General MedicinePrescription OnlyPregnancy Cat. Not classifiedFDA Yes

Synarel

NAFARELIN ACETATE

INDICATIONS AND USAGE FOR CENTRAL PRECOCIOUS PUBERTY (For Endometriosis, See Reverse Side ) SYNAREL is indicated for treatment of central precocious puberty (CPP) (gonadotropin-dependent precocious puberty) in children of both sexes. The diagnosis of central precocious puberty (CPP) is suspected when premature development of secondary sexual characteristics occurs at or before the age of 8 years in girls and 9 years in boys, and is accompanied by significant advancement of bone age and/or a poor...

Medically reviewed by MedCentralHub Medical Review Board, Licensed Pharmacists & Physicians · May 2026

Brand names:Synarel

Rx Only

SynarelMedication

Quick Reference

Medicine ClassGeneral Medicine

FDA ApprovedYes

PregnancyCategory Not classified

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Quick Facts

Active ingredient: NAFARELIN ACETATE
Medicine class: General Medicine
Brand names: Synarel
Availability: Prescription only (Rx)
Pregnancy category: Not classified
FDA approved: Yes

Synarel (NAFARELIN ACETATE) medication overview

What Is Synarel?

Synarel (NAFARELIN ACETATE) belongs to the General Medicine class of medications. It was first approved by the FDA in Yes. This medication requires a prescription from a licensed healthcare provider.

Key Safety Information

•Always follow the dose recommended by your healthcare professional. Taking more than prescribed increases the risk of side effects including serious complications.
•Seek emergency care if you experience signs of an allergic reaction — hives, swelling, difficulty breathing, or rash. Stop the medication and call your doctor immediately.
•Some medications can increase the risk of cardiovascular events. Tell your doctor if you have high blood pressure, a history of heart attack or stroke, or any pre-existing health condition.
•Avoid or limit alcohol while taking Synarel. Do not drink alcohol without first discussing it with your healthcare provider as it may increase adverse effects.
•Take Synarel with food or a full glass of water if stomach upset occurs. Stop use and talk to your doctor if you experience persistent stomach pain or GI symptoms.
•Tell your doctor about all medications, supplements, and vitamins you take. Some combinations significantly increase the risk of harm.

This is a summary only. Always read the full prescribing information and consult your healthcare provider for personalized medical advice.

Uses & Indications

Synarel is prescribed for the following conditions. Some uses are FDA-approved indications; others may be evidence-based off-label uses. Consult your healthcare provider for personalized guidance.

The diagnosis of central precocious puberty (CPP) is suspected when premature development of secondary sexual characteristics occurs at or before the age of 8 years in girls and 9 years in boys, and is accompanied by significant advancement of bone age and/or a poor adult height prediction.

The diagnosis should be confirmed by pubertal gonadal sex steroid levels and a pubertal LH response to stimulation by native GnRH.

Pelvic ultrasound assessment in girls usually reveals enlarged uterus and ovaries, the latter often with multiple cystic formations.

Magnetic resonance imaging or CT-scanning of the brain is recommended to detect hypothalamic or pituitary tumors, or anatomical changes associated with increased intracranial pressure.

Other causes of sexual precocity, such as congenital adrenal hyperplasia, testotoxicosis, testicular tumors and/or other autonomous feminizing or masculinizing disorders must be excluded by proper clinical hormonal and diagnostic imaging examinations.

Dosage Guide

The following are general dosing guidelines only. Your actual dose should be determined by your healthcare provider based on your condition, renal/hepatic function, and other medications.

Adult Dosage

DOSAGE AND ADMINISTRATION For the treatment of central precocious puberty (CPP), the recommended daily dose of SYNAREL is 1600 µg. The dose can be increased to 1800 µg daily if adequate suppression cannot be achieved at 1600 µg/day. The 1600 µg dose is achieved by two sprays (400 µg) into each nostril in the morning (4 sprays) and two sprays into each nostril in the evening (4 sprays), a total of 8 sprays per day. The 1800 µg dose is achieved by 3 sprays (600 µg) into alternating nostrils three times a day, a total of 9 sprays per day. The patient's head should be tilted back slightly, and 30 seconds should elapse between sprays. If the prescribed therapy has been well tolerated by the patient, treatment of CPP with SYNAREL should continue until resumption of puberty is desired. There appeared to be no significant effect of rhinitis, i.e., nasal congestion, on the systemic bioavailability of SYNAREL; however, if the use of a nasal decongestant for rhinitis is necessary during treatment

