Chemistry Reference
In-Depth Information
of the failure of lactulose suggest that short-circuiting of the colon through a leaky
gut (especially in Crohn's disease) is a plausible explanation. As such, disaccharide
prebiotics like lactulose may be less useful in IBD. Further studies in IBD are war-
ranted to clarify these issues.
Other important indications for the use of lactulose take advantage of the fact
that under normal conditions most of the sugar spills into the colon and can be used
to detect bacterial metabolism. As such, lactulose, which is universally malabsorbed
in most conditions, may be used to assess small bowel transit time
77,78
and bacte-
rial overgrowth.
79
However, these two techniques are becoming more controversial.
Because of the very small amount absorbed and excreted into the urine, lactulose
is also used to assess intestinal permeability by comparing the ratio excreted to an
amount excreted of another sugar, either mannitol
80
or rhamnose.
81
These tests are
not discussed here.
5.2.3
safety Issues with lactulose
Lactulose is considered generally safe as attested to by its long clinical use.
7
There
are few serious problems. These are outlined in Table 5.2. One of the more important
warnings is to suspend use if more than two loose bowel movements occur because rarely
hypernatremia can develop.
82,83
A more recent important safety issue has been raised in
patients taking anticoagulant medications. Lactulose may enhance the effects of these
drugs by reducing bacterial populations that produce vitamin K.
84
Several potential
problems may rarely emerge in patients using lactulose with diabetes and dyslipidemia
as outlined above. However, the clinical relevance of these latter potential problems
needs further study. Lactulose may aggravate gastro-esophageal reflux through its pos-
sible effects on upper gastrointestinal motility as outlined above
11,12,27,28
and in a recent
study published in abstract form only.
85
Finally, there have been a few cases of pneuma-
tosis intestinalis (air in the bowel wall) associated with use of lactulose.
86
Table 5.2 safety Issues with
lactulose
side Effect
Comments
refs.
overdose
More than two loose bowel movements; may
provoke hypernatremia
82, 83
enhanced anticoagulation
reduced microbial populations producing
vitamin k
84
Possible Problems
aggravation of dyslipidemia
rapid metabolism, acetate induces lipid
synthesis
45
aggravation of diabetes
Variation of other sugar contaminants; may
affect glycemic control
48
aggravation of
gastrointestinal reflux
release of peptide yy slows gastric emptying
28, 85
Pneumatosis intestinalis
tracking of air in the intestinal wall through
retained gases with insufficient bacteria to
metabolize hydrogen
86
