Alosetron Hydrochloride

Serious warning

The strongest warning the FDA requires. It is printed in a box at the top of the label.

Quoted from the official label, section “Boxed Warning”.

Do not take it if

Quoted from the official label, section “Contraindications”.

How to take it

These directions are for this exact strength and form. Another one is different.

• Starting dose is 0.5 mg twice a day (2.1) May increase dose to 1 mg twice a day after 4 weeks if starting dosage is well tolerated but does not adequately control IBS symptoms (2.1) Discontinue alosetron tablets in patients who have not had adequate control of IBS symptoms after 4 weeks of treatment with 1 mg twice a day.
• (2.1)
• 2.1 Adult Patients To lower the risk of constipation, alosetron tablets should be started at a dosage of 0.5 mg twice a day.
• Patients who become constipated at this dosage should stop taking alosetron tablets until the constipation resolves.
• They may be restarted at 0.5 mg once a day.
• If constipation recurs at the lower dose, alosetron tablets should be discontinued immediately.
• Patients well controlled on 0.5 mg once or twice a day may be maintained on this regimen.
• If after 4 weeks the dosage is well tolerated but does not adequately control IBS symptoms, then the dosage can be increased to up to 1 mg twice a day.
• Alosetron tablets should be discontinued in patients who have not had adequate control of IBS symptoms after 4 weeks of treatment with 1 mg twice a day.
• Alosetron tablets can be taken with or without food [see Clinical Pharmacology (12.3) ] .
• Alosetron tablets should be discontinued immediately in patients who develop constipation or signs of ischemic colitis.
• Alosetron tablets should not be restarted in patients who develop ischemic colitis.
• Clinical trial and postmarketing experience suggest that debilitated patients or patients taking additional medications that decrease gastrointestinal motility may be at greater risk of serious complications of constipation.
• Therefore, appropriate caution and follow-up should be exercised if alosetron tablets are prescribed for these patients.
• Postmarketing experience suggests that elderly patients may be at greater risk for complications of constipation; therefore, appropriate caution and follow-up should be exercised if alosetron tablets are prescribed for these patients [see Warnings and Precautions (5.1) ] .
• 2.2 Patients with Hepatic Impairment Alosetron tablets are extensively metabolized by the liver and increased exposure to alosetron tablets are likely to occur in patients with hepatic impairment.
• Increased drug exposure may increase the risk of serious adverse reactions.
• Alosetron tablets should be used with caution in patients with mild or moderate hepatic impairment and is contraindicated in patients with severe hepatic impairment [see Contraindications (4) , Use in Specific Populations (8.6) ] .

Quoted from the official label, section “Dosage & Administration”.

Other warnings

Quoted from the official label, section “Warnings”.

Pregnancy and breastfeeding

Quoted from the official label, section “OTC — Pregnancy or Breast Feeding”.

Other medicines

Quoted from the official label, section “Drug Interactions”.

If you take too much

In an emergency, call your local emergency number or a poison control centre.

Quoted from the official label, section “Overdosage”.

Use in children

• Safety and effectiveness in pediatric patients have not been established. Use of alosetron hydrochloride is not recommended in the pediatric population, based upon the risk of serious complications of constipation and ischemic colitis in
• adults.

Quoted from the official label, section “Pediatric Use”.

Use in older people

• In some studies in healthy men or women, plasma concentrations were elevated by approximately 40% in individuals 65 years and older compared to young
• adults [see Warnings and Precautions (5.1) ] .
• However, this effect was not consistently observed in men.
• Postmarketing experience suggests that elderly patients may be at greater risk for complications of constipation therefore, appropriate caution and follow-up should be exercised if alosetron hydrochloride is prescribed for these patients [see Warnings and Precautions (5.1) ] .

Quoted from the official label, section “Geriatric Use”.

