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Last reviewed on RxList: 11/28/2018
Lotronex Side Effects Center

Last reviewed on RxList 11/28/2018

Lotronex (alosetron hydrochloride) blocks the action of a chemical called serotonin in the intestines, slowing the movement of stools (bowel movements) through the intestines and is used to treat severe, chronic irritable bowel syndrome (IBS) in women who have had diarrhea as the main symptom for at least 6 months, and should be used only in women who have tried other IBS treatments without success. Lotronex has not been shown to be effective in men with IBS. Common side effects of Lotronex include:

  • headache
  • stomach upset or discomfort
  • hemorrhoids
  • bloating
  • gas
  • nausea
  • constipation
  • burping with heartburn
  • or skin rash

To lower the risk of constipation, Lotronex should be started at a dosage of 0.5 mg twice a day. If, after 4 weeks, the dosage is well tolerated but does not adequately control IBS symptoms, then it may be increased to up to 1 mg twice a day. Lotronex may interact with fluvoxamine, cimetidine, ketoconazole, itraconazole, voriconazole, isoniazid, hydralazine, procainamide, clarithromycin, telithromycin, HIV medicines, nelfinavir, or antibiotics. Tell your doctor all medications and supplements you use. Lotronex should be used only when prescribed during pregnancy. It is unknown if this drug passes into breast milk. Consult your doctor before breastfeeding.

Our Lotronex (alosetron hydrochloride) Side Effects Drug Center provides a comprehensive view of available drug information on the potential side effects when taking this medication.

This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.

Lotronex Consumer Information

Get emergency medical help if you have signs of an allergic reaction: hives; difficulty breathing; swelling of your face, lips, tongue, or throat.

Serious or fatal side effects on the stomach and intestines have occurred in some people taking alosetron. In rare cases, alosetron has caused severe constipation, or ischemic colitis (caused by reduced blood flow to the intestines).

Stop taking alosetron and call your doctor right away if you develop:

  • new or worsening constipation;
  • stomach pain;
  • bright or dark red blood in your stools; or
  • bloody diarrhea.

You may need to permanently discontinue alosetron if you have these side effects.

Older adults and those who are ill or debilitated may be more likely to have serious complications from constipation.

Common side effects may include:

  • constipation;
  • nausea; or
  • pain or discomfort in your stomach or intestines.

This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.

Read the entire detailed patient monograph for Lotronex (Alosetron Hydrochloride)

Lotronex Professional Information


Table 1 summarizes adverse events from 22 repeat-dose studies in patients with IBS who were treated with 1 mg of LOTRONEX (alosetron hydrochloride) twice daily for 8 to 24 weeks. The adverse events in Table 1 were reported in 1% or more of patients who received LOTRONEX (alosetron hydrochloride) and occurred more frequently on LOTRONEX (alosetron hydrochloride) than on placebo. A statistically significant difference was observed for constipation in patients treated with LOTRONEX (alosetron hydrochloride) compared to placebo (p < 0.0001).

Table 1. Adverse Events Reported in ≥ 1% of IBS Patients and More Frequently on LOTRONEX (alosetron hydrochloride) 1 mg B.I.D. Than Placebo

Body System
Adverse Event
LOTRONEX (alosetron hydrochloride)
1 mg B.I.D.
(n = 8,328)
(n = 2,363)
  Constipation 29% 6%
  Abdominal discomfort and pain 7% 4%
  Nausea 6% 5%
  Gastrointestinal discomfort and pain 5% 3%
  Abdominal distention 2% 1%
  Regurgitation and reflux 2% 2%
  Hemorrhoids direction. 2% 1%

Gastrointestinal: Constipation is a frequent and dose-related side effect of treatment with LOTRONEX (see WARNINGS). In clinical studies constipation was reported in approximately 29% of IBS patients treated with LOTRONEX (alosetron hydrochloride) 1 mg twice daily (n = 9,316). This effect was statistically significant compared to placebo (p < 0.0001). Eleven percent (11%) of patients treated with LOTRONEX (alosetron hydrochloride) 1 mg twice daily withdrew from the studies due to constipation. Although the number of IBS patients treated with LOTRONEX (alosetron hydrochloride) 0.5 mg twice daily is relatively small (n = 243), only 11% of those patients reported constipation and 4% withdrew from clinical studies due to constipation. Among the patients treated with LOTRONEX (alosetron hydrochloride) 1 mg twice daily who. reported constipation, 75% reported a single episode and most reports of constipation (70%) occurred during the first month of treatment with the median time to first report of constipation onset of 8 days. Occurrences of constipation in clinical trials were generally mild to moderate in intensity, transient in nature, and resolved either spontaneously with continued treatment or with an interruption of treatment. However, serious complications of constipation have been reported in clinical studies and in postmarketing experience (see BOXED WARNING and WARNINGS). In Studies 1 and 2, 9% of patients treated with LOTRONEX (alosetron hydrochloride) reported constipation and 4 consecutive days with no bowel movement (see Clinical Trials). Following interruption of treatment, 78% of the affected patients resumed bowel movements within a 2-day period and were able to re-initiate treatment with LOTRONEX (alosetron hydrochloride) .

Hepatic: A similar incidence in elevation of ALT ( > 2-fold) was seen in patients receiving LOTRONEX (alosetron hydrochloride) or placebo (1.0% vs. 1.2%). A single case of hepatitis (elevated ALT, AST, alkaline phosphatase, and bilirubin) without jaundice was reported in a 12-week study. A causal association with LOTRONEX (alosetron hydrochloride) has not been established.

