side effects. [2] [2015]
1.2.3. Psychological Interventions
1.2.3.1. Referral for psychological interventions, such as cognitive behavioral therapy (CBT), hypnotherapy, and/or other forms of psychological therapy, should be considered for IBS patients who have not responded adequately to pharmacological treatments after 12 months and who continue to experience a persistent symptom profile, often described as refractory IBS. [2008]
1.2.4. Complementary and Alternative Medicine (CAM)
1.2.4.1. Acupuncture is not recommended for the treatment of IBS due to insufficient evidence of benefit. [2008]
1.2.4.2. Reflexology is also not recommended for IBS treatment due to a lack of proven effectiveness. [2008]
1.2.5. Follow-up
1.2.5.1. Follow-up plans should be collaboratively agreed upon between the healthcare professional and the patient, based on the individual’s symptom response to implemented interventions. Regular follow-up should be integrated into annual patient reviews. The emergence of any ‘red flag’ symptoms during management and follow-up should prompt further investigation and potential referral to secondary care. [2008]
More Information
Further details and related guidelines can be found in the NICE pathway on irritable bowel syndrome in adults: https://pathways.nice.org.uk/pathways/irritable-bowel-syndrome-in-adults.
For related NICE guidance, see the web page on digestive tract conditions: https://www.nice.org.uk/guidance/conditions-and-diseases/digestive-tract-conditions.
Detailed discussions by the guideline committee, evidence reviews, and information on guideline development are available in the full guideline: http://www.nice.org.uk/Guidance/CG61/evidence, including committee details and development processes: http://www.nice.org.uk/Guidance/CG61/documents.
2. Research Recommendations
In 2008, the Guideline Development Group proposed several research recommendations to enhance NICE guidance and patient care. The 2015 update included three additional research recommendations focusing on the clinical and cost-effectiveness of the low FODMAP diet, low-dose TCAs and SSRIs in primary care, and the efficacy of computerised CBT and mindfulness therapy. These can be found in the addendum: http://www.nice.org.uk/Guidance/CG61/Evidence.
2.1. Low-Dose Antidepressants
Is the use of low-dose TCAs, SSRIs, and serotonin-norepinephrine reuptake inhibitors (SNRIs) effective as a first-line treatment for IBS? Which option is the most effective and safest?
Why This Is Important
Current research has compared TCAs and SSRIs against placebo in IBS treatment, but studies specifically on low-dose efficacy are lacking. Clinicians on the Guideline Development Group suggest that low-dose TCAs (e.g., 5–10 mg amitriptyline equivalent) could be a preferred IBS treatment, yet robust evidence is needed. SNRIs also show potential for IBS-related pain management. A large-scale randomized trial comparing SSRIs, TCAs, and SNRIs against placebo is warranted. Participants should be adults with confirmed IBS, stratified by IBS type (diarrhea-predominant, constipation-predominant, or mixed), and randomized to treatment groups. The primary outcome should be the overall improvement in IBS symptoms, with secondary measures including health-related quality of life and adverse effect monitoring, assessed at 12, 26, and 52 weeks post-treatment initiation.
2.2. Psychological Interventions
Are CBT, hypnotherapy, and psychological therapy equally effective in managing IBS symptoms, either as first-line treatments in primary care or for refractory IBS?
Why This Is Important
Evidence supports the effectiveness of psychological interventions compared to control groups, particularly for refractory IBS, although many studies are small. CBT, hypnotherapy, and psychological therapy are considered helpful for coping with IBS symptoms, but the optimal timing and role (first-line vs. later-line therapy) are unclear. A large randomized trial comparing CBT, hypnotherapy, and psychological therapy (specifically psychodynamic interpersonal therapy) is proposed. Participants should be adults with IBS, stratified by refractory status, and randomized to treatments. The primary outcome should be global IBS symptom improvement, with health-related quality of life and adverse effects also measured at 12, 26, and 52 weeks.
2.3. Refractory IBS
What factors contribute to the development of refractory IBS?
Why This Is Important
While most IBS patients experience short-term or intermittent symptoms, some develop chronic, severe, and treatment-resistant symptoms. Prospective studies investigating refractory IBS are limited. A large, prospective, population-based cohort study is needed to evaluate community-dwelling individuals with IBS symptoms. Assessments should include bowel symptom severity, physical and psychological symptom profiles, childhood adversity, psychiatric history, social support, quality of life, and other potential predictors. Participants should be reassessed at 12 and 24 months using similar measures to identify baseline predictors of symptom chronicity, quality of life, and healthcare utilization.
2.4. Relaxation and Biofeedback
What is the impact of relaxation and biofeedback therapies on IBS symptoms and patient outcomes?