Side effects

• The following adverse reactions are described in more detail in other sections of the label:
• Complications of constipation [see Boxed Warning, Warnings and Precautions (5.1) ] Ischemic colitis [see Boxed Warning, Warnings and Precautions (5.2) ] Most common adverse reactions (incidence >2% and >placebo) in clinical studies were constipation, abdominal discomfort and pain, nausea and gastrointestinal discomfort and pain.
• (6.1) To report SUSPECTED ADVERSE REACTIONS, contact Amneal Pharmaceuticals at 1-877-835-5472 or FDA at 1-800-FDA-1088 or www.fda.gov/medwatch.
• 6.1 Clinical Trials Experience Because clinical trials are conducted under widely varying conditions, adverse reaction rates observed in the clinical trials of a drug cannot be directly compared to rates in the clinical trials of another drug and may not reflect the rates observed in practice.
• Patients with Irritable Bowel Syndrome:
• Table 1 summarizes adverse reactions from 22 repeat-dose studies in patients with IBS who were treated with 1 mg of alosetron hydrochloride twice daily for 8 to 24 weeks.
• The adverse reactions in Table 1 were reported in 1% or more of patients who received alosetron hydrochloride and occurred more frequently on alosetron hydrochloride than on placebo.
• A statistically significant difference was observed for constipation in patients treated with alosetron hydrochloride compared to placebo (p<0.0001).
• Table 1.
• Adverse Reactions Reported in ≥1% of Patients with Irritable Bowel Syndrome and More Frequently on Alosetron Hydrochloride 1 mg Twice Daily Than Placebo Body System Adverse Reaction Placebo (n = 2,363) Alosetron Hydrochloride 1 mg twice daily (n = 8,328) Gastrointestinal Constipation 6% 29% Abdominal discomfort and pain 4% 7% Nausea 5% 6% Gastrointestinal discomfort and pain 3% 5% Abdominal distention 1% 2% Regurgitation and reflux 2% 2% Hemorrhoids 1% 2% Gastrointestinal:
• Constipation is a frequent and dose-related side effect of treatment with alosetron hydrochloride [see Warnings and Precautions (5.1) ] .
• In clinical studies constipation was reported in approximately 29% of patients with IBS treated with 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 alosetron hydrochloride 1 mg twice daily withdrew from the studies due to constipation.
• Although the number of patients with IBS treated with 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 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 and Precautions (5.1) ] .
• In Studies 1 and 2, 9% of patients treated with alosetron hydrochloride reported constipation and 4 consecutive days with no bowel movement [see Clinical Studies (14.2) ] .
• 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 alosetron hydrochloride.
• Hepatic:
• A similar incidence in elevation of ALT (>2-fold) was seen in patients receiving alosetron hydrochloride or placebo (1.0% vs. 1.2%).
• A single case of hepatitis (elevated ALT, AST, alkaline phosphatase and bilirubin) without jaundice in a patient receiving alosetron hydrochloride was reported in a 12-week study.
• A causal association with 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 alosetron hydrochloride for longer than 6 months.
• Women with Severe Diarrhea-Predominant Irritable Bowel Syndrome:
• Table 2 summarizes the gastrointestinal adverse reactions from 1 repeat-dose study in female patients with severe diarrhea-predominant IBS who were treated for 12 weeks.
• The adverse reactions in Table 2 were reported in 3% or more of patients who received alosetron hydrochloride and occurred more frequently with alosetron hydrochloride than with placebo.
• Other events reported in 3% or more of patients who received alosetron hydrochloride and occurring more frequently with alosetron hydrochloride than with placebo included upper respiratory tract infection, viral gastroenteritis, muscle spasms, headaches and fatigue.
• Table 2.
• Gastrointestinal Adverse Reactions Reported in ≥3% of Women with Severe Diarrhea-Predominant Irritable Bowel Syndrome and More Frequently on Alosetron Hydrochloride Than Placebo Adverse Reaction Placebo (n = 176) Alosetron Hydrochloride 0.5 mg once daily (n = 175) Alosetron Hydrochloride 1 mg once daily (n = 172) Alosetron Hydrochloride 1 mg twice daily (n = 176) Constipation 5% 9% 16% 19% Abdominal pain 3% 5% 6% 7% Diarrhea 2% 3% 2% 2% Hemorrhoidal hemorrhage 2% 3% 2% 2% Flatulence 2% 2% 1% 3% Hemorrhoids 2% 1% 1% 3% Abdominal pain upper 1% 3% 1% 1% Adverse reactions reported in another study of 701 women with severe diarrhea-predominant IBS were similar to those shown in Table 2.
• Gastrointestinal adverse reactions reported in 3% or more of patients who received alosetron hydrochloride and occurring more frequently with alosetron hydrochloride than with placebo included constipation (14% and 10% of patients taking alosetron hydrochloride 1 mg twice daily or 0.5 mg as needed, respectively, compared with 2% taking placebo), abdominal pain, nausea, vomiting and flatulence.
• Other events reported in 3% or more of patients who received alosetron hydrochloride and occurring more frequently with alosetron hydrochloride than with placebo included nasopharyngitis, sinusitis, upper respiratory tract infection, urinary tract infection, viral gastroenteritis and cough.
• Constipation:
• Constipation was the most frequent adverse reaction among women with severe diarrhea-predominant IBS represented in Table 2.
• There was a dose response in the groups treated with alosetron hydrochloride in the number of patients withdrawn due to constipation (2% on placebo, 5% on 0.5 mg once daily, 8% on 1 mg once daily and 11% on 1 mg twice daily).
• Among these patients with severe diarrhea-predominant IBS treated with alosetron hydrochloride who reported constipation most (75%) reported one episode which occurred within the first 15 days of treatment and persisted for 4 to 5 days.
• Other Events Observed During Clinical Evaluation of Alosetron Hydrochloride:
• During its assessment in clinical trials, multiple and single doses of alosetron hydrochloride were administered, resulting in 11,874 subject exposures in 86 completed clinical studies.
• The conditions, dosages and duration of exposure to 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 reactions were classified using a standardized coding dictionary.
• Only those events that an investigator believed were possibly related to alosetron hydrochloride, occurred in at least 2 patients and occurred at a greater frequency during treatment with alosetron hydrochloride than during placebo administration are presented.
• Serious adverse reactions occurring in at least 1 patient for whom an investigator believed there was reasonable possibility that the event was related to treatment with alosetron hydrochloride and occurring at a greater frequency in patients treated with 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 reactions are those occurring on one or more occasion in 1/100 to 1/1,000 patients; rare adverse reactions are those occurring on one or more occasion in fewer than 1/1,000 patients.
• Although the events reported occurred during treatment with alosetron hydrochloride, they were not necessarily caused by it.
• Blood and Lymphatic: Rare: Quantitative red cell or hemoglobin defects and hemorrhage.
• 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 Precautions (5.2) ] 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.
• 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: 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.
• 6.2 Postmarketing Experience In addition to events reported in clinical trials, the following events have been identified during use of 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 alosetron hydrochloride.
• Gastrointestinal : Impaction, perforation, ulceration, small bowel mesenteric ischemia.
• Neurological : Headache.
• Skin : Rash.

