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Alosetron Side Effects

Medically reviewed by Last updated on Mar 24, 2023.

Applies to alosetron: oral tablet.


Oral route (Tablet)

Infrequent but serious gastrointestinal adverse reactions have been reported with alosetron hydrochloride, including ischemic colitis and serious complications of constipation, that resulted in hospitalization, blood transfusion, surgery, and death. Alosetron hydrochloride is indicated only for women with severe diarrhea-predominant irritable bowel syndrome (IBS) who have not responded adequately to conventional therapy. Immediately discontinue alosetron hydrochloride in patients who develop constipation or symptoms of ischemic colitis. Do not resume in patients who develop ischemic colitis. If constipation resolves, resume alosetron hydrochloride only on the advice of treating prescriber.

Serious side effects of Alosetron

Along with its needed effects, alosetron may cause some unwanted effects. Although not all of these side effects may occur, if they do occur they may need medical attention.

Check with your doctor immediately if any of the following side effects occur while taking alosetron:

More common


Incidence not known

Get emergency help immediately if any of the following symptoms of overdose occur while taking alosetron:

Symptoms of overdose

Other side effects of Alosetron

Some side effects of alosetron may occur that usually do not need medical attention. These side effects may go away during treatment as your body adjusts to the medicine. Also, your health care professional may be able to tell you about ways to prevent or reduce some of these side effects.

Check with your health care professional if any of the following side effects continue or are bothersome or if you have any questions about them:

Less common

Incidence not known

For Healthcare Professionals

Applies to alosetron: oral tablet.


The most commonly reported side effects included constipation, abdominal discomfort/pain, diarrhea, and nausea.[Ref]


Very common (10% or more): Constipation (up to 75%)

Common (1% to 10%): Abdominal discomfort, abdominal distention, abdominal pain, abdominal pain upper, diarrhea, flatulence, gastrointestinal discomfort, gastrointestinal pain, hemorrhoid hemorrhage, hemorrhoids, nausea, reflux, regurgitation, viral gastroenteritis, vomiting

Uncommon (0.1% to 1%): Dyspeptic symptoms, gastrointestinal lesions, gastrointestinal spasms, hyposalivation, ischemic colitis

Rare (0.01% to 0.1%): Abnormal tenderness, colitis, decreased gastric motility, diverticulitis, gastritis, gastroduodenitis, gastroenteritis, gastrointestinal intussusception, gastrointestinal obstruction, gastrointestinal signs/symptoms, hyperacidity, ileus, oral symptoms, positive fecal occult blood, proctitis, ulcerative colitis

Frequency not reported: Complications of colitis

Postmarketing reports: Impaction, perforation, small bowel mesenteric ischemia, ulceration[Ref]


Common (1% to 10%): Cough, nasopharyngitis, sinusitis, upper respiratory tract infection

Uncommon (0.1% to 1%): Breathing disorders

Rare (0.01% to 0.1%): Laryngitis, nose infection, throat infection, viral nose infection, viral throat infection[Ref]


Common (1% to 10%): Urinary tract infection

Uncommon (0.1% to 1%): Urinary frequency

Rare (0.01% to 0.1%): Bladder inflammation, diuresis, female reproductive tract bleeding/hemorrhage, polyuria, sexual function disorders, urinary tract hemorrhage[Ref]


Common (1% to 10%): ALT elevation

Rare (0.01% to 0.1%): Abnormal bilirubin levels, cholecystitis

Frequency not reported: Elevated alkaline phosphatase, elevated AST, elevated bilirubin, hepatitis without jaundice[Ref]


Uncommon (0.1% to 1%): Fatigue, malaise, pain, temperature regulation disturbances

Rare (0.01% to 0.1%): Cold sensation, ear infections, hot and cold sensations, viral ear infections[Ref]


Uncommon (0.1% to 1%): Sweating, urticaria

Rare (0.01% to 0.1%): Acne, allergic skin reaction, alopecia, dermatitis, dermatosis, eczema, folliculitis, hair loss, nail disorders, sebum disorders, skin infections, sweat disorders

Postmarketing reports: Rash[Ref]

Nervous system

Uncommon (0.1% to 1%): Hypnagogic effects

Rare (0.01% to 0.1%): Burning sensations, cognitive function disorder, equilibrium disorders, hypoesthesia, memory effects, sedation, taste disturbance, tremors

Frequency not reported: Headache[Ref]


Uncommon (0.1% to 1%): Cramps

Rare (0.01% to 0.1%): Bone pain, muscle pain, muscle stiffness, rigidity, skeletal pain, tightness

Frequency not reported: Muscle spasms[Ref]


Uncommon (0.1% to 1%): Tachyarrhythmias

Rare (0.01% to 0.1%): Arrhythmias, contusions, extrasystoles, hematoma, hemorrhage, increased blood pressure[Ref]


Uncommon (0.1% to 1%): Anxiety

Rare (0.01% to 0.1%): Confusion, depressive moods, dreams[Ref]


Rare (0.01% to 0.1%): Disorder of calcium metabolism, disorder of phosphate metabolism, fluid disturbances, hyperglycemia, hypofunction[Ref]


Rare (0.01% to 0.1%): Fungal infections, fungal reproductive infections, reproductive infections[Ref]


Rare (0.01% to 0.1%): Quantitative hemoglobin defects, quantitative red cell defects[Ref]


Rare (0.01% to 0.1%): Light sensitivity of eyes[Ref]


Rare (0.01% to 0.1%): Hypothalamus/pituitary hypofunction[Ref]


1. Product Information. Lotronex (alosetron). Glaxo Wellcome. 2001;PROD.

Further information

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.

Some side effects may not be reported. You may report them to the FDA.