Experience with the Histrelin Implant in Pediatric Patients.

The histrelin implant has emerged as a therapeutic option for the treatment of central precocious puberty that has been favorably received by patients and providers. Inserted subcutaneously, the 50-mg implant provides continuous release of the potent gonadotropin-releasing hormone analog (GnRHa) histrelin. Profound suppression of the hypothalamic-pituitary-gonadal (HPG) axis occurs within 1 month of its placement resulting in pubertal arrest, attenuation of skeletal advancement and a progressive increase in predicted adult height. Although marketed for annual use, suppression lasting 2 years from a single implant has been demonstrated. Placing and removing the device is a minor outpatient procedure easily accomplished by a pediatric surgeon using local anesthesia. The major downside to the implant is a ∼25% rate of breakage upon removal. Information about the recovery of the HPG axis following histrelin explantation is limited but suggests an average time to menarche comparable with depot GnRHa formulations albeit with wide individual variation.