alosetron

REMS

Severe diarrhea-predominant irritable bowel syndrome (IBS) in women who have chronic symptoms (≥6 mo), no other GI pathology, and have had no response to conventional therapy.

Action ⬆ ⬇

5-HT₃ receptors are nonselective cation channels responsible for regulation of visceral pain, colonic transit, and GI secretions. Alosetron inhibits the activation of these channels.

Therapeutic effects:

Increased colonic transit time without affecting orocecal transit time, resulting in decreased pain/discomfort and diarrhea associated with IBS.

Pharmacokinetics ⬆ ⬇

Absorption: 50–60% absorbed following oral administration.

Distribution: Widely distributed to tissues.

Metabolism/Excretion: Extensively metabolized by the liver; 13% excreted unchanged in urine.

Half-Life: 1.5 hr.

Time/Action Profile ⬆ ⬇

(pain/discomfort, diarrhea)

ROUTE	ONSET	PEAK	DURATION
PO	within 1–2 wk	up to 6 wk	1 wk‡

‡Following discontinuation.

Contraind./Precautions ⬆ ⬇

Contraindicated in:

Hypersensitivity;
Constipation;
History of chronic/severe constipation or complications due to constipation;
History of GI obstruction, stricture, toxic megacolon, perforation, and/or adhesions;
History of ischemic colitis, ↓ intestinal circulation, thrombophlebitis, or coagulation defects;
History of Crohn disease/ulcerative colitis/diverticulitis;
Severe hepatic impairment;
Concurrent use of fluvoxamine.

Use Cautiously in:

Mild or moderate hepatic impairment;
OB: Use during pregnancy only if potential maternal benefit justifies potential fetal risk;
Lactation: Use while breastfeeding only if potential maternal benefit justifies potential risk to infant;
Pedi: Safety and effectiveness not established in children;
Geri: ↑risk of constipation in older adults.

Adv. Reactions/Side Effects ⬆ ⬇

GI:

constipation

, abdominal discomfort, abdominal distention, ACUTE ISCHEMIC COLITIS , flatulence, nausea, GI viral infections, hemorrhoids, regurgitation or reflux, TOXIC MEGACOLON

Interactions ⬆ ⬇

Drug-drug:

Fluvoxamine can ↑ levels and risk of toxicity; concurrent use contraindicated.
Amiodarone, cimetidine, ciprofloxacin, clarithromycin, itraconazole, ketoconazole, ofloxacin, protease inhibitors, and voriconazole may ↑ levels and risk of toxicity; use concurrently with caution.

Route/Dosage ⬆ ⬇

PO (Adults ): 0.5 mg twice daily.

Availability ⬆ ⬇

(Generic available)

Tablets: 0.5 mg; 1 mg

Assessment ⬆ ⬇

Monitor patient for signs of constipation or ischemic colitis (new or worsening abdominal pain, bloody diarrhea, blood in stool) during therapy. Patients should not start taking alosetron if they are constipated. Discontinue therapy immediately if patient develops constipation or signs/symptoms of ischemic colitis.

Implementation ⬆ ⬇

Do not confuse Lotronex with Protonix.
PO: Administer 0.5 mg twice daily for 4 wk. If constipation occurs after starting therapy, discontinue until constipation resolves; then restart at 0.5 mg once daily (if constipation recurs at this dose, discontinue therapy). If IBS symptoms are not controlled after 4 wk, no constipation has occurred, and patient tolerates either 0.5 mg once or twice daily, dose may be ↑ to 1 mg twice daily. If symptoms are not controlled after 4 wk of 1 mg twice daily, discontinue alosetron.
Can be administered with or without food; however, administration with food may ↓ absorption by 25%.

Patient/Family Teaching ⬆ ⬇

Instruct patient to take alosetron exactly as directed. If a dose is missed, skip the dose and return to regular schedule; do not double doses. Counsel patients about the risks and benefits of alosetron and the impact of IBS symptoms on their life. Patients should read the Medication Guide before starting alosetron and each time they refill their prescription.
Caution patient to stop taking alosetron and report constipation or signs of ischemic colitis to health care professional immediately. Immediately contact health care professional again if constipation does not resolve after discontinuation of alosetron. Alosetron should be resumed only after constipation has resolved and on the advice of their health care professional. Treatment with alosetron should not be resumed in patients who develop ischemic colitis.
Advise patient to notify health care professional of all Rx or OTC medications, vitamins, or herbal products being taken and to consult with health care professional before taking other medications.
Rep: Advise women of reproductive potential to notify health care professional if pregnancy is planned or suspected or if breastfeeding.

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Pronunciation ⬇

Classifications ⬆ ⬇

Indications ⬆ ⬇