Triptorelin injection (Trelstar) is used to treat the symptoms associated with advanced prostate cancer. Triptorelin injection (Triptodur) is used to treat central precocious puberty (CPP; a condition causing children to enter puberty too soon, resulting in faster than normal bone growth and development of sexual characteristics) in children 2 years and older. Triptorelin injection is in a class of medications called gonadotropin-releasing hormone (GnRH) agonists.