Amitiza (Lubiprostone) Dosing for Chronic Idiopathic Constipation (CIC)
For adults with chronic idiopathic constipation (CIC), the recommended dosage of Amitiza (lubiprostone) is 24 mcg twice daily taken with food and water. 1, 2
Dosing Regimen Details
- The FDA-approved dose for CIC is 24 mcg twice daily 1
- Lubiprostone should be taken with food and water to reduce the risk of nausea 2
- Capsules should be swallowed whole and not broken apart or chewed 1
- The duration of treatment in clinical trials was 4 weeks, but the FDA drug label does not provide a specific time limit for therapy 2
Dose Adjustments
- Patients with moderate to severe hepatic impairment should receive a reduced dose of 8 mcg twice daily 2
- No dose adjustment is needed for elderly patients, as efficacy in persons 65 years and older is comparable to the overall population 2
Mechanism of Action
- Lubiprostone is a chloride channel activator that works by increasing intestinal fluid secretion and accelerating gastrointestinal transit 2, 3
- It acts locally within the intestinal tract with minimal systemic absorption 2, 4
- Effects generally manifest within 2 days in patients who respond to treatment 2
Efficacy
- Clinical trials demonstrated that lubiprostone resulted in an increased number of spontaneous bowel movements (SBMs) per week compared with placebo (MD 1.98,95% CI 1.17–2.79) 2, 5
- Lubiprostone increases responder rates (RR 1.67,95% CI 1.36–2.06) 2
- Improves stool form and consistency as measured on a 0-4 point scale 2, 5
- Also improves abdominal discomfort and bloating, which are bothersome symptoms in some individuals with CIC 2
Side Effects and Precautions
- Nausea is the most common adverse event (reported in up to 35% of individuals), but is typically mild to moderate 2, 6
- The risk of nausea is dose-dependent and can be reduced when taken with food and water 2, 6
- Only about 5% of patients discontinue therapy due to nausea 2
- Patients may be at increased risk of diarrhea leading to discontinuation of treatment compared with placebo 2
- Contraindicated in patients with known or suspected mechanical gastrointestinal obstruction 1, 2
- Dyspnea may occur within an hour of the first dose but generally resolves within 3 hours 1
Clinical Pearls
- Lubiprostone is suggested for adults with CIC who do not respond to over-the-counter (OTC) agents 2
- Can be used as a replacement for or as an adjunct to OTC agents 2
- For IBS-C, a lower dose of 8 mcg twice daily is recommended, highlighting the importance of using the correct dose for the specific indication 2, 7
- Periodic assessment of the need for continued therapy is recommended 1
- Instruct patients to discontinue lubiprostone and contact their healthcare provider if severe diarrhea occurs during treatment 1