According to WebMD, Implanon is gradually being replaced by the very similar contraceptive implant, Nexplanon. Both implants are a small plastic rod the size of a matchstick that releases the hormone etonogestrel (a form of progesterone).
The biggest difference between the two contraceptive implants is that Nexplanon has barium in the rod so the location can be found via X-ray.
WebMD mentioned that the maker of Implanon and Nexplanon stopped distributing Implanon in December of 2012 to phase it out.
