Irritable bowel syndrome (IBS) is a common
gastrointestinal disease characterized by
abdominal pain and change in bowel habits. IBS
diarrhea predominant (IBS-D), which is arguably the most common subset of IBS, is also associated with rectal urgency, increased frequency, abdominal bloating, and loose to watery stools. Current treatments for
diarrhea include mu-
opioid agonists (i.e.,
loperamide,
lomotil) and
bile acid sequestrants (i.e.,
cholestyramine) while treatments for
abdominal pain include
antispasmodics (i.e.,
hyoscyamine,
dicyclomine) and
tricyclic antidepressants (i.e.,
amitriptyline). There are currently 3 FDA-approved treatments for IBS-D, which have been shown to improve both
abdominal pain and
diarrhea.
Alosetron was initially approved by FDA 2000; however, its use is now limited to women with severe IBS-D symptoms refractory to other treatment.
Eluxadoline, a mixed mu-
opioid agonist, and
rifaximin, a broad spectrum gut specific
antibiotic, were both FDA approved in 2015.
Eluxadoline has been shown to relieve
abdominal pain and stool consistency in appropriate candidates. While large trials already showed the efficacy of
rifaximin in treating non-constipated IBS for bloating, stool consistency, and
abdominal pain, the recent TARGET 3 trial demonstrates that
retreatment is also effective. While these new treatments significantly expand options for patients suffering from IBS-D, there is likely to remain a need for additional safe and effective
therapies.