Amitiza (Lubiprostone)
lubiprostone
Indications
| Indication | Approved Population | Therapy Type | Status |
|---|---|---|---|
| Chronic idiopathic constipation (CIC) | Adults | Monotherapy | FDA Approved |
| Opioid-induced constipation (OIC) | Adults with chronic non-cancer pain | Monotherapy (adjunctive to opioid) | FDA Approved |
| Irritable bowel syndrome with constipation (IBS-C) | Women ≥18 years only | Monotherapy | FDA Approved |
Lubiprostone was the first intestinal secretagogue approved in the United States, receiving FDA approval for CIC in January 2006, followed by IBS-C in April 2008 and OIC in April 2013. It remains the only secretagogue with an FDA-approved indication for opioid-induced constipation. The IBS-C indication is limited to women because pivotal trials did not enrol sufficient men to demonstrate efficacy in that subgroup. For OIC, effectiveness has not been established in patients taking diphenylheptane opioids such as methadone. The AGA/ACG 2023 CIC guideline recommended lubiprostone conditionally (based on low-certainty evidence), whereas linaclotide, plecanatide, and prucalopride received strong recommendations.
Pediatric functional constipation: A Phase 3 trial in patients 6–17 years did not meet its primary efficacy endpoint (FDA PI). Evidence quality: Low (negative trial).
OIC in patients on methadone: Nonclinical data show methadone reduces ClC-2 activation by lubiprostone; pooled Phase 3 analysis showed no benefit over placebo in the methadone subgroup. Evidence quality: Low.
Dosing
Standard Adult Dosing
| Clinical Scenario | Starting Dose | Maintenance Dose | Maximum Dose | Notes |
|---|---|---|---|---|
| CIC — adult | 24 mcg twice daily | 24 mcg twice daily | 48 mcg/day | Take with food and water to reduce nausea Swallow capsules whole; do not crush or chew |
| OIC — chronic non-cancer pain | 24 mcg twice daily | 24 mcg twice daily | 48 mcg/day | Not established for methadone-treated patients Bypasses opioid-mediated antisecretory action via direct ClC-2 activation |
| IBS-C — women only | 8 mcg twice daily | 8 mcg twice daily | 16 mcg/day | Approved for women ≥18 years only; lower dose reflects IBS-C dose-finding data Periodically reassess need for continued therapy |
Hepatic Impairment Dose Adjustments
| Clinical Scenario | Starting Dose | Maintenance Dose | Maximum Dose | Notes |
|---|---|---|---|---|
| CIC or OIC — moderate hepatic impairment (Child-Pugh B) | 16 mcg twice daily | 16–24 mcg twice daily | 48 mcg/day | Escalate to full dose if tolerated and response inadequate Markedly higher M3 exposure in moderate impairment |
| CIC or OIC — severe hepatic impairment (Child-Pugh C) | 8 mcg twice daily | 8–24 mcg twice daily | 48 mcg/day | Escalate cautiously with monitoring; increased adverse events in severe impairment |
| IBS-C — moderate hepatic impairment (Child-Pugh B) | 8 mcg twice daily | 8 mcg twice daily | 16 mcg/day | No adjustment needed |
| IBS-C — severe hepatic impairment (Child-Pugh C) | 8 mcg once daily | 8 mcg once–twice daily | 16 mcg/day | Start once daily; escalate to twice daily if tolerated and response inadequate |
Nausea is the most frequent adverse effect of lubiprostone (up to 29% in CIC). Always instruct patients to take the capsule with food and water, which substantially reduces nausea incidence. Nausea rates are lower in men (8%) and elderly patients (19%) compared to the overall CIC population (29%). If nausea persists, some clinicians empirically try once-daily dosing or a temporary dose reduction, though these approaches are not formally studied. Do not crush or break the soft gelatin capsules.
Pharmacology
Mechanism of Action
Lubiprostone is a bicyclic fatty acid derived from prostaglandin E1 that acts as a locally-acting chloride channel activator. It specifically activates type-2 chloride channels (ClC-2) on the apical membrane of intestinal epithelial cells in a protein kinase A-independent manner. This activation enhances chloride-rich fluid secretion into the intestinal lumen without altering serum sodium or potassium concentrations, thereby increasing intestinal motility and facilitating stool passage. Importantly, lubiprostone activates ClC-2 channels at the apical surface of epithelial cells, bypassing the antisecretory action of opioids that act via suppression of secretomotor neurons — this is the pharmacological basis for its efficacy in opioid-induced constipation. Additionally, ClC-2 activation has been shown to stimulate recovery of mucosal barrier function and reduce intestinal permeability through restoration of tight junction protein complexes in preclinical models.
