Clinical question
Do antidepressant medications improve irritable bowel syndrome (IBS) symptoms?
Bottom line
Both tricyclic antidepressants (TCAs) and selective serotonin reuptake inhibitors (SSRIs) might improve overall IBS symptoms. About 55% of patients treated with TCAs or SSRIs will benefit compared with about 35% with placebo. Only TCAs improved abdominal pain for about 60% of patients compared with about 30% with placebo. Studies of TCAs reported more side effects (drowsiness and dry mouth) than studies of SSRIs did.
Evidence
The most recent systematic review included 18 RCTs of 1127 adult patients (42% to 100% women); the IBS subtype was usually not specified. Patient-reported outcomes are presented where available.1
- Twelve RCTs of TCAs (787 patients) studied amitriptyline, imipramine, desipramine, trimipramine, doxepin, and nortriptyline versus placebo over 6 to 12 weeks.
— Global IBS symptom improvement was 57% for TCAs versus 36% for placebo (number needed to treat [NNT] of 5).
— Abdominal pain improvement was 59% for TCAs versus 28% for placebo (NNT = 4).
— Adverse events (mostly drowsiness and dry mouth) were 36% for TCAs versus 20% for placebo (number needed to harm of 7).
- Seven RCTs of SSRIs (356 patients) studied fluoxetine, paroxetine, and citalopram over 6 to 12 weeks.
— Global IBS symptom improvement was 55% for SSRIs versus 33% for placebo (NNT = 5).
— Abdominal pain improvement was 45% for SSRIs versus 26% for placebo (not statistically different).
— Adverse events were 37% for SSRIs versus 27% for placebo (not statistically different).
- Evidence was limited by small sample sizes, short study duration, and likely publication bias. Adverse events were not reported in all studies.
Context
Up to 5 million Canadian adults might have symptoms compatible with IBS.4
Canadian guidelines recommend TCAs or SSRIs irrespective of whether patients have depression or anxiety.5
Evidence for antidepressants appears stronger than for antispasmodics,6 fibre,4 low FODMAP diet,7 or probiotics.4
Newer treatments are limited by cost (linaclotide costs $560 for 90 days8 and rifaximin $330 for 14 days9) and lack of long-term safety data.10
Implementation
The fecal calprotectin test might help differentiate inflammatory bowel disease from IBS11 and appears cost effective at a 100 µg/g cutoff.12
The choice of antidepressant and dosing can be based on potential side effects. Consider TCAs for diarrhea-predominant IBS and give at night (owing to constipating and sedation effects). Consider SSRIs for constipation-predominant IBS and give during the day. Doses varied in the studies; starting low and increasing slowly based on response seems reasonable.
Notes
Tools for Practice articles in Canadian Family Physician are adapted from articles published on the Alberta College of Family Physicians (ACFP) website, summarizing medical evidence with a focus on topical issues and practice-modifying information. The ACFP summaries and the series in Canadian Family Physician are coordinated by Dr G. Michael Allan, and the summaries are co-authored by at least 1 practising family physician and are peer reviewed. Feedback is welcome and can be sent to toolsforpractice{at}cfpc.ca. Archived articles are available on the ACFP website: www.acfp.ca.
Footnotes
Competing interests
None declared
The opinions expressed in Tools for Practice articles are those of the authors and do not necessarily mirror the perspective and policy of the Alberta College of Family Physicians.
This article is eligible for Mainpro+ certified Self-Learning credits. To earn credits, go to www.cfp.ca and click on the Mainpro link.
La traduction en français de cet article se trouve à www.cfp.ca dans la table des matières du numéro d’avril 2020 à la page e129.
- Copyright© the College of Family Physicians of Canada