Amitiza (lubiprostone) is a chloride channel activator for oral use. The chemical name for lubiprostone is (–)-7-[(2 R ,4a R ,5 R ,7a R )-2-(1,1-difluoropentyl)-2-hydroxy-6-oxooctahydrocyclopenta[ b ]pyran-5-yl]heptanoic acid. The molecular formula of lubiprostone is C 20 H 32 F 2 O 5 with a molecular weight of 390.46 and a chemical structure as follows: Lubiprostone drug substance occurs as white, odorless crystals or crystalline powder, is very soluble in ether and ethanol, and is practically insoluble in hexane and water. Amitiza is available as an imprinted, oval, soft gelatin capsule in two strengths. Pink capsules contain 8 mcg of lubiprostone and the following inactive ingredients: ferric oxide, gelatin, medium-chain triglycerides, purified water, sorbitol, and titanium dioxide. Orange capsules contain 24 mcg of lubiprostone and the following inactive ingredients: D&C Yellow #10, FD&C Red #40, gelatin, medium-chain triglycerides, purified water, and sorbitol. Chemical Structure

Amitiza is a chloride channel activator indicated for the treatment of: chronic idiopathic constipation (CIC) in adults. opioid-induced constipation (OIC) in adult patients with chronic, non-cancer pain, including patients with chronic pain related to prior cancer or its treatment who do not require frequent (e.g., weekly) opioid dosage escalation. Limitations of Use: Effectiveness of Amitiza in the treatment of OIC in patients taking diphenylheptane opioids (e.g., methadone) has not been established. irritable bowel syndrome with constipation (IBS-C) in women ≥ 18 years old

Chronic Idiopathic Constipation in Adults Amitiza ® is indicated for the treatment of chronic idiopathic constipation (CIC) in adults

Opioid-Induced Constipation in Adult Patients with Chronic Non-Cancer Pain Amitiza is indicated for the treatment of opioid-induced constipation (OIC) in adult patients with chronic non-cancer pain, including patients with chronic pain related to prior cancer or its treatment who do not require frequent (e.g., weekly) opioid dosage escalation. Limitations of Use: Effectiveness of Amitiza in the treatment of opioid-induced constipation in patients taking diphenylheptane opioids (e.g., methadone) has not been established. 1.3 Irritable Bowel Syndrome with Constipation Amitiza is indicated for the treatment of irritable bowel syndrome with constipation (IBS-C) in women at least 18 years old.

Amitiza is available as an oval, gelatin capsule containing 8 mcg or 24 mcg of lubiprostone. 8 mcg capsules are pink and are printed with "SPI" on one side 24 mcg capsules are orange and are printed with "SPI" on one side Capsules: 8 mcg and 24 mcg

Recommended Dosage CIC and OIC: 24 mcg twice daily. IBS-C: 8 mcg twice daily. See full prescribing information for dosage adjustment by indication and degree of hepatic impairment. Administration Instructions Swallow capsules whole and do not break apart or chew, Take capsules with food and water, Assess periodically the need for continuous therapy

Recommended Dosage The recommended oral dosage of Amitiza by indication and adjustments for patients with moderate (Child Pugh Class B) and severe (Child Pugh Class C) hepatic impairment are shown in Table 1. Table 1. Recommended Dosage Regimen CIC and OIC IBS-C Recommended Adult Dosage Regimen 24 mcg twice daily 8 mcg twice daily Dosage Adjustment for Hepatic Impairment Moderate Impairment (Child-Pugh Class B) : 16 mcg twice daily If the dose is tolerated and an adequate response has not been obtained after an appropriate interval, doses can then be escalated to full dosing with appropriate monitoring of patient response. Moderate Impairment (Child-Pugh Class B) : No adjustment necessary Severe Impairment (Child-Pugh Class C) : 8 mcg twice daily Severe Impairment (Child-Pugh Class C) : 8 mcg once daily 2.2 Administration Instructions Take Amitiza orally with food and water. Swallow capsules whole and do not break apart or chew. Physicians and patients should periodically assess the need for continued therapy.

Nausea : Patients may experience nausea; concomitant administration of food may reduce this symptom. Diarrhea : Avoid use in patients with severe diarrhea. Instruct patients to discontinue Amitiza and contact their healthcare provider if severe diarrhea occurs during treatment. Syncope and Hypotension : May occur after taking the first dose or with subsequent doses. Generally resolves prior to the next dose, but may recur with repeat dosing. Instruct patients to discontinue Amitiza and contact their healthcare provider if symptoms occur. Dyspnea : May occur within an hour of first dose. Generally resolves within 3 hours, but may recur with repeat dosing. Instruct patients to contact their healthcare provider if symptoms occur. Bowel Obstruction : Evaluate patients with symptoms suggestive of mechanical gastrointestinal obstruction prior to initiating treatment with Amitiza. 5.1 Nausea Patients taking Amitiza may experience nausea. Concomitant administration of food with Amitiza may reduce symptoms of nausea [ see Adverse Reactions ]

Diarrhea Avoid use of Amitiza in patients with severe diarrhea. Patients should be aware of the possible occurrence of diarrhea during treatment. Instruct patients to discontinue Amitiza and contact their healthcare provider if severe diarrhea occurs [ see Adverse Reactions ]

Syncope and Hypotension Syncope and hypotension have been reported with Amitiza in the postmarketing setting and a few of these adverse reactions resulted in hospitalization. Most cases occurred in patients taking 24 mcg twice daily and some occurred within an hour after taking the first dose or subsequent doses of Amitiza. Some patients had concomitant diarrhea or vomiting prior to developing the adverse reaction. Syncope and hypotension generally resolved following Amitiza discontinuation or prior to next dose, but recurrence has been reported with subsequent doses. Several cases reported concomitant use of medications known to lower blood pressure, which may increase the risk for the development of syncope or hypotension. Patients should be aware of the risk of syncope and hypotension during treatment and that other adverse reactions may increase this risk, such as diarrhea or vomiting

Dyspnea In clinical trials, dyspnea was reported by 3%, 1%, and < 1% of the treated CIC, OIC, and IBS-C populations receiving Amitiza, respectively, compared to 0%, 1%, and < 1% of placebo-treated patients. There have been postmarketing reports of dyspnea when using Amitiza 24 mcg twice daily. Some patients have discontinued treatment because of dyspnea. These events have usually been described as a sensation of chest tightness and difficulty taking in a breath, and generally have an acute onset within 30 to 60 minutes after taking the first dose. They generally resolve within a few hours after taking the dose, but recurrence has been frequently reported with subsequent doses. Instruct patients to contact their healthcare provider if dyspnea occurs

Bowel Obstruction In patients with symptoms suggestive of mechanical gastrointestinal obstruction, perform a thorough evaluation to confirm the absence of an obstruction prior to initiating therapy with Amitiza .

7.1 Methadone Diphenylheptane opioids (e.g., methadone) have been shown in nonclinical studies to dose-dependently reduce the activation of ClC-2 by lubiprostone in the gastrointestinal tract. There is a possibility of a dose-dependent decrease in the efficacy of Amitiza in patients using diphenylheptane opioids. No in vivo interaction studies have been conducted. The effectiveness of Amitiza in the treatment of OIC in patients taking diphenylhepatane opioids (e.g., methadone) has not been established .