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Alosetron Side Effects

In Summary

Commonly reported side effects of alosetron include: constipation. See below for a comprehensive list of adverse effects.

For the Consumer

Applies to alosetron: oral tablet

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
Rare Incidence not known

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

Symptoms of overdose
  • Clumsiness, unsteadiness, trembling, or other problems with muscle control or coordination
  • convulsions (seizures)
  • difficulty breathing
  • shakiness and unsteady walk
  • withdrawn or socially detached behavior

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
  • Bleeding after bowel movement
  • full or bloated feeling
  • pressure in the stomach
  • swelling of abdominal or stomach area
  • uncomfortable swelling around rectal area
Incidence not known

For Healthcare Professionals

Applies to alosetron: oral tablet


-Very common (10% or more): Constipation (up to 29%)
-Common (1% to 10%): Abdominal discomfort/pain, diarrhea, nausea, GI discomfort/pain, abdominal distention, regurgitation/reflux, hemorrhoids, hemorrhoidal hemorrhage, viral gastroenteritis, flatulence
-Uncommon (0.1% to 1%): Ischemic colitis, hyposalivation, dyspeptic symptoms, GI spasms, GI lesions, serious constipation complications (obstruction, ileus, impaction, toxic megacolon, secondary bowel ischemia)
-Rare (less than 0.1%): Abnormal tenderness, colitis, proctitis, diverticulitis, positive fecal occult blood, hyperacidity, decreased GI motility and ileus, GI obstructions, oral symptoms, GI intussusception, gastritis, gastroduodenitis, gastroenteritis, ulcerative colitis
-Postmarketing reports: Impaction, ulceration, small bowel mesenteric ischemia, serious constipation complications (perforation, death)[Ref]


-Uncommon (0.1% to 1%): Tachyarrhythmia
-Rare (less than 0.1%): Arrhythmia, increased blood pressure, extrasystoles, contusion, hematoma[Ref]


-Uncommon (0.1% to 1%): Sweating, urticaria
-Rare (less than 0.1%): Hair loss/alopecia, acne/folliculitis, sweat and sebum disorders, allergic skin reaction, eczema, skin infections, dermatitis/dermatosis, nail disorders
-Postmarketing reports: Rash[Ref]


Rare (less than 0.1%): Hypothalamus and pituitary hypofunction[Ref]


-Common (1% to 10%): Urinary tract infection, urinary frequency
-Rare (less than 0.1%): Female reproductive tract bleeding and hemorrhage, reproductive infections, fungal reproductive infections, bladder inflammation, polyuria/diuresis, urinary tract hemorrhage[Ref]


Rare (less than 0.1%): Quantitative red cell or hemoglobin defects, hemorrhage[Ref]


-Common (1% to 10%): More than 2-fold elevation of ALT
-Rare (less than 0.1%): Abnormal bilirubin levels, cholecystitis
-Very rare (less than 0.01%): Hepatitis (elevated ALT, AST, alkaline phosphatase, and bilirubin)[Ref]


-Rare (less than 0.1%): Calcium and phosphate metabolism disorders, hyperglycemia, hypoglycemia, fluid disturbance[Ref]


-Common (1% to 10%): Muscle spasms
-Rare (less than 0.1%): Muscle pain, muscle stiffness, tightness/rigidity, bone/skeletal pain[Ref]

Nervous system

-Common (1% to 10%): Headache
-Rare (less than 0.1%): Memory effects, tremors, dreams, cognitive function disorders, taste disturbances, equilibrium disorders, confusion, sedation, hypoesthesia, burning sensations, hot and cold sensations[Ref]


Rare (less than 0.1%): Light sensitivity of eyes[Ref]


-Common (1% to 10%): Malaise/fatigue
-Uncommon (0.1% to 1%): Cramps, pain, temperature regulation disturbances, fungal infections[Ref]


-Uncommon (0.1% to 1%): Hypnagogic effects
-Rare (less than 0.1%): Depressive moods, sexual function disorders[Ref]


-Common (1% to 10%): Upper respiratory tract infection, nasopharyngitis, sinusitis, cough
-Uncommon (0.1% to 1%): Breathing disorders
-Rare (less than 0.1%): Ear/nose/throat infection (viral and non-viral), laryngitis[Ref]


1. "Product Information. Lotronex (alosetron)." Glaxo Wellcome, Research Triangle Park, NC.

Some side effects of alosetron may not be reported. Always consult your doctor or healthcare specialist for medical advice. You may also report side effects to the FDA.

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