Katzung Laxatives
Katzung Laxatives
Katzung Laxatives
they are self-prescribed by a large portion of the population. For most people, intermittent constipation
is best prevented with a
high-fiber diet, adequate fluid intake, regular exercise, and the
heeding of nature’s call. Patients not responding to dietary changes
or fiber supplements should undergo medical evaluation before
are available, which may be used for the treatment of acute con-
stipation or to cleanse the bowel prior to medical procedures (eg,
safe for all patients. For optimal bowel cleansing, 1–2 L of solu-
tion should be ingested rapidly (over 1–2 hours) on the evening
before the procedure and again 4–6 hours before the procedure.
For treatment or prevention of chronic constipation, smaller doses
of PEG powder may be mixed with water or juices (17 g/8 oz) and
ingested daily. In contrast to sorbitol or lactulose, PEG does not
produce significant cramps or flatus.
STIMULANT LAXATIVES
Stimulant laxatives (cathartics) induce bowel movements through
a number of poorly understood mechanisms. These include direct
stimulation of the enteric nervous system and colonic electrolyte
and fluid secretion. There has been concern that long-term use of
There has been some concern that these agents may be carci-
nogenic, but epidemiologic studies do not suggest a relation to
colorectal cancer.
Diphenylmethane Derivatives
Bisacodyl is available in tablet and suppository formulations for
the treatment of acute and chronic constipation. It also is used
in conjunction with PEG solutions for colonic cleansing prior
to colonoscopy. It induces a bowel movement within 6–10 hours
when given orally and 30–60 minutes when taken rectally. It has
minimal systemic absorption and appears to be safe for acute and
long-term use.
CHLORIDE SECRETION ACTIVATORS
Lubiprostone is a prostanoic acid derivative labeled for use in
gastric emptying.
Linaclotide and plecanatide are minimally absorbed, short
and distal bowel relaxation (via nitric oxide and vasoactive intes-
tinal peptide).
channels or 5-HT1B
receptors. In three 12-week clinical trials of patients with severe
chronic constipation, it resulted in a significant increase in bowel
movements compared with placebo. The long-term efficacy and
safety of this agent require further study.