Dosing and uses of Amitiza (lubiprostone)
Adult dosage forms and strengths
capsule
- 8mcg
- 24mcg
Chronic Idiopathic Constipation
24 mcg PO q12hr
Irritable Bowel Syndrome With Constipation
Treatment in women ≥18 years
8 mcg PO q12hr
Opioid-Induced Constipation
Treatment in patients with chronic noncancer pain
24 mcg PO q12hr
Effectiveness in patients taking diphenylheptane opioids (eg, methadone) has not been established
Dosing Modifications
Hepatic impairment
- Mild: Dose adjustment not necessary
- Moderate (Child-Pugh B): Chronic idiopathic or opioid-induced constipation, 16 mcg PO q12hr; irritable bowel syndrome with constipation (IBS-C), no dosage adjustment required
- Severe (Child-Pugh C): Chronic idiopathic or opioid-induced constipation, 8 mcg PO q12hr; IBS-C, 8 mcg PO q24hr
- If starting dose is tolerated and adequate response has not been obtained after appropriate interval, dose can be escalated to full standard dose with appropriate monitoring of patient response
Administration
Administer with food and water
Pediatric dosage forms and strengths
Safety and efficacy not established
Amitiza (lubiprostone) adverse (side) effects
>10%
Nausea (29%)
Headache (12%)
Diarrhea (11%)
1-10%
Edema (3%)
Chest discomfort (2%)
Peripheral edema (1-3%)
Fatigue (2%)
Dizziness (3%)
Flatulence (4-6%)
Abdominal distress (3%)
Dyspepsia (2%)
Xerostomia (1%)
Abdominal pain (4-8%)
Loose stools (3%)
Postmarketing Reports
Allergic reactions
Asthenia
Increased heart rate
Malaise
Muscle cramps or spasms
Rash
Syncope
Frequent bowel movement
Cough
Rectal hemorrhage
Fecal incontinence
Dysguesia
Gastritis
Loss of consciousness
Hypotension
Warnings
Contraindications
Hypersensitivity
Mechanical GI obstruction
Cautions
Potential for mechanical GI obstruction
Potential for acute dyspnea
Avoid in severe diarrhea
May cause nausea and diarrhea (taking with food reduces chance of nausea); dose adjustment recommended
Patients with moderate-to-severe hepatic impairment (Child-Pugh class b or C) have higher systemic drug exposure
Pregnancy and lactation
Pregnancy category: C
Lactation: Unknown whether drug is excreted in breast milk; because lubiprostone increases fluid secretion in the intestine and intestinal motility, monitor breastfeeding infants for diarrhea
Pregnancy categories
A: Generally acceptable. Controlled studies in pregnant women show no evidence of fetal risk.
B: May be acceptable. Either animal studies show no risk but human studies not available or animal studies showed minor risks and human studies done and showed no risk.
C: Use with caution if benefits outweigh risks. Animal studies show risk and human studies not available or neither animal nor human studies done.
D: Use in LIFE-THREATENING emergencies when no safer drug available. Positive evidence of human fetal risk.
X: Do not use in pregnancy. Risks involved outweigh potential benefits. Safer alternatives exist.
NA: Information not available.
Pharmacology of Amitiza (lubiprostone)
Mechanism of action
Locally acting chloride channel activator; increases intestinal fluid secretion and intestinal motility; acts locally at apical portion of intestine
Absorption
Low systemic absorption
Peak plasma time: 1 hr
Distribution
Protein binding: 94% in vitro (may be irrelevant because of low systemic absorption)
Metabolism
Probably metabolized in stomach and jejunum by carbonyl anhydrase
Elimination
Half-life: 0.9-1.4 hr
Excretion: Urine (60%), feces (trace amounts)
