Am J Psychiatry 157:1523-1524, September 2000
© 2000 American
Paroxetine and Irritable Bowel Syndrome MICHAEL
A. KIRSCH, M.D., and ALAN K. LOUIE, M.D.
To the Editor:
Treatment with selective serotonin reuptake inhibitors has been
associated with gastrointestinal side effects, including
exacerbation of irritable bowel syndrome (1).
In contrast, we describe apparent improvement of irritable bowel syndrome correlating with paroxetine treatment and
independent of antidepressant response.
Mr. A was 44 years old when he saw his primary care
physician for cramping abdominal pain, excessive flatus, frequent
diarrhea, and an inability to gain weight (6 feet, 155 lb). These
symptoms, present for 30 years, had intensified over 1 year with
increased stress. A colonoscopy with a biopsy revealed mild active
colitis. Treatment with mesalamine, 800 mg t.i.d., for 9 weeks was not
beneficial. Irritable bowel syndrome was diagnosed, and treatment with
dicyclomine, 10 mg t.i.d., for 17 weeks was unsuccessful.
At a psychiatric evaluation Mr. A complained of gastrointestinal
symptoms, low back pain, and recent stress. He met the criteria for
major depressive disorder of moderate severity. Psychotherapy was
initiated, and paroxetine, 10 mg/day, was given for 2
weeks, increased to 20 mg/day for 3 weeks, then increased to 30 mg/day.
After 2 weeks at 20 mg/day the irritable bowel symptoms fully disappeared, and Mr.
A’s depression was partially relieved. His depressive symptoms
completely disappeared only after 2 weeks at the 30-mg/day dose.
After 1 year of treatment with paroxetine, 30 mg/day, and with his
irritable bowel syndrome and depressive symptoms in
remission, Mr. A’s paroxetine therapy was tapered over 3
months. At 5 mg/day he experienced a relapse of postprandial indigestion
and loose stools (two to four per day). One week after he discontinued
paroxetine, his typical crampy abdominal
pain and diarrhea returned, without a relapse of the depression. These
symptoms remitted when Mr. A restarted paroxetine, 30 mg/day. He remained
asymptomatic for the next 14 months. Then a second slow taper was
attempted. At 10 mg/day the irritable bowel symptoms returned, without
depression. Maintenance therapy at 20 mg/day has controlled his
irritable bowel syndrome symptoms for the past 6 months,
and he has reached his highest weight ever, 167 lb.
The patient’s irritable bowel syndrome disappeared with
paroxetine treatment and twice returned when
the dose was reduced. The slow taper of paroxetine makes it unlikely that the
relapses were actually withdrawal symptoms. The mechanism by
which paroxetine may improve
irritable bowel syndrome is unclear. On the basis
of in vitro studies, paroxetine has been found to have
anticholinergic effects that might improve bowel symptoms, but clinically, this
effect appears minimal (2).
For this patient, treatment with an anticholinergic agent,
dicyclomine, was ineffective, which raises the possibility that
paroxetine may have improved his
irritable bowel syndrome by means of a serotonergic
mechanism. To our knowledge, there are only two other reports
of irritable bowel syndrome improving with serotonergic
antidepressant treatment (3,
- Efremova I, Asnis G: Antidepressants in depressed patients
with irritable bowel syndrome (letter). Am J Psychiatry 1998;
- Pollock BG, Mulsant BH, Nebes R, Kirschner MA, Begley AE,
Mazumdar S, Reynolds CF III: Serum anticholinergicity in elderly
depressed patients treated with paroxetine or nortriptyline. Am J
Psychiatry 1998; 155:1110–1112
- Emmanuel NP, Lydiard RB, Crawford M: Treatment of
irritable bowel syndrome with fluvoxamine (letter). Am J
Psychiatry 1997; 154:711–712
- Clouse RE, Lustman PJ, Geisman RA, Alpers DH: Antidepressant
therapy in 138 patients with irritable bowel syndrome: a five-year clinical experience.
Aliment Pharmacol Ther 1994; 8:409–416[Medline]