Wellbutrin XL

Citalopram (Celexa®) for Irritable Bowel Syndrome

Citalopram is in a class of antidepressants called selective serotonin reuptake inhibitors. Citalopram is indicated for the treatment of depression. Citalopramis is also effective in the treatment of certain eating disorders (e.g., anorexia nervosa, bulimia), anxiety, and panic disorders. It has the potential to effectively treat substance use disorders.

Citalopram is generally sedating antidepressant, and it is considerably less activating than fluoxetine and sertraline. Citalopram represents a good balance of tolerability, efficacy, and cost.

Irritable Bowel Syndrome

Irritable bowel syndrome (IBS) is a chronic functional (NOT structural) gastrointestinal disorder characterized by abdominal pain, discomfort, and altered bowel habits.

Based on the predominant symptoms, IBS is classified as diarrhea predominant (IBS-D), constipation predominant (IBS-C), and mixed (IBS- M). Currently the exact cause of IBS is unknown.

Citalopram for IBS management

The main goal of IBS treatment is relief of symptoms. And the mainstay of IBS care is a high fiber diet.

The treatment is based on the predominant symptom of abdominal pain, constipation, or diarrhea.

The choice of medication depends on the severity of symptoms and the treatment is usually recommended when IBS symptoms significantly diminish the quality of life. There is no single medication that would target all IBS symptoms.

Selective serotonin reuptake inhibitors are used off label for the management of IBS. Antidepressants modulate

Citalopram benefits:

  • Alleviates abdominal pain and bloating13
  • Improves quality of life and overall well-being13
  • Improved pattern of bowel movements -- citalopram decreases in the number of days with urgency, straining, and feeling of incomplete evacuation.
  • Rapid onset of symptomatic benefits

Citalopram is effective in nondepressed IBS persons, suggesting that SSRIs may have peripheral benefits -- namely citalopram decreases the sensitivity of the colon to stretching and inhibits the colonic response to feeding17.

Another explanation for favorable effects of citalopram in IBS sufferers is that the drug ameliorates negative biases in information processing and this could reduce attention to gastrointestinal symptoms and modify fears that symptoms imply serious illness7.

It should be mentioned, that some clinical studies found the citalopram was not significantly better than placebo.

Citalopram dosage: 20 - 40 mg per day. Doses above 40 mg are not recommended. Citalopram is taken once daily, in the morning or evening, without regard to food.

Dosage in hepatic impairment: initiate with 20 mg once daily and titrate up to 40 mg/day only if needed.

Onset of effect: within 1-3 weeks.

List of clinical trials investigated Citalopram for IBS

  • A controlled crossover study of the selective serotonin reuptake inhibitor citalopram in irritable bowel syndrome. PubMed
  • Antidepressant therapy (imipramine and citalopram) for irritable bowel syndrome: a double-blind, randomized, placebo-controlled trial. PubMed
  • Open-label treatment with citalopram in patients with irritable bowel syndrome: a pilot study. PubMed
  • Citalopram provides little or no benefit in nondepressed patients with irritable bowel syndrome. PubMed

Pharmacological characteristics

  • Steady state: reached in about 1 week.
  • Metabolism: Citalopram is metabolized in the liver by the cytochrome P450 enzyme system to demethylcitalopram, didemethylcitalopram, citalopram N-oxide and a deaninated propionic acid derivative. These metabolites are not thought to contribute to the therapeutic action since both metabolites are less potent serotonin reuptake inhibitors than the parent compound, are present in lower concentrations and enter the brain less readily.
  • Bioavailability: approximately 80%.
  • Elimination half-life: 37 hours (range 30-42 hours). The half-life of demethylcitalopram being 2 days and 4 days for didemethylcitalopram.
  • Excretion: eliminated primarily via the liver (85%) and the remainder via the kidneys. Approximately 12% of the daily dose is excreted in urine as unchanged citalopram.


