Naltrexone is an opiate antagonist binding to μ-opiate receptors. It was FDA approved for opiate addiction in 1984 and for alcohol in 1994. Vivitrol injections of extended release Naltrexone lasts about one month and was approved in 2006.
Although the active ingredient, Naltrexone, has been FDA approved since 1984, its delivery in the form of an implant has not. However, this extended release implant is compounded by a licensed pharmacy under strict quality control and sterilization standards and has been available for over 15 years. It typically remains in the subcutaneous tissue of the left or right abdominal quadrant for 3 – 6 months, then biodegrades and is dissolved. Depending on pellet design and the patient’s metabolism, Naltrexone blood levels remain therapeutic during this time period.