Drug Update: Irritable Bowel Syndrome - Brief Article - Statistical Data Included

0 Comments | Family Practice News, June 1, 2000 | by Mitchel L. Zoler, | Sharon Worcester

Drug treatment of irritable bowel syndrome is appropriate for patients with disabling symptoms.

Few drugs have been adequately studied for treating the syndrome, however. In general, drugs do not work very well for patients with IBS, but several agents seem to help at least some patients.

Treatment should be tailored based on whether the IBS is diarrhea predominant or constipation predominant and whether the patient has anxiety-related symptoms, abdominal pain, or impaired social function.

Treatment should also include supportive care accompanied by patient education and recommendations for lifestyle and dietary changes. Over-the-counter treatments, including psyllium-based fiber therapy, should be tried before advancing to a prescription drug. Psychological treatment is also effective for many patients.

Misoprostol is contraindicated during pregnancy and dicyclomine is contraindicated for nursing women. No dose adjustment of the other listed drugs is specifically required for patients who are pregnant, breast-feeding, or elderly. But these drugs should be used with caution in these patients.

Editor's Note:

In February, the Food and Drug Administration approved the marketing of alosetron (Lotronex) for the treatment of women with diarrhea-predominant IBS. It is the first approved agent from a new class of IBS drugs, the 5-hydroxytryptamine-3 receptor antagonists. Also in advanced development are drugs from another new class, the 5-hydroxytryptamine-4 agonists, which appear to help women and men with constipation-predominant IBS.

DRUG              DOSAGE         COST/DOSE
ANTIDIARRHEAL
Ioperamide        2-4 mg         $0.58 (2 mg) [*]
LAXATIVES
polyethylene      240 mL daily   $0.61 [*]
glycol-3350 and
electrolytes
 (COLyte)
MiraLax           17 g with 8 oz $0.84 [**]
                  water daily
sorbitol          120-240 mL     $1.33 (200 mL) [*]
                  daily
misoprostol       800-1,600      $3.60 (800 [mu]g) [*]
(Cytotec)         [mu]g/day
cisapride         20 mg q.i.d.   $5.80 [*]
 (Propulsid)
ANTICHOLINERGICS,
ANTISPASMODICS
dicyclomine       40 mg q.i.d.   $2.32 (160 mg) [*]
hydrochloride
hyoscyamine       0.125-0.25 mg  $1.28 (1 mg) [*]
sulfate           every 4 hours
hyoscyamine       0.375 mg       $1.00 [*]
sulfate, extended b.i.d.
release
PSYCHOACTIVES
amitriptyline     25-150 mg      $0.38 (100 mg) [*]
hydrochloride     at bedtime
desipramine       25-150 mg      $1.07 (100 mg) [*]
hydrochloride     at bedtime
paroxetine        10-50 mg/day   $2.23 (20 mg) [*]
hydrochloride
 (Paxil)
DRUG              COMMENT [ ]
ANTIDIARRHEAL
Ioperamide        For diarrhea-predominant IBS, as needed,
                  either after a diarrhea episode or
                  before social situations if there
                  is concern about diarrhea. Avoid unless
                  diarrhea causes functional disability.
LAXATIVES
polyethylene      May help constipation-predominant IBS,
glycol-3350 and   but try OTC preparations first. Many
electrolytes      patients don't like the taste.
 (COLyte)
MiraLax           New to the market in 1999. Alternative
                  to COLyte for patients with
                  constipation; tastes better, but
                  doesn't have COLyte's electrolytes.
sorbitol          Sometimes used for severe constipation,
                  but produces more gas and bloating
                  than most patients can tolerate.
misoprostol       Only for the most refractory cases of
(Cytotec)         severe constipation. Evaluate patients
                  for colonic inertia before use.
                  Contraindicated in pregnancy. Use by
                  nursing women is not advised. Use
                  with caution in women of childbearing age.
cisapride         For severe constipation if over-the-
 (Propulsid)      counter remedies are ineffective, but
                  not very effective for IBS. Less gas and
                  bloating than with other treatments
                  such as sorbitol.
ANTICHOLINERGICS,
ANTISPASMODICS
dicyclomine       Relieves smooth muscle spasms of the
hydrochloride     GI tract. Has several contraindications,
                  including use by nursing women.
                  Starting dosage is 20 mg q.i.d.
                  Adverse effects may limit reaching
                  target dosage.
hyoscyamine       For severe pain with spasms. Don't
sulfate           exceed 12 doses per day. Has several
                  contraindications and precautions.
hyoscyamine       Longer-acting form. For severe pain
sulfate, extended with spasms. Has several
release           contraindications and precautions.
PSYCHOACTIVES
amitriptyline     Tricyclic antidepressant. May help
hydrochloride     patients with severe pain who don't
                  respond to hyoscyamine sulfate. Only
                  for patients with diarrhea-predominant
                  IBS because anticholinergic side
                  effects can aggravate constipation.
desipramine       Alternative tricyclic antidepressant
hydrochloride     with less sedative effect.
paroxetine        Good for patients with severe pain
hydrochloride     and anxiety-related IBS symptoms. A
 (Paxil)          selective serotonin reuptake
                  inhibitor; another agent from class
                  could be used instead, but this has
                  best experience for indication.