Long-Term Safety: Patient experience in controlled clinical trials is insufficient to estimate the incidence of ischemic colitis in patients taking LOTRONEX (alosetron hydrochloride) for longer than 6 months.

Other Events Observed During Clinical Evaluation of LOTRONEX (alosetron hydrochloride) : During its assessment in clinical trials, multiple and single doses of LOTRONEX (alosetron hydrochloride) were administered resulting in 11,874 subject-exposures in 86 completed clinical studies. The conditions, dosages, and duration of exposure to LOTRONEX (alosetron hydrochloride) varied between trials, and the studies included healthy male and female volunteers as well as male and female patients with IBS and other indications.

In the listing that follows, reported adverse events were classified using a standardized coding dictionary. Only those events that an investigator believed were possibly related to alosetron, occurred in at least 2 patients, and occurred at a greater frequency during treatment with LOTRONEX (alosetron hydrochloride) than during placebo administration are presented. Serious adverse events occurring in at least 1 patient for whom an investigator believed there was reasonable possibility that the event was related to alosetron treatment and occurring at a greater frequency in LOTRONEX (alosetron hydrochloride) than placebo-treated patients are also presented.

In the following listing, events are categorized by body system. Within each body system, events are presented in descending order of frequency. The following definitions are used: Infrequent adverse events are those occurring on one or more occasion in 1/100 to 1/1,000 patients; Rare adverse events are those occurring on one or more occasion in fewer than 1/1,000 patients.

Although the events reported occurred during treatment with LOTRONEX (alosetron hydrochloride) , they were not necessarily caused by it.

Blood and Lymphatic: Rare: Quantitative red cell or hemoglobin defects, hemorrhage, and lymphatic signs and symptoms.

Cardiovascular: Infrequent: Tachyarrhythmias. Rare: Arrhythmias, increased blood pressure, and extrasystoles.

Drug Interaction, Overdose, and Trauma: Rare: Contusions and hematomas.

Ear, Nose, and Throat: Rare: Ear, nose, and throat infections; viral ear, nose, and throat infections; and laryngitis.

Endocrine and Metabolic: Rare: Disorders of calcium and phosphate metabolism, hyperglycemia, hypothalamus/pituitary hypofunction, hypoglycemia, and fluid disturbances.

Eye: Rare: Light sensitivity of eyes.

Gastrointestinal: Infrequent: Hyposalivation, dyspeptic symptoms, gastrointestinal spasms, ischemic colitis (see WARNINGS), and gastrointestinal lesions. Rare: Abnormal tenderness, colitis, gastrointestinal signs and symptoms, proctitis, diverticulitis, positive fecal occult blood, hyperacidity, decreased gastrointestinal motility and ileus, gastrointestinal obstructions, oral symptoms, gastrointestinal intussusception, gastritis, gastroduodenitis, gastroenteritis, and ulcerative colitis.

Hepatobiliary Tract and Pancreas: Rare: Abnormal bilirubin levels and cholecystitis.

Lower Respiratory: Infrequent: Breathing disorders. Rare: Viral respiratory infections.

Musculoskeletal: Rare: Muscle pain; muscle stiffness, tightness and rigidity; and bone and skeletal pain.

Neurological: Infrequent: Hypnagogic effects. Rare: Memory effects, tremors, dreams, cognitive function disorders, disturbances of sense of taste, disorders of equilibrium, confusion, sedation, and hypoesthesia.

Non-Site Specific: Infrequent: Malaise and fatigue, cramps, pain, temperature regulation disturbances. Rare: General signs and symptoms, non-specific conditions, burning sensations, hot and cold sensations, cold sensations, and fungal infections.

Psychiatry: Infrequent: Anxiety. Rare: Depressive moods.

Reproduction: Rare: Sexual function disorders, female reproductive tract bleeding and hemorrhage, reproductive infections, and fungal reproductive infections.

Skin: Infrequent: Sweating and urticaria. Rare: Hair loss and alopecia; acne and folliculitis; disorders of sweat and sebum; allergic skin reaction; eczema; skin infections; dermatitis and dermatosis; and nail disorders.

Urology: Infrequent: Urinary frequency. Rare: Bladder inflammation; polyuria and diuresis; and urinary tract hemorrhage.

Postmarketing Experience: The following events have been identified during use of LOTRONEX (alosetron hydrochloride) in clinical practice. Because they were reported voluntarily from a population of unknown size, estimates of frequency cannot be made. These events have been chosen for inclusion due to a combination of their seriousness, frequency of reporting, or potential causal connection to LOTRONEX (alosetron hydrochloride) .

Gastrointestinal: Constipation, ileus, impaction, obstruction, perforation, ulceration, ischemic colitis, small bowel mesen-teric ischemia (see WARNINGS).

Neurological: Headache.

Skin: Rash.

Drug Abuse And Dependence

LOTRONEX (alosetron hydrochloride) has no known potential for abuse or dependence.

Read the entire FDA prescribing information for Lotronex (Alosetron Hydrochloride)

Related Resources for Lotronex

Read the Lotronex User Reviews »

© Lotronex Patient Information is supplied by Cerner Multum, Inc. and Lotronex Consumer information is supplied by First Databank, Inc., used under license and subject to their respective copyrights.

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