Quoted from the official label, section “Adverse Reactions”.

What to discuss with your doctor

• Advise the patient to read the FDA-approved patient labeling (Medication Guide).
• Prescriber and Patient Responsibilities Patients should be fully counseled on and understand the risks and benefits of alosetron hydrochloride before an initial prescription is written.
• The patient may be educated by the prescriber or a healthcare provider under a prescriber’s direction.
• Prescribers must:
• counsel patients for whom alosetron hydrochloride is appropriate about the benefits and risks of alosetron hydrochloride and discuss the impact of IBS symptoms on the patient’s life. review the Medication Guide, which outlines the benefits and risks of alosetron hydrochloride and instruct the patient to read it carefully.
• Answer all questions the patient may have about alosetron hydrochloride.
• The complete text of the Medication Guide is printed at the end of this document. provide each patient with appropriate instructions for taking alosetron hydrochloride.
• Additional copies of the Medication Guide are available by contacting Amneal Pharmaceuticals at 1-877-835-5472 or visiting www.amneal.com.
• Patients who are prescribed alosetron hydrochloride should be instructed to:
• read the Medication Guide before starting alosetron hydrochloride and each time they refill their prescription. not start taking alosetron hydrochloride if they are constipated. immediately discontinue alosetron hydrochloride and contact their prescriber if they become constipated, or have symptoms of ischemic colitis such as new or worsening abdominal pain, bloody diarrhea, or blood in the stool.
• Contact their prescriber again if their constipation does not resolve after discontinuation of alosetron hydrochloride.
• Resume alosetron hydrochloride only if their constipation has resolved and after discussion with and the agreement of their treating prescriber. stop taking alosetron hydrochloride and contact their prescriber if alosetron hydrochloride does not adequately control IBS symptoms after 4 weeks of taking 1 mg twice a day.
• Distributed by:
• Amneal Pharmaceuticals LLC Bridgewater, NJ 08807 Rev. 05-2022-03 Dispense with Medication Guide available at:
• documents.amneal.com/mg/alosetron.pdf

Quoted from the official label, section “Patient Counseling Information”.

