Background and aims. Irritable bowel syndrome (IBS) is one of the most frequent functional gastrointestinal disorders, having its subtypes related to the predominant bowel pattern: IBS with diarrhea (IBS-D), IBS with constipation (IBS-C), mixed IBS (IBS-M) or alternating IBS (IBS-A). Some patients alternate between subtypes (IBS-A). We looked for the prevalence of alternation between subtypes in patients with IBS. We also analyzed changes in pharmacological therapy specifically addressed to IBS.

Methods. We performed a retrospective observational study that included 60 patients diagnosed with IBS according to Rome III criteria. Patients were asked using a detailed structured interview about their stool form changes regarding previous six months. Alternators were defined as patients that changed IBS subtype over time (previous six months).

Results. Out of the 60 patients diagnosed with IBS, 18 patients (30%) were alternators. Of these, 8 patients (44%) changed twice the subtype. Two patients (66.66%) of the IBS-M subgroup shifted between subtypes. Eight patients (44.44%) changed medication over the six months. Four patients (22.2%) of the alternators were on double association of therapy (antispasmodics) addressed to IBS. Four patients (22.22%) discontinued medication.


Patients with IBS often change between subtypes even within six months. Alternators in our pilot study represented 30% of IBS patients. IBS-M seems to be the least stable phenotype. The rarest change is the shift between IBS-C and IBS-D. Alternators also often change their pharmacological treatment (antispasmodics).


alternators, irritable bowel syndrome, treatment