Available Forms

Available Strengths

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Side Effects

Common

ADVERSE REACTIONS In clinical trials of 155 pediatric patients, 2.6% reported symptoms suggestive of drug sensitivity, such as shortness of breath, chest pain, urticaria, rash, and pruritus.
In these 155 patients treated for an average of 41 months and as long as 80 months (6.7 years), adverse events most frequently reported (>3% of patients) consisted largely of episodes occurring during the first 6 weeks of treatment as a result of the transient stimulatory action of nafarelin upon the pituitary-gonadal axis: acne (10%) transient breast enlargement (8%) vaginal bleeding (8%) emotional lability (6%) [see Warnings ] transient increase in pubic hair (5%) body odor (4%) seborrhea (3%) Hot flashes, common in adult women treated for endometriosis, occurred in only 3% of treated children and were transient.
Other adverse events thought to be drug-related, and occurring in >3% of patients were rhinitis (5%) and white or brownish vaginal discharge (3%).
Approximately 3% of patients withdrew from clinical trials due to adverse events.
In one male patient with concomitant congenital adrenal hyperplasia, and who had discontinued treatment 8 months previously to resume puberty, adrenal rest tumors were found in the left testis.
Relationship to SYNAREL is unlikely.
Regular examinations of the pituitary gland by magnetic resonance imaging (MRI) or computer assisted tomography (CT) of children during long-term nafarelin therapy as well as during the post-treatment period has occasionally revealed changes in the shape and size of the pituitary gland.

Serious

WARNINGS The diagnosis of central precocious puberty (CPP) must be established before treatment is initiated.
Regular monitoring of CPP patients is needed to assess both patient response as well as compliance.
This is particularly important during the first 6 to 8 weeks of treatment to assure that suppression of pituitary-gonadal function is rapid.
Testing may include LH response to GnRH stimulation and circulating gonadal sex steroid levels.
Assessment of growth velocity and bone age velocity should begin within 3 to 6 months of treatment initiation.

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Medicine Interactions

Always inform your healthcare provider and pharmacist about ALL medications you take, including prescriptions, OTC medicines, vitamins, and supplements.

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Warnings & Contraindications

WARNINGS The diagnosis of central precocious puberty (CPP) must be established before treatment is initiated. Regular monitoring of CPP patients is needed to assess both patient response as well as compliance. This is particularly important during the first 6 to 8 weeks of treatment to assure that suppression of pituitary-gonadal function is rapid. Testing may include LH response to GnRH stimulati

WARNINGS Safe use of nafarelin acetate in pregnancy has not been established clinically. Before starting treatment with SYNAREL, pregnancy must be excluded. When used regularly at the recommended dose, SYNAREL usually inhibits ovulation and stops menstruation. Contraception is not insured, however, by taking SYNAREL, particularly if patients miss successive doses. Therefore, patients should use no

How Synarel Works

Pharmacokinetics

Pregnancy & Breastfeeding Safety

Not classified

FDA Pregnancy Category Not classified

Consult your healthcare provider.

Full Pregnancy Information

Breastfeeding

Many medications pass into breast milk in varying amounts. Before using Synarelwhile breastfeeding, discuss the benefits and risks with your healthcare provider or pharmacist — they can weigh your dose, your infant's age, and available lactation safety data to find the safest option for you and your baby.

Storage & Handling

Store upright at 25°C (77°F); excursions permitted to 15–30°C (59–86°F) [see USP Controlled Room Temperature]. Protect from light.

Frequently Asked Questions

Sources & References

• FDA Prescribing Information — Official labeling and package insert for Synarel
• U.S. National Library of Medicine — MedlinePlus drug information
• American Hospital Formulary Service (AHFS) — Clinical pharmacology monograph
• PubMed / MEDLINE — View clinical studies

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Medical Disclaimer

The information on this page is for educational purposes only and is not intended as medical advice, diagnosis, or treatment. Always consult your doctor, pharmacist, or qualified healthcare provider before starting, stopping, or changing any medication.