lubiprostone
Brand: Amitiza
Prototype Drug
Drug Class: chloride channel activator
Drug Family: GI agent
Subclass: bicyclic fatty acid (prostaglandin E1 derivative)
Organ Systems: gastrointestinal
Mechanism of Action
Activates type-2 chloride channels (ClC-2) in the apical membrane of intestinal epithelial cells, stimulating secretion of chloride-rich intestinal fluid. The resulting luminal fluid secretion softens stool and increases GI transit without affecting systemic electrolytes.
ClC-2 chloride channels (intestinal epithelium)
Indications
- chronic idiopathic constipation
- irritable bowel syndrome with constipation (IBS-C) in women ≥18 years
- opioid-induced constipation (non-cancer patients)
Contraindications
- mechanical GI obstruction
- known hypersensitivity to lubiprostone
Adverse Effects
Common
- nausea (25% — most common)
- diarrhea
- abdominal discomfort
- headache
Serious
- dyspnea (transient chest tightness within 1 hour of first dose)
- syncope
Pharmacokinetics (ADME)
| Absorption | low systemic bioavailability; acts locally |
| Distribution | minimal systemic distribution |
| Metabolism | rapidly metabolized locally in gastric epithelium by carbonyl reductase |
| Excretion | renal (primarily as metabolites) |
| Half-life | 0.9–1.4 hours |
| Onset | 24–48 hours |
| Peak | 1–2 weeks (full effect) |
| Duration | varies |
| Protein Binding | ~94% |
| Vd | minimal |
Drug Interactions
| Drug / Agent | Mechanism | Severity |
|---|---|---|
| methadone | methadone activates mu-opioid receptors reducing efficacy in opioid-induced constipation; titration may be needed | moderate |
Nursing Considerations
- Administer with food and water to reduce nausea, which is the most common side effect and often limits adherence.
- Warn patients about transient dyspnea (chest tightness, shortness of breath) that may occur within 1 hour of the first few doses; usually self-limiting within 3 hours.
- Female patients should have a negative pregnancy test before initiation; avoid use in pregnancy.
- Monitor efficacy by frequency of spontaneous bowel movements and stool consistency; response typically occurs within 24–48 hours.
Clinical Pearls
- Lubiprostone represents a unique mechanism — direct activation of intestinal chloride channels — that operates independently of the nervous system, making it effective even in neurogenic constipation.
- The IBS-C approval is specifically for adult women ≥18 years because adequate data are not available in men for this indication.
Safety Profile
Pregnancy avoid
Lactation use-with-caution
Renal Adjustment Not required
Hepatic Adjustment Required
TDM Not required
Concordance Terms
Cross-referenced clinical concepts — click any term to see all content where it appears.