Alosetron

FDA label

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Titration May increase to 1 mg BID after 4 weeks if well tolerated but inadequate control.

Renal No adjustment needed

Hepatic Contraindicated in severe impairment; use with caution in mild–moderate.

Instructions

• Take with or without food.
• Discontinue immediately if constipation or signs of ischemic colitis (rectal bleeding, bloody diarrhea, new/worsening abdominal pain); do not resume if ischemic colitis occurs.
• If constipated, stop until it resolves; may restart at 0.5 mg QD.

Contraindications

• Constipation (do not initiate)
• History of chronic/severe constipation or its sequelae; intestinal obstruction, stricture, toxic megacolon, GI perforation/adhesions; ischemic colitis; impaired intestinal circulation, thrombophlebitis, or hypercoagulable state; Crohn's disease or ulcerative colitis; diverticulitis
• Severe hepatic impairment
• Concomitant fluvoxamine

Cautions

• Serious complications of constipation (obstruction, ileus, impaction, toxic megacolon, bowel ischemia; rarely perforation/death); higher risk in elderly, debilitated, or on GI-motility-lowering drugs
• Ischemic colitis—evaluate promptly; do not resume treatment

Adverse reactions

• Constipation (dose-related, ~29% at 1 mg BID)
• Abdominal discomfort/pain
• Nausea
• GI discomfort/pain

Pregnancy Insufficient human data; no adverse developmental effects in animal studies.

Lactation No human data; present in rat milk—monitor breastfed infant for severe constipation and blood in stools.