Parents navigating an early puberty diagnosis, or patients exploring hormone-based fertility support, often want to understand what a drug like nafarelin actually does before starting it. Nafarelin is a synthetic peptide marketed under an approved label, with a defined set of indications and a known pattern of reported reactions.
Key takeaways
- Nafarelin is approved under the brand name Synarel for central precocious puberty.
- It carries no boxed warning on its label.
- Ovarian hyperstimulation syndrome is the most frequently reported reaction in safety data.
- At least 13 clinical trials have studied nafarelin or related protocols, including IVF-focused research.
- The compound has a molecular weight of about 1,322.5 and the formula C66H83N17O13.
What Nafarelin Is
Nafarelin is a peptide compound identified in PubChem under CID 25077405. Its approved label does not detail a specific mechanism-of-action statement, but it is formulated and marketed as the brand Synarel.
What Nafarelin Is Approved For
Synarel is indicated for central precocious puberty (CPP), also called gonadotropin-dependent precocious puberty, in both girls and boys. This diagnosis is typically considered when secondary sexual characteristics appear before age 8 in girls or age 9 in boys, alongside advanced bone age or a reduced predicted adult height. Confirmation relies on pubertal gonadal sex steroid levels, a pubertal LH response to GnRH stimulation, and pelvic ultrasound findings such as enlarged uterus and ovaries, sometimes with cystic changes. The label notes that Synarel is also used for endometriosis, though full endometriosis labeling detail was not provided here. Nafarelin's label does not carry a boxed warning.
What the Evidence Shows
Nafarelin and related treatment protocols have been studied across at least 13 registered clinical trials. Among the sampled studies, a Phase 3 trial is recruiting participants to evaluate luteal phase support with a GnRH agonist after GnRH agonist triggering in IVF and ICSI cycles. A completed Phase 4 trial compared short versus long treatment protocols for IVF, with or without ICSI, reflecting how nafarelin-based regimens are studied in fertility settings.
Reported Side Effects
Reported safety data for nafarelin is dominated by ovarian hyperstimulation syndrome, with 48 reports, making it the most commonly flagged reaction. Respiratory and abdominal findings follow, including dyspnoea (19 reports) and ascites (18 reports), both of which can accompany hyperstimulation. Other reported reactions include condition aggravated, diarrhoea, headache, and nausea, each with 13 reports, alongside 13 reports classified as off-label use. These figures reflect spontaneous report counts submitted to a safety surveillance system, not confirmed incidence rates or proof that nafarelin caused the event.