50 mg/day oral; 380 mg/4 weeks IM (Vivitrol); 32 mg + 360 mg naltrexone/bupropion daily (Contrave maximum after titration)
pill_id
Text
routes
List of String, delimiter: ,
Oral • intramuscular (depot)
onset
String
Oral peak plasma 1 hour; therapeutic opioid blockade within hours of first dose. IM Vivitrol: peak plasma 2-3 days; therapeutic blockade through the dosing interval.
duration
String
Oral mu-blockade clinically meaningful for 24-72 hours; IM Vivitrol blockade through 4 weeks.
halflife
String
Naltrexone parent ~4 hours (oral); 6-beta-naltrexol (active metabolite) ~13 hours. Vivitrol depot terminal half-life 5-10 days with sustained release from microspheres maintaining blockade for the 4-week dosing interval.'"`UNIQ--ref-0000004F-QINU`"'
bioavailability
String
~5-40% (oral, highly variable due to extensive first-pass metabolism; mean ~5-10% for parent naltrexone with the majority of pharmacologic effect coming from 6-beta-naltrexol). IM Vivitrol bypasses first-pass entirely.'"`UNIQ--ref-00000050-QINU`"'
