This study will evaluate the effect of various degrees of hepatic function on the pharmacokinetics and safety of ALKS 5461.

Inclusion Criteria:

For all subjects:

• Has a body mass index (BMI) of 18.0-35.0 kg/m2 and a total body weight >50 kg
• Agrees to use an approved method of contraception for the duration of the study
• Additional criteria may apply

For subjects with hepatic impairment:

• Has mild, moderate, or severe hepatic impairment
• Has hepatic dysfunction due to hepatocellular disease
• Additional criteria may apply

Exclusion Criteria:

For all subjects:

• Has any past history or current finding of a clinically significant observed abnormality, psychiatric or medical condition other than hepatic impairment
• Has a history of gastrointestinal surgery, excluding appendectomy or cholecystectomy
• Is pregnant, planning to become pregnant, or lactating
• Has a history of clinically significant allergy or a hypersensitivity to opioids
• Additional criteria may apply

For subjects with hepatic impairment:

• Has evidence of hepatocellular carcinoma, acute liver disease, biliary obstruction, severe ascites, severe portal hypertension, surgical systemic shunts, or other clinically relevant liver-related disorder or condition
• Has received a liver transplant
• Has had esophageal variceal bleeding in the past 2 months
• Additional criteria may apply