Amitiza

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. ( 1.2 , 7.1 ) irritable bowel syndrome with constipation (IBS-C) in women ≥ 18 years old.

1.1Chronic Idiopathic Constipation in Adults Amitiza

® is indicated for the treatment of chronic idiopathic constipation (CIC) in adults.

1.2Opioid-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.

1.3Irritable 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.

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.

2.1Recommended 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

2.2Administration 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. ( 2.2 , 5.1 ) 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. ( 4 , 5.5 )

5.1Nausea Patients

taking Amitiza may experience nausea. Concomitant administration of food with Amitiza may reduce symptoms of nausea .

5.2Diarrhea 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 .

5.3Syncope 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.

5.4Dyspnea 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.

5.5Bowel 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 .

Amitiza is contraindicated in patients with known or suspected mechanical gastrointestinal obstruction . Patients with known or suspected mechanical gastrointestinal obstruction. ( 4 , 5.5 )

8.1Pregnancy Risk Summary Following

oral administration, concentrations of lubiprostone in plasma are below the level of quantitation; however, one of the metabolites, M3, has measurable systemic concentrations . Limited available data with lubiprostone use in pregnant women are insufficient to inform a drug associated risk of adverse developmental outcomes. Animal reproduction studies did not show an increase in structural malformations . Although a dose dependent increase in fetal loss was observed in pregnant guinea pigs that received lubiprostone (doses equivalent to 0.2 to 6 times the maximum recommended human dose (MRHD) based on body surface area (mg/m 2 )), these effects were probably secondary to maternal toxicity and occurred after the period of organogenesis . The background risk of major birth defects and miscarriage for the indicated population is unknown. All pregnancies have a background risk of birth defect, loss, or other adverse outcomes.

In the U.S. general population, the estimated background risk of major birth defects and miscarriage in clinically recognized pregnancies is 2 to 4% and 15 to 20%, respectively. Data Animal Data In developmental toxicity studies, pregnant rats and rabbits received oral lubiprostone during organogenesis at doses up to approximately 338 times (rats) and approximately 34 times (rabbits) the maximum recommended human dose (MRHD) based on body surface area (mg/m 2 ). Maximal animal doses were 2000 mcg/kg/day (rats) and 100 mcg/kg/day (rabbits).

In rats, there were increased incidences of early resorptions and soft tissue malformations ( situs inversus , cleft palate) at the 2000 mcg/kg/day dose; however, these effects were probably secondary to maternal toxicity. A dose-dependent increase in fetal loss occurred when guinea pigs received lubiprostone after the period of organogenesis, on days 40 to 53 of gestation, at daily oral doses of 1, 10, and 25 mcg/kg/day (approximately 0.2, 2 and 6 times the MRHD based on body surface area (mg/m 2 )); however, these effects were probably secondary to maternal toxicity. The potential of lubiprostone to cause fetal loss was also examined in pregnant rhesus monkeys.

Monkeys received lubiprostone post-organogenesis on gestation days 110 through 130 at daily oral doses of 10 and 30 mcg/kg/day (approximately 3 and 10 times the MRHD based on body surface area (mg/m 2 )). Fetal loss was noted in one monkey from the 10-mcg/kg dose group, which is within normal historical rates for this species. There was no drug-related adverse effect seen in monkeys.

The following adverse reactions are described below and elsewhere in labeling: Nausea Diarrhea Syncope and Hypotension Dyspnea Most common adverse reactions (> 4%) are: CIC: nausea, diarrhea, headache, abdominal pain, abdominal distension, and flatulence. OIC: nausea and diarrhea. IBS-C: nausea, diarrhea, and abdominal pain. To report SUSPECTED ADVERSE REACTIONS, contact Mallinckrodt at 1-800-844-2830 or FDA at 1-800-FDA-1088 or www.fda.gov/medwatch.

6.1Clinical Trials Experience Because

clinical studies are conducted under widely varying conditions, adverse reaction rates observed in the clinical studies of a drug cannot be directly compared to rates in the clinical studies of another drug and may not reflect the rates observed in practice. During clinical development of Amitiza for CIC, OIC, and IBS-C, 1648 patients were treated with Amitiza for 6 months and 710 patients were treated for 1 year (not mutually exclusive). Chronic Idiopathic Constipation Adverse reactions in adult dose-finding, efficacy, and long-term clinical studies: The data described below reflect exposure to Amitiza 24 mcg twice daily in 1113 patients with CIC over 3- or 4-week, 6-month, and 12-month treatment periods; and from 316 patients receiving placebo over short-term exposure (≤4 weeks).

The placebo population (N = 316) had a mean age of 48 (range 21 to 81) years; was 87% female; 81% Caucasian, 10% African American, 7% Hispanic, 1% Asian, and 12% elderly (≥65 years of age). Of those patients treated with Amitiza 24 mcg twice daily (N=1113), the mean age was 50 (range 19-86) years; 87% were female; 86% Caucasian, 8% African American, 5% Hispanic, 1% Asian, and 17% elderly (≥65 years of age). The most common adverse reactions (>4%) in CIC were nausea, diarrhea, headache, abdominal pain, abdominal distension, and flatulence.