ADME Profile
| Parameter | Value | Clinical Implication |
|---|---|---|
| Absorption | Parent drug below quantitation (10 pg/mL); M3 metabolite: Tmax ~1.1 h, Cmax 41.5 pg/mL after 24 mcg; food reduces Cmax by 55% but not AUC | Drug acts locally at the intestinal epithelium; food administration recommended to reduce nausea (not for PK reasons) |
| Distribution | ~94% protein bound; localized to GI tract with negligible systemic distribution | Despite measurable protein binding in vitro, systemic levels are too low for clinically meaningful tissue distribution |
| Metabolism | Rapidly metabolized by 15-position reduction, α-chain β-oxidation, and ω-chain ω-oxidation; M3 formed via microsomal carbonyl reductase (not CYP enzymes); M3 accounts for <10% of dose | No CYP-mediated metabolism; however, M3 has measurable plasma levels, and hepatic impairment increases M3 exposure — hence the need for dose reduction in moderate/severe liver disease |
| Elimination | Primarily via urine (60%) and feces (30%) within 24 h as metabolites after radiolabeled dose; M3 half-life 0.9–1.4 h | Rapid elimination; no accumulation with twice-daily dosing; no renal dose adjustment needed (M3 exposure unchanged in severe renal impairment) |
Side Effects
| Adverse Effect | Incidence | Clinical Note |
|---|---|---|
| Nausea | 29% (CIC); 11% (OIC); 8% (IBS-C) | Most common AE across all indications; severe in 4% (CIC), 1% (OIC/IBS-C); d/c rate: 9% (CIC), 2% (OIC), 1% (IBS-C); lower in males (8%) and elderly (19%); reduced by taking with food |
| Diarrhea | 12% (CIC); 8% (OIC); 7% (IBS-C) | Severe diarrhea in 2% (CIC/OIC), <1% (IBS-C); d/c rate: 2% (CIC), 1% (OIC), <1% (IBS-C) |
| Headache | 11% (CIC) | Placebo rate was 5%; not reported as ≥4% in OIC or IBS-C trials |
| Adverse Effect | Incidence | Clinical Note |
|---|---|---|
| Abdominal pain | 8% (CIC); 4% (OIC); 5% (IBS-C) | Includes abdominal tenderness and discomfort; placebo rate 1–5% across indications |
| Abdominal distension | 6% (CIC); 3% (OIC/IBS-C) | Usually self-limiting with continued treatment |
| Flatulence | 6% (CIC); 4% (OIC) | Related to increased fluid secretion in the lumen |
| Vomiting | 3% (CIC/OIC) | More common at higher doses; taking with food may help |
| Edema / peripheral edema | 3% (CIC); 1% (OIC) | Mechanism unclear; not typically clinically significant |
| Dizziness | 3% (CIC) | May be related to prostaglandin-like effects or volume shifts |
| Dyspnea | 3% (CIC); 1% (OIC); <1% (IBS-C) | Chest tightness sensation; onset within 30–60 min of dosing; resolves within hours but may recur; does not represent bronchospasm |
| Chest discomfort/pain | 2% (CIC) | Likely related to dyspnea-type prostaglandin effect rather than cardiac origin |
| Dyspepsia | 2% (CIC) | May overlap with nausea; take with food |
| Fatigue | 2% (CIC) | Self-limiting in most patients |
| Adverse Effect | Estimated Frequency | Typical Onset | Required Action |
|---|---|---|---|
| Syncope and hypotension | Rare (postmarketing); some hospitalizations | Within 1 hour of first or subsequent doses; may be preceded by diarrhea/vomiting | Discontinue lubiprostone; rehydrate; evaluate cardiovascular status; be cautious with concomitant antihypertensives |
| Ischemic colitis | Very rare (postmarketing) | Variable | Discontinue immediately; urgent GI evaluation; supportive care |
| Hypersensitivity (rash, swelling, throat tightness) | Very rare (postmarketing) | Any time | Discontinue; standard allergy management |
Dyspnea has been reported in up to 3% of CIC patients and is unique to lubiprostone among intestinal secretagogues. It typically presents as a sensation of chest tightness and difficulty inhaling, with acute onset within 30–60 minutes of dosing. It is not true bronchospasm and does not appear to represent a pulmonary or cardiac event. It generally resolves within a few hours but may recur with subsequent doses. Instruct patients to report this symptom so that the prescriber can determine whether to continue therapy.
