Alosetron

What is Alosetron?

• Alosetron (Lotronex) is a selective serotonin 5-HT3 antagonist used largely for management of diarrhea-predominant irritable bowel syndrome rather than as an antiemetic.

Alosetron Structural Formulae V.1

Alosetron ball-and-stick model

What are the uses of this medicine?

Alosetron (Lotronex) is a medicine only for some women with severe chronic IBS whose:

• main problem is diarrhea and
• IBS symptoms have not been helped enough by other treatments.

Severe IBS includes diarrhea and 1 or more of the following:

• frequent and severe abdominal pain/discomfort,
• frequent bowel urgency or fecal incontinence,
• disability or restriction of daily activities due to IBS.

Limitations of use:

• Lotronex does not cure IBS, and it may not help every person who takes it.
• For those who are helped, Lotronex reduces lower stomach area (abdominal) pain and discomfort, the sudden need to have a bowel movement (bowel urgency), and diarrhea from IBS.
• If you stop taking Lotronex, your IBS symptoms may return within 1 or 2 weeks to what they were before you started taking Lotronex.

How does this medicine work?

Alosetron is a potent and selective 5-HT3 receptor antagonist. 5-HT3 receptors are ligand-gated cation channels that are extensively distributed on enteric neurons in the human gastrointestinal tract, as well as other peripheral and central locations. Activation of these channels and the resulting neuronal depolarization affect the regulation of visceral pain, colonic transit, and gastrointestinal secretions, processes that relate to the pathophysiology of IBS. 5-HT3 receptor antagonists such as alosetron inhibit activation of non-selective cation channels, which results in the modulation of the enteric nervous system.

Who Should Not Use this medicine ?

This medicine cannot be used in patients if: Your main IBS problem is constipation or you are constipated most of the time. You have had a serious problem from constipation. If you are constipated now, do not start taking Lotronex. You have had serious bowel blockages. You have had blood flow problems to your bowels, such as ischemic colitis. You have had blood clots. You have had Crohn's disease, ulcerative colitis, diverticulitis, or severe liver disease. You are taking fluvoxamine (LUVOX®).

What drug interactions can this medicine cause?

Tell your healthcare provider about all the medicines you take, including prescription and over-the-counter medicines, vitamins, and herbal supplements. Be sure to mention any of the following: certain antifungals such as fluconazole (Diflucan), itraconazole (Sporanox), ketoconazole (Nizoral), and voriconazole (Vfend); cimetidine (Tagamet); clarithromycin (Biaxin, in Prevpac); fluoroquinolone antibiotics including ciprofloxacin (Cipro), gatifloxacin (Tequin), levofloxacin (Levaquin), norfloxacin (Noroxin), ofloxacin (Floxin), others; hydralazine (apresoline); isoniazid (INH, Nydrazid); certain medications for human immunodeficiency virus (HIV) or acquired immunodeficiency syndrome (AIDS) such as atazanavir (Reyataz), darunavir (Prezista), fosamprenavir (Lexiva), indinavir (Crixivan), lopinavir (in Kaletra), nelfinavir (Viracept), ritonavir (Norvir, in Kaletra), saquinavir (Fortovase, Invirase), and tipranavir (Aptivus); procainamide (Procanbid, Pronestyl); and telithromycin (Ketek). fluvoxamine (Luvox) antihistamines; certain antidepressants ('mood elevators') called tricyclic antidepressants; or certain medications to treat asthma, diarrhea, lung disease, mental illness, motion sickness, overactive bladder, pain, Parkinson's disease, stomach or intestinal cramps, ulcers and upset stomach.

Is this medicine FDA approved?

Its introduction in the 1990s however, was followed by cases of severe, even life-threatening, constipation which led to its withdrawal in 2000. Alosetron was reintroduced in 2002 with restrictions on its availability and limitation to women with severe diarrhea-predominant irritable bowel syndrome.

How should this medicine be used?

Recommended dosage:

• Starting dose is 0.5 mg twice a day.
• 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.
• Discontinue Lotronex in patients who have not had adequate control of IBS symptoms after 4 weeks of treatment with 1 mg twice a day.
• Lotronex should be used with caution in patients with mild or moderate hepatic impairment and is contraindicated in patients with severe hepatic impairment.