  • Lower risk of drug interactions than with some other antidepressants 3. Citalopram does not significantly affect the metabolism of other drugs. Also, its metabolism is not affected by digoxin, lithium, warfarin, or carbamazepine.
  • Probably safe for use on a long-term basis
  • Absorption is not affected by food
  • Low incidence of activating side effects
  • Less likely than other antidepressants to cause sexual dysfunction 4
  • Anxiolytic effects 15
  • Elicit relaxation of intestinal smooth muscle 16


  • Risk of QT prolongation. Citalopram is not appropriate for people with risk factors for QT-prolongation, such as structural heart disease, bradycardia, hypokalaemia, hypomagnesaemia or hypocalcaemia.
  • Weight gain and craving for carbohydrate 6.
  • Sexual side effects.
  • Citalopram should be used with caution in persons who are at risk of taking an overdose, especially those with cardiovascular disease.

Mechanism of action

Citalopram represents a racemic mixture of two enantiomers - molecules that have the same atomic framework but different spatial arrangements.

Citalopram is an antidepressant that selectively inhibits serotonin reuptake thereby potentiating serotonin neurotransmission. It is the most selective serotonin reuptake inhibitor currently available 2. It has only minimal effects on norepinephrine and dopamine neurotransmission with 3,400 times more serotonin (5-HT) activity than norepinephrine. Citalopram also has mild antagonist actions at H1 histamine receptors.


  • 1. Feighner JP, Over K. Multicenter study of citalopram in moderate-to-severe depression. J Clin Psychiatry. 1999 Dec;60(12):824-30. PubMed
  • 2. 1. Milne RJ, Goa KL. Citalopram: its pharmacodynamic and pharmacokinetic properties, and therapeutic potential in depressive illness. Drugs. Mar 1991;41(3):450-477.
  • 3. Lane RM. Pharmacokinetic drug interaction potential of SSRIs. Int Clin Psychopharmacol. 1996 Dec;11 Suppl 5:31-61.
  • 4. Arias F, Padi'n JJ, Rivas MT, Sa'nchez A. Sexual dysfunctions induced by serotonin reuptake inhibitors. Aten Primaria. 2000 Oct 15;26(6):389-94.
  • 6. Bouwer CD, Harvey BH. Phasic craving for carbohydrate observed with citalopram. Int Clin Psychopharmacol. 1996 Dec;11(4):273-8.
  • 7. Creed F. How do SSRIs help patients with irritable bowel syndrome? Gut. 2006 Aug;55(8):1065-7. PubMed
  • 13. Tack J, Broekaert D, Fischler B, Oudenhove LV, Gevers AM, Janssens J. A controlled crossover study of the citalopram in irritable bowel syndrome. Gut. 2006 Aug;55(8):1095-103. PubMed
  • 15. Izumi T, Inoue T, Kitaichi Y, Nakagawa S, Koyama T. Target brain sites of the anxiolytic effect of citalopram. Eur J Pharmacol. 2006 Mar 18;534(1-3):129-32.
  • 16. Tack J, Broekaert D, Corsetti M, Fischler B, Janssens J. Influence of acute serotonin reuptake inhibition on colonic sensorimotor function in man. Aliment Pharmacol Ther. 2006 Jan 15;23(2):265-74. PubMed
  • 17. Tack J, Broekaert D, Corsetti M, Fischler B, Janssens J. Influence of acute serotonin reuptake inhibition on colonic sensorimotor function in man. Aliment Pharmacol Ther. 2006 Jan 15;23(2):265-74. PubMed

By HealthyStock Research Group, September 2009
Medical resources reviewed: August 2018

Interesting facts



  • Generic name: Citalopram hydrobromide
  • Trade name: Celexa
  • Functional class: Antidepressant
  • Chemical class: Selective serotonin reuptake inhibitor
  • FDA approved: July 17, 1998
  • Manufacturer: Forest Pharmaceuticals, Inc.
  • Habit forming? No
  • Pregnancy risk factor: C
  • Researchers consider that SSRIs improve IBS symptoms via a different mechanism than tricyclic antidepressants.
  • Citalopram was developed by the Danish pharmaceutical firm H. Lundbeck A/S and is marketed in the U.S. by Forest Laboratories under trade name Celexa.
  • Citalopram is a highly selective inhibitor of serotonin reuptake with a negligible affinity for other neurotransmitter receptors.
  • Celexa appears to be safe to use on a long-term basis and may cause less withdrawal than other antidepressants when use is stopped.
  • Of all of the SSRIs Citalopram has the most favorable drug interactions profile because it has the least effect on the cytochrome P450 enzymes.

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