lubiprostone (Amitiza)

Indications

• constipation
• constipation with irritable bowel syndrome
• opioid-induced constipation

Contraindications

• history of mechanical gastrointestinal obstruction

Pregnancy category: C

Dosage

• 24 ug BID with food
• 8 ug BID (irritable bowel syndrome)

Gelcap: 8, 24 ug

Pharmacokinetics

• not absorbed appreciably

Adverse effects

• gastrointestinal
  • nausea 30%, dose-dependent
  • diarrhea 13.2%
  • abdominal distension (7.1%)
  • abdominal pain (6.7%)
  • gas (6.1%)
  • vomiting (4.6%)
  • loose stools (3.4%)
• headache (13.2%)
• dizziness (4.1%)
• peripheral edema (3.8%)
• dyspnea (2.4%)
• arthralgia (3.1%)

Drug interactions

• no drug-drug interaction studies have been done
• no cyt P450 interactions
• little is absorbed, thus drug interactions unlikely

Mechanism of action

• lubiprostone is a prostone, a prostaglandin-like molecule
• selective chloride channel activator
• activates ClC-2 chloride channels in the small intestine
• increases intestinal fluid secretion
• increases intestinal motility
• increases stool consistency

Notes

• Amitiza costs over $200/month
• only about 14% of patients respond

More general terms

• laxative