Strengths and forms

• FORMS AND STRENGTHS 0.5 mg and 1 mg tablets Alosetron tablets USP, 0.5 mg (0.562 mg alosetron hydrochloride, USPequivalent to 0.5 mg alosetron), are white, oval shaped, film-coated tablets debossed with “AN248” on one side and plain on the other side.
• Alosetron tablets USP, 1 mg (1.124 mg alosetron hydrochloride, USP equivalent to 1 mg alosetron), are light blue, oval shaped, film-coated tablets debossed with “AN249” on one side and plain on the other side.
• Tablets: 0.5 and 1 mg (3)

Quoted from the official label, section “Dosage Forms & Strengths”.

What it looks like and how it is packed

• Alosetron tablets USP, 0.5 mg (0.562 mg alosetron hydrochloride, USP equivalent to 0.5 mg alosetron), are supplied as white, oval shaped, film-coated tablets debossed with “AN248” on one side and plain on the other side.
• They are available as follows:
• Bottles of 30:
• NDC 65162-248-03 with child-resistant closures.
• Bottles of 500: NDC 65162-248-50 with child-resistant closures.
• Alosetron tablets USP, 1 mg (1.124 mg alosetron hydrochloride, USP equivalent to 1 mg alosetron), are supplied as light blue, oval shaped, film-coated tablets debossed with “AN249” on one side and plain on the other side.
• They are available as follows:
• Bottles of 30:
• NDC 65162-249-03 with child-resistant closures.
• Bottles of 500: NDC 65162-249-50 with child-resistant closures.
• Store at 20° to 25°C (68° to 77°F) [see USP Controlled Room Temperature].
• Protect from light and moisture.

Quoted from the official label, section “How Supplied”.

What is in it

• The active ingredient in alosetron tablets, USP is alosetron hydrochloride (HCl) USP, a potent and selective antagonist of the serotonin 5-HT 3 receptor type. Chemically, alosetron is designated as 2,3,4,5-tetrahydro-5-methyl-2-[(5-methyl-1H-imidazol-4-yl)methyl]-1H-pyrido[4,3-b]indol-1-one, monohydrochloride. Alosetron is achiral and has the empirical formula C 17 H 18 N 4 O
• HCl, representing a molecular weight of 330.8. Alosetron is a white to beige solid that has a solubility of 61 mg/mL in water, 42 mg/mL in 0.1M hydrochloric acid, 0.3 mg/mL in pH 6 phosphate buffer and <0.1 mg/mL in pH 8 phosphate buffer. The chemical structure of alosetron is:
• Alosetron tablets, USP are supplied for oral administration as 0.5 mg (white) and 1 mg (light blue) tablets. The 0.5 mg tablet contains 0.562 mg alosetron hydrochloride, USPequivalent to 0.5 mg alosetron and the 1 mg tablet contains 1.124 mg alosetron hydrochloride, USPequivalent to 1 mg of alosetron. Each tablet also contains the inactive ingredients lactose anhydrous, magnesium stearate, microcrystalline cellulose and pregelatinized starch (maize). The white film coat for the 0.5 mg tablet contains hypromellose, polyethylene glycol, polysorbate 80 and titanium dioxide. The light blue film coat for the 1 mg tablet contains FD&C blue #2, hypromellose, macrogol, polysorbate 80 and titanium dioxide. Structural Formula

Quoted from the official label, section “Description”.

Ingredients people check for

Lactose, gluten, dyes, sugars and other ingredients that matter with an allergy, intolerance or diet — as this product’s FDA label lists them.

Details

Source: NDC Directory · 2026-09-13 · not reviewed by a clinician

Source: US Food and Drug Administration, NDC Directory. Reuse terms: US government work (FDA).

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Other strengths and forms

8 products are sold under this name. Grouped by form; a number on a strength means several companies make it.

Same active substance

These contain the same substance. That does not mean one can replace another — ask a pharmacist.

See every product with Alosetron Hydrochloride