Drug Interactions
Lubiprostone is not metabolized by cytochrome P450 enzymes, and its primary metabolite M3 is formed by microsomal carbonyl reductase. No formal in vivo drug interaction studies have been conducted. However, one pharmacodynamic interaction of clinical importance has been identified in nonclinical studies involving diphenylheptane opioids.
Monitoring
- Nausea ToleranceFirst 1–2 weeks
RoutineNausea is the leading cause of discontinuation (9% in CIC). Confirm the patient is taking the capsule with food and water. If nausea persists beyond 2 weeks and is intolerable, consider switching to a GC-C agonist or prucalopride. - Stool PatternWeeks 1–4, then as needed
RoutineAssess stool frequency and consistency. Avoid use in patients with pre-existing severe diarrhea. If severe diarrhea develops, discontinue and rehydrate. - Blood PressureIf dizziness or syncope reported
Trigger-basedSyncope and hypotension have been reported postmarketing, sometimes requiring hospitalization. Risk may be higher in patients on antihypertensives. - DyspneaAfter first dose and subsequent doses
Trigger-basedIf the patient reports chest tightness or difficulty breathing within 30–60 minutes of dosing, this is likely the known dyspnea effect (not bronchospasm). It typically self-resolves within hours but recurs with repeat dosing. Determine if the patient can tolerate ongoing therapy. - Hepatic FunctionBaseline (for dose selection)
RoutineAssess hepatic function before initiating therapy to determine if dose reduction is needed. Patients with moderate or severe hepatic impairment have markedly higher M3 exposure and increased adverse event incidence. - Pregnancy StatusBefore initiation in women of childbearing potential
RoutineLubiprostone caused dose-dependent fetal loss in guinea pigs. Confirm negative pregnancy test before starting therapy; women should use effective contraception during treatment.
Contraindications & Cautions
Absolute Contraindications
- Known or suspected mechanical gastrointestinal obstruction: Evaluate patients with symptoms suggestive of obstruction before initiating therapy.
Relative Contraindications (Specialist Input Recommended)
- Pregnancy: Dose-dependent fetal loss occurred in guinea pigs at doses as low as 0.2 times the MRHD. Use only if benefit clearly outweighs risk. Confirm negative pregnancy test before initiation.
- Severe diarrhea: The FDA label explicitly states to avoid use in patients with severe diarrhea.
- IBS-C in male patients: Not approved for men (insufficient trial data to confirm efficacy in this subgroup).
Use with Caution
- Moderate to severe hepatic impairment: Dose reduction required; increased M3 exposure and higher adverse event incidence with greater hepatic dysfunction.
- Patients on antihypertensives or with orthostatic hypotension risk: Syncope and hypotension have been reported postmarketing, particularly in patients with concomitant volume depletion or BP-lowering medications.
- Lactation: Lubiprostone and M3 were not detected in animal milk, but if present in human milk, it could cause diarrhea in the breastfed infant. Monitor infants for diarrhea.
Unlike linaclotide and plecanatide, lubiprostone does not carry an FDA boxed warning. There is no specific pediatric dehydration risk warning comparable to the GC-C agonists, as the mechanism of action is different (ClC-2 activation rather than GC-C agonism). However, safety and efficacy have not been established in pediatric patients, and a Phase 3 pediatric functional constipation trial failed to meet its primary endpoint.
Patient Counselling
Purpose of Therapy
Lubiprostone works by activating specific chloride channels in the lining of your intestine, which increases fluid secretion and helps move stool through more easily. Unlike some newer medications in this class, it also works in patients whose constipation is caused by opioid pain medication. Improvement in bowel movements can occur as early as the first day of treatment.
How to Take
Take your capsule twice daily — once in the morning and once in the evening — always with food and a glass of water. This significantly reduces the chance of nausea. Swallow the capsule whole; do not crush, break, or chew it. Your doctor should periodically reassess whether you still need to continue treatment.
