After resolution of the initial episode of hepatic encephalopathy (HE), lactulose is
routinely continued indefinitely as maintenance therapy. Although widely used for this
indication, lactulose has never been shown in randomized, controlled trials to be effective
for preventing exacerbations of HE. Indeed, lactulose was found to be ineffective at
preventing HE when administered prophylactically to patients undergoing portosystemic shunt
insertion. While some patients may be lactulose dependent following an initial episode of HE,
it is likely that most could have their lactulose discontinued with no adverse consequences.
This goal is worth pursuing because lactulose is not innocuous. It has an unpleasant taste,
and it routinely produces gastrointestinal symptoms, including bloating, gas and diarrhea. In
high doses it can cause incontinence, dehydration and electrolyte derangements. Patients
universally dislike taking lactulose and often are noncompliant with treatment. A recent
trial showed that patients on lactulose had a substantial risk of hospital admissions due to
lactulose-related complications and treatment non-compliance.