Why This Is Important
Reviews suggest potential benefits of biofeedback and relaxation therapies for IBS symptom control, but evidence is limited. Patient representation in the Guideline Development Group supports this view based on personal experiences. Recent advancements in computer-aided biofeedback warrant further investigation. A large randomized trial comparing relaxation therapy, computer-aided biofeedback, and attention control in primary care is proposed. Participants should be adults with IBS, stratified by refractory status and randomized to treatments. The primary outcome should be global IBS symptom improvement, with health-related quality of life and adverse effects measured at 12, 26, and 52 weeks. Qualitative data on patient perceptions of their condition should also be collected.
2.5. Herbal Medicines
Are Chinese and non-Chinese herbal medicines safe and effective as first-line IBS treatments, and which is the most effective and safe option?
Why This Is Important
Reviews of herbal medicines indicate a potential positive effect on IBS symptoms, but evidence is limited and heterogeneous. A large randomized, placebo-controlled trial is proposed, comparing commonly available Chinese and non-Chinese herbal medicines (single and multiple compounds). Participants should be adults with IBS, stratified by IBS type and randomized to treatments. The primary outcome should be global IBS symptom improvement, measured using validated symptom scores, with health-related quality of life and adverse event recording. Study outcomes should be assessed at 12, 26, and 52 weeks post-intervention.
Update Information
April 2017: Recommendation 1.1.1.2 was updated to align with current guidelines on recognition and referral for suspected cancer. This update is marked as [2017]. Recommendation 1.1.1.3 was removed as it became redundant after the changes to recommendation 1.1.1.2.
February 2015: New recommendations on dietary and lifestyle advice and pharmacological therapy were added to the clinical management of IBS section.
Recommendations are marked as [2017], [new 2015], [2015], and [2008]:
- [2017] indicates updates made to align with recent guidance on cancer recognition and referral.
- [new 2015] signifies that evidence was reviewed, and a recommendation was newly added or updated.
- [2015] indicates evidence review with no change to the recommended action.
- [2008] denotes that the evidence has not been reviewed since 2008.
In the 2015 update, recommendation 1.2.2.3 was added, causing subsequent renumbering of recommendations 1.2.2.3 to 1.2.2.7 from the 2008 guideline to 1.2.2.4 to 1.2.2.8 in the 2015 update. The original 2008 recommendation numbers are preserved in the full guideline.
Strength of Recommendations
The strength of each recommendation reflects the certainty based on the balance of benefits and harms, considering the quality of evidence. The guideline uses specific wording to indicate the strength of each recommendation, reflecting the committee’s confidence that most patients would choose the recommended intervention given the evidence.
For all recommendations, NICE expects shared decision-making between healthcare professionals and patients, discussing risks, benefits, patient values, and preferences to facilitate informed choices.
Interventions That Must (or Must Not) Be Used
‘Must’ or ‘must not’ are used only when there is a legal obligation or when not following the recommendation could lead to extremely serious or life-threatening consequences.
Interventions That Should (or Should Not) Be Used – A ‘Strong’ Recommendation
‘Offer’ (or similar terms like ‘refer’ or ‘advise’) indicates confidence that an intervention will likely do more good than harm for most patients and is cost-effective. Conversely, ‘Do not offer…’ indicates confidence that an intervention will not benefit most patients.
Interventions That Could Be Used
‘Consider’ is used when an intervention is expected to do more good than harm for most patients and is cost-effective, but other options may be equally valid. The decision to use the intervention is more dependent on patient values and preferences, necessitating more detailed discussion between healthcare professionals and patients.
Recommendation Wording in Guideline Updates
NICE started using this strength-of-recommendation approach for guidelines developed after January 2009. Recommendations marked [2008] may not consistently use ‘consider’ to denote recommendation strength; refer to ‘Update information’ for labeling details.
Footnotes
[1] At the time of publication (February 2015), TCAs were not UK-licensed for this IBS indication. Prescribers should follow professional guidance, taking responsibility for their decision, and obtain documented informed consent. See GMC guidance on prescribing and managing medicines and devices for further information.
[2] At the time of publication (February 2015), neither TCAs nor SSRIs were UK-licensed for IBS. Prescribers must follow professional guidance, take responsibility for prescribing decisions, and ensure documented informed consent. Refer to GMC guidance on good practice in prescribing and managing medicines and devices for details.
Your Responsibility: These guidelines reflect NICE’s view based on careful evidence consideration. Healthcare professionals should use these guidelines alongside individual patient needs, preferences, and values. Guideline application is not mandatory and does not override professional judgment in individual patient care, in consultation with patients and their caregivers.
Local healthcare commissioners and providers are responsible for enabling guideline application when desired by professionals and patients, within local and national funding priorities, and with due regard to eliminating discrimination, advancing equality, and reducing health inequalities. These guidelines should not be interpreted in a way that conflicts with these duties.
Commissioners and providers should also promote environmental sustainability in healthcare and assess and reduce the environmental impact of implementing NICE recommendations wherever possible.
Created: February 23, 2008; Last Updated: April 2017.