Administration:

• Alosetron comes as a tablet to take by mouth.
• It is usually taken twice a day with or without food.
• Take alosetron at around the same times every day.
• Begin with 0.5 mg two times a day for 4 weeks to see how Lotronex affects you. You and your doctor may decide that you should keep taking this dose if you are doing well.
• Check with your doctor 4 weeks after starting Lotronex:
• If you try 0.5 mg two times a day for 4 weeks, it may not control your symptoms. If you do not get constipation or other side effects from Lotronex, your doctor may increase your dose up to 1 mg two times a day.
• If 1 mg two times a day does not work after 4 weeks, Lotronex is not likely to help you. You should stop taking it and call your doctor.
• If you miss a dose of Lotronex, just skip that dose. Do not take 2 doses the next time. Wait until the next time you are supposed to take it and then take your normal dose.

What are the dosage forms and brand names of this medicine?

This medicine is available in fallowing doasage form:

• As Tablets: 0.5 and 1 mg

This medicine is available in fallowing brand namesː

• Lotronex

What side effects can this medication cause?

The most common side effects of this medicine include:

• Constipation
• abdominal discomfort and pain
• nausea
• gastrointestinal discomfort
• pain

Some patients have developed serious bowel side effects while taking Lotronex include:

• Serious complications of constipation
• Ischemic colitis (reduced blood flow to the bowel)

What special precautions should I follow?

• Serious complications of constipation, including obstruction, ileus, impaction, toxic megacolon, and secondary bowel ischemia, have been reported with use of Lotronex. Lotronex should be discontinued immediately in patients who develop constipation.
• Ischemic colitis may occur in some patients without warning. Promptly evaluate patients with signs of ischemic colitis (e.g., rectal bleeding, bloody diarrhea, new or worsening abdominal pain). Discontinue Lotronex immediately if signs of ischemic colitis occur, such as rectal bleeding, bloody diarrhea, or new or worsening abdominal pain.
• Tell your doctor if you are constipated now, if you often have constipation, or if you have had problems resulting from constipation.
• Stop taking alosetron and call your doctor right away if you experience any of the following symptoms: constipation, new or worse pain in the abdomen (stomach area), or blood in your bowel movements.
• Patients treated with alosetron must be enrolled in a prescribing program and have regular monitoring for side effects.

What to do in case of emergency/overdose?

Symptoms of overdosage may include:

• Inhibition of the metabolic elimination and reduced first pass of other drugs might occur with overdoses of Lotronex.

Management of overdosage:

• There is no specific antidote for overdose of Lotronex. Patients should be managed with appropriate supportive therapy.

Can this medicine be used in pregnancy?

• Pregnancy Category B.
• There are, however, no adequate and well-controlled studies in pregnant women.
• Because animal reproduction studies are not always predictive of human response, Lotronex should be used during pregnancy only if clearly needed.

Can this medicine be used in children?

• Safety and effectiveness in pediatric patients have not been established.

What are the active and inactive ingredients in this medicine?

Active Ingredient:

• alosetron hydrochloride.

Inactive Ingredients:

• lactose (anhydrous), magnesium stearate, microcrystalline cellulose, and pregelatinized starch. The white film-coat for the 0.5 mg tablet contains hypromellose, titanium dioxide, and triacetin. The blue film-coat for the 1 mg tablet contains hypromellose, titanium dioxide, triacetin, and indigo carmine.

Who manufactures and distributes this medicine?

Manufactured for:

• Prometheus Laboratories Inc.
• Carroll Park Drive
• San Diego, CA

• Prometheus and Lotronex are registered trademarks of Prometheus Laboratories Inc., San Diego, CA.
• LUVOX is a registered trademark of Abbott Products, Inc., Abbott Park IL.

What should I know about storage and disposal of this medication?

• Store Lotronex between 59ºF to 86ºF (15ºC to 30ºC).
• Protect Lotronex from light and getting wet (moisture).

• Dailymed label info on Alosetron
• FDA Alosetron