Sir: The use of selective serotonin reuptake inhibitors (SSRIs) across a wide range of psychiatric disorders is well documented in the literature.1 The SSRIs are generally well tolerated and dosed once daily, features that enhance compliance.2 However, among the common side effects of SSRIs are gastrointestinal reactions including nausea, diarrhea, loose stools, and constipation.3 Although these side effects are usually self-limiting, they may contribute to the patient's early discontinuation of the medication. I report the case of a patient with an early discontinuation of an SSRI due to gastrointestinal side effects who tolerated a second SSRI after initiating alosetron to treat the gastrointestinal symptoms at their initial onset.
Case report. Ms. A, a 28-year-old Hispanic woman, was diagnosed with dysthymia, according to DSM-IV criteria, by her family physician. She was in overall good physical health and denied the use of alcohol and illicit substances. She took no other prescription medications, took an occasional acetaminophen for headaches, but denied the use of any herbal or alternative medicine agents including supplements.
Ms. A was prescribed paroxetine, 20 mg daily, and within 2 doses began to experience frequent loose stools associated with a heightened sense of urgency. This lasted for about 4 days before she discontinued paroxetine without informing her physician. Her primary care physician initiated venlafaxine extended release (XR), 75 mg daily. Owing to loose stools and nervousness, she discontinued the venlafaxine on her own after 5 days. Her primary care physician referred her to the psychiatry service for evaluation and management of her psychiatric medications and psychotherapy. All screening laboratory values including a thyroid-stimulating hormone test were within normal limits. After discussing the available treatment options, Ms. A agreed to a trial of sertraline begun at 50 mg daily. After 2 days of treatment, Ms. A began to experience loose stools with cramping. She came into the office rather than unilaterally discontinuing the medication as she had done previously. She agreed, after informed consent, to a trial of alosetron, 1 mg b.i.d., and within 3 days her symptoms had cleared, enabling her to continue taking sertraline. Alosetron treatment was discontinued after 7 days with no untoward effects experienced by the patient.
In the case described above, loose stools, a common side effect associated with SSRIs, were treated with alosetron, a new medication used for the treatment of irritable bowel syndrome (IBS) in women. The purported mechanism of action of alosetron is blockade of the 5-HT3 receptor,4 the very receptor that is responsible for the gastrointestinal side effects associated with SSRI stimulation.5 Alosetron has been shown to decrease stool frequency and urgency in women with IBS. It appears to be well tolerated, with constipation being the most frequent side effect.6 By receiving specific treatment of an unwanted side effect, our patient was able to continue taking sertraline rather than having to discontinue it and try another antidepressant agent. The use of alosetron may be helpful in treating patients susceptible to gastrointestinal side effects associated with SSRIs. Further studies in a more controlled manner are warranted.
Conclusions and opinions expressed are those of the author and do not necessarily reflect the position or policy of the U.S. Government, Department of Defense, Department of the Army, or the U.S. Army Medical Command.
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