Depression, suicide, and suicidality
Vulnerability to opioid overdose: Patients should be alerted that they may be more sensitive to opioids, even at lower doses, after discontinuance of<unk> 
Hepatotoxicity
Severe injection-site reactions (e.g. necrosis, cellulitis, hematoma)

Injection site reaction
Nausea/vomiting, diarrhea, decreased appetite, dry mouth
LFT abnormalities,
Elevated CPK
Headache, dizziness, anxiety, insomnia, somnolence
URI, pharyngitis
Arthralgia, muscle cramps, back pain
Rash
Naltrexone
Methadone
Buprenorphine
Hydrocodone
Nortriptyline
Promethazine
Duloxetine
Oxazepam