Sources
- AMITIZA (lubiprostone) capsules, for oral use. Full Prescribing Information. Mallinckrodt Pharmaceuticals. Revised January 2024. Drugs.com PIPrimary source for all dosing, adverse reaction rates, contraindications, hepatic adjustments, and pharmacokinetic data.
- Amitiza (lubiprostone) FDA Approval History. Drugs.com. Accessed April 2026. Drugs.comTimeline of FDA regulatory actions from CIC approval (Jan 2006) through OIC (Apr 2013).
- Johanson JF, Ueno R. Lubiprostone, a locally acting chloride channel activator, in adult patients with chronic constipation: a double-blind, placebo-controlled, dose-ranging study to evaluate efficacy and safety. Aliment Pharmacol Ther. 2007;25(11):1351–1361. DOIDose-ranging CIC trial establishing the 24 mcg twice-daily dose; demonstrated increased SBM frequency within 24 hours.
- Drossman DA, Chey WD, Johanson JF, et al. Clinical trial: lubiprostone in patients with constipation-associated irritable bowel syndrome — results of two randomized, placebo-controlled studies. Aliment Pharmacol Ther. 2009;29(3):329–341. DOICombined analysis of two Phase 3 IBS-C trials (N=1171) establishing efficacy of 8 mcg twice daily (17.9% vs 10.1% overall responders).
- Jamal MM, Adams AB, Jansen JP, et al. A randomized, placebo-controlled trial of lubiprostone for opioid-induced constipation in chronic noncancer pain. Am J Gastroenterol. 2015;110(5):725–732. DOIPhase 3 OIC trial demonstrating improved SBM frequency with lubiprostone 24 mcg twice daily in non-methadone opioid users.
- Spierings ELH, Drossman DA, Cryer B, et al. Efficacy and safety of lubiprostone in patients with opioid-induced constipation: Phase 3 study results and pooled analysis of the effect of concomitant methadone use on clinical outcomes. Pain Med. 2018;19(6):1184–1194. DOIPooled Phase 3 OIC analysis confirming efficacy with non-methadone opioids and lack of efficacy with methadone.
- Chey WD, Drossman DA, Johanson JF, et al. Safety and patient outcomes with lubiprostone for up to 52 weeks in patients with irritable bowel syndrome with constipation. Aliment Pharmacol Ther. 2012;35(5):587–599. DOILong-term open-label IBS-C safety study (36 weeks) confirming sustained tolerability and patient-reported outcomes.
- Chang L, Sultan S, Lembo A, et al. AGA Clinical Practice Guideline on the pharmacological management of irritable bowel syndrome with constipation. Gastroenterology. 2022;163(1):118–136. DOIConditional recommendation for lubiprostone in IBS-C (moderate-certainty evidence); ranked below linaclotide (strong recommendation).
- Chang L, Chey WD, Imdad A, et al. AGA–ACG Clinical Practice Guideline: pharmacological management of chronic idiopathic constipation. Gastroenterology. 2023;164(7):1086–1106. DOIConditional recommendation for lubiprostone in CIC (low-certainty evidence); linaclotide, plecanatide, and prucalopride received strong recommendations.
- Lacy BE, Pimentel M, Brenner DM, et al. ACG Clinical Guideline: management of irritable bowel syndrome. Am J Gastroenterol. 2021;116(1):17–44. DOIACG guideline strongly recommending chloride channel activators for IBS-C based on moderate-quality evidence.
- Lacy B, Levy L. Lubiprostone: a chloride channel activator. J Clin Gastroenterol. 2007;41(4):345–351. DOIFoundational review of ClC-2 activation mechanism, intestinal secretion physiology, and preclinical pharmacology.
- Cryer B, Drossman DA, Chey WD, et al. Analysis of nausea in clinical studies of lubiprostone for the treatment of constipation disorders. Dig Dis Sci. 2017;62(12):3568–3578. DOIComprehensive pooled nausea analysis across CIC, OIC, and IBS-C trials characterizing incidence, severity, timing, and impact on treatment continuation.
- Cuppoletti J, Malinowska DH, Tewari KP, et al. SPI-0211 activates T84 cell chloride transport and recombinant human ClC-2 chloride currents. Am J Physiol Cell Physiol. 2004;287(5):C1173–C1183. DOIKey in vitro study demonstrating that lubiprostone (SPI-0211) specifically activates ClC-2 channels in intestinal epithelial cells.