Table 2 presents data for the adverse reactions that occurred in at least 1% of patients and that occurred more frequently with Amitiza than placebo. Table 2. Adverse Reactions Reported in at least 1% of patients treated with Amitiza and greater than placebo in Clinical Trials of Adults with CIC System/Adverse Reaction Placebo Amitiza 24 mcg Twice Daily N = 316 % N = 1113 % Nausea 3 29 Diarrhea 1 12 Headache 5 11 Abdominal pain 3 8 Abdominal distension 2 6 Flatulence 2 6 Vomiting 0 3 Loose stools 0 3 Edema <1 3 Abdominal discomfort This term combines "abdominal tenderness," "abdominal rigidity," "gastrointestinal discomfort," "stomach discomfort", and "abdominal discomfort." 1 3 Dizziness 1 3 Chest discomfort/pain 0 2 Dyspnea 0 2 Dyspepsia <1 2 Fatigue 1 2 Dry mouth <1 1 Nausea: Approximately 29% of patients who received Amitiza experienced nausea; 4% of patients had severe nausea and 9% of patients discontinued treatment due to nausea.

The rate of nausea was lower among male (8%) and elderly (19%) patients. No patients in the clinical studies were hospitalized due to nausea. Diarrhea: Approximately 12% of patients who received Amitiza experienced diarrhea; 2% of patients had severe diarrhea and 2% of patients discontinued treatment due to diarrhea.

Electrolytes: No serious adverse reactions of electrolyte imbalance were reported in clinical studies, and no clinically significant changes were seen in serum electrolyte levels in patients receiving Amitiza. Less common adverse reactions (<1%): fecal incontinence, muscle cramp, defecation urgency, frequent bowel movements, hyperhidrosis, pharyngolaryngeal pain, intestinal functional disorder, anxiety, cold sweat, constipation, cough, dysgeusia, eructation, influenza, joint swelling, myalgia, pain, syncope, tremor, decreased appetite. Opioid-Induced Constipation Adverse reactions in adult efficacy and long-term clinical studies: The data described below reflect exposure to Amitiza 24 mcg twice daily in 860 patients with OIC for up to 12 months and from 632 patients receiving placebo twice daily for up to 12 weeks.

The total population (N = 1492) had a mean age of 50 (range 20–89) years; was 63% female; 83% Caucasian, 14% African American, 1% American Indian/Alaska Native, 1% Asian; 5% were of Hispanic ethnicity, and 9% were elderly (≥65 years of age). The most common adverse reactions (>4%) in OIC were nausea and diarrhea. Table 3 presents data for the adverse reactions that occurred in at least 1% of patients and that occurred more frequently with study drug than placebo.

Table 3. Adverse Reactions Reported in at least 1% of patients treated with Amitiza and greater than placebo in Clinical Trials of Adults with OIC System/Adverse Reaction Placebo Amitiza 24 mcg Twice Daily N = 632 % N = 860 % Nausea 5 11 Diarrhea 2 8 Abdominal pain 1 4 Flatulence 3 4 Abdominal distension 2 3 Vomiting 2 3 Headache 1 2 Peripheral edema <1 1 Abdominal discomfort This term combines "abdominal tenderness," "abdominal rigidity," "gastrointestinal discomfort," "stomach discomfort", and "abdominal discomfort." 1 1 Nausea: Approximately 11% of patients who received Amitiza experienced nausea; 1% of patients had severe nausea and 2% of patients discontinued treatment due to nausea. Diarrhea: Approximately 8% of patients who received Amitiza experienced diarrhea; 2% of patients had severe diarrhea and 1% of patients discontinued treatment due to diarrhea.

Less common adverse reactions (<1%): fecal incontinence, blood potassium decreased. Irritable Bowel Syndrome with Constipation Adverse reactions in adult dose-finding, efficacy, and long-term clinical studies: The data described below reflect exposure to Amitiza 8 mcg twice daily in 1011 patients with IBS-C for up to 12 months and from 435 patients receiving placebo twice daily for up to 16 weeks. The total population (N = 1267) had a mean age of 47 (range 18–85) years; was 92% female; 78% Caucasian, 13% African American, 9% Hispanic, 0.4% Asian, and 8% elderly (≥65 years of age).

The most common adverse reactions (>4%) in IBS-C were nausea, diarrhea, and abdominal pain. Table 4 presents data for the adverse reactions that occurred in at least 1% of patients and that occurred more frequently with study drug than placebo. Table 4. Adverse Reactions Reported in at least 1% of patients treated with Amitiza and greater than placebo in Clinical Trials of Adults with IBS-C System/Adverse Reaction Placebo Amitiza 8 mcg Twice Daily N = 435 % N = 1011 % Nausea 4 8 Diarrhea 4 7 Abdominal pain 5 5 Abdominal distension 2 3 Nausea: Approximately 8% of patients who received Amitiza 8 mcg twice daily experienced nausea; 1% of patients had severe nausea and 1% of patients discontinued treatment due to nausea.

Diarrhea: Approximately 7% of patients who received Amitiza 8 mcg twice daily experienced diarrhea; <1% of patients had severe diarrhea and <1% of patients discontinued treatment due to diarrhea. Less common adverse reactions (<1%): dyspepsia, loose stools, vomiting, fatigue, dry mouth, edema, increased alanine aminotransferase, increased aspartate aminotransferase, constipation, eructation, gastroesophageal reflux disease, dyspnea, erythema, gastritis, increased weight, palpitations, urinary tract infection, anorexia, anxiety, depression, fecal incontinence, fibromyalgia, hard feces, lethargy, rectal hemorrhage, pollakiuria.

6.2Postmarketing Experience The

following additional adverse reactions have been identified during post-approval use of Amitiza. Because these reactions are reported voluntarily from a population of uncertain size, it is not always possible to reliably estimate their frequency or establish a causal relationship to drug exposure. Cardiovascular: syncope and/or hypotension , tachycardia Gastrointestinal: ischemic colitis General: asthenia Immune System: hypersensitivity reactions including rash, swelling, and throat tightness malaise Muscoskeletal: muscle cramps or muscle spasms.