Chemistry Reference
In-Depth Information
5.2.2
Medical uses of lactulose
Actual and potential medical uses of lactulose have been described over the past
50 years. As stated, understanding of which specific function or physiological or
indirect effect through bacterial action is somewhat blurred by the lack of detailed
knowledge of host/microbial/microbial interactions in the intervening years. The
conditions and putative mechanisms are listed in Table 5.1.
As a drug, the disaccharide was initially prescribed for constipation
7,9
and is still
used for this purpose, particularly in elderly patients. The traditional explanation for the
drug effect is the induction of osmotic diarrhea. In a study by Jouet et al.,
26
a 40-g single
lactulose dose added to a meal increased both small intestinal and colonic motility, rais-
ing a possibility that a small dose had effects on gut transit. Subsequently, it was shown
by the same group that lactulose has tonic effects on the colon.
11,12
The mechanism is
not yet clear, but may involve release of peptide YY
27,28
and perhaps other gut peptides.
Table 5.1 Indications for Which lactulose Is Firmly Established and for Which
Further resear
ch May Confirm benefit
Established Indication
Comments
refs.
Constipation
osmotic effect, direct motility
7, 11, 12
Hepatic encephalopathy
osmotic effect, ammonia trapping by pH; reduced
ammonia production, altered bacterial
metabolism
7, 9, 10,
29-34
diagnostic uses
Measurement of intestinal permeability; estimate
of oral cecal transit; evaluation of intestinal
bacterial overgrowth; these last two are
controversial to an extent
77-81
Potential Indications
reduced bacterial carrier
states
shown for
Shigella
; some controversy for
Salmonella
after acceptance as indication
7, 35, 36
Metabolic effects
Controversial human studies in dyslipidemias and
diabetes; some human studies showing
enhanced mineral absorption and one study on
improvement of lactose intolerance
42-47, 49,
50, 53
reduced bacterial
translocation
Mainly based on animal data, human study for
urinary tract infections and obstructive jaundice,
proposed for prevention of complications of
chronic liver disease
57-60
antiendotoxin effect
animal models and
in vitro
evidence for reduced
tnf-
α
production
37-41
anticolorectal cancer
some human studies on bile acids and reduced
carcinogenic bacterial enzymes attenuation of
carcinogens in animal models
64-66
therapy in ibd
Prevention in animal model, minimal in humans
73-75
Note:
Potential mechanisms are listed as shown. tnf-
α
, tumor necrosis factor alpha; ibd,
inflammatory bowel disease.
