Nafarelin: uses, dosing, side effects & brands
Nafarelin is a medicine sold in the U.S. under one brand, for endometriosis and precocious puberty. Below: what the FDA label says, every product that contains it, what the pills look like, and its recall record.
Key facts
- Treats
- Endometriosis and Precocious Puberty
- Available as
- Spray/Inhaler, metered
- Sold as
- Synarel
- Prescription?
- Prescription only
- Generic available?
- Not in our catalog
How nafarelin is dosed
From the FDA label for Synarel (application NDA019886). Other nafarelin products — different forms, different strengths — are dosed differently. Follow the label for the one you were prescribed.
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 with SYNAREL, the decongestant should not be used until at least 2 hours following dosing with SYNAREL. Sneezing during or immediately after dosing with SYNAREL should be avoided, if possible, since this may impair drug absorption. At 1600 µg/day, a bottle of SYNAREL provides about a 7-day supply (about 56 sprays). If the daily dose is increased, increase the supply to the patient to ensure uninterrupted treatment for…
Nafarelin side effects
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…
Who shouldn’t take nafarelin
1. Hypersensitivity to GnRH, GnRH agonist analogs or any of the excipients in SYNAREL; 2. Undiagnosed abnormal vaginal bleeding; 3. Use in pregnancy or in women who may become pregnant while receiving the drug. SYNAREL may cause fetal harm when administered to a pregnant woman. Major fetal abnormalities were observed in rats, but not in mice or rabbits after administration of SYNAREL during the period of organogenesis. There was a dose-related increase in fetal mortality and a decrease in fetal weight in rats [see Pregnancy ] . The effects on rat fetal mortality are expected consequences of the alterations in hormonal levels brought about by the drug. If this drug is used during pregnancy or if the patient becomes pregnant while taking this drug, she should be apprised of the potential hazard to the fetus; 4. Use in women who are breast-feeding [see Nursing Mothers ] . CONTRAINDICATIONS 1. Hypersensitivity to GnRH, GnRH agonist analogs or any of the excipients in SYNAREL; 2. Undiagnosed abnormal vaginal bleeding; 3. Use in pregnancy or in women who may become pregnant while receiving the drug. SYNAREL may cause fetal harm when administered to a pregnant woman. Major fetal abnormalities were observed in rats, but not in mice or rabbits after administration of SYNAREL during the period of organogenesis. There was a dose-related increase in fetal mortality and a decrease in fetal weight in rats [see Pregnancy ] . The effects on rat fetal mortality are expected consequences of the alterations in hormonal levels brought about by the drug. If this drug is used during pregnancy or if the patient becomes pregnant while taking this drug, she should be apprised of the potential hazard to the fetus; 4. Use in women who are breast-feeding [see Nursing Mothers ] .
Nafarelin drug interactions
No pharmacokinetic-based drug-drug interaction studies have been conducted with SYNAREL. However, because nafarelin acetate is a peptide that is primarily degraded by peptidase and not by cytochrome P-450 enzymes, and the drug is only about 80% bound to plasma proteins at 4°C, drug interactions would not be expected to occur. Drug Interactions No pharmacokinetic-based drug-drug interaction studies have been conducted with SYNAREL. However, because nafarelin acetate is a peptide that is primarily degraded by peptidase and not by cytochrome P-450 enzymes, and the drug is only about 80% bound to plasma proteins at 4°C, drug interactions would not be expected to occur.
Every nafarelin product we track (1)
Same active ingredient — different manufacturer, form, price and FDA recall record. That last one is what our independent score measures.
Only one: Synarel.
What people report to the FDA about nafarelin
The FDA Adverse Event Reporting System (FAERS) collects reports from patients and clinicians. It holds 76 reports naming nafarelin, and the FDA flagged 97% of those reports as serious. The effects reported most often — leaving out reports about overdose, misuse or the condition being treated, which dominate the raw list for common medicines:
- ovarian hyperstimulation syndrome10 reports
- diarrhoea8 reports
- dysgeusia8 reports
- muscle twitching8 reports
- abdominal pain lower5 reports
- abdominal discomfort4 reports
- ascites4 reports
- dyspnoea4 reports
Read these as a signal, not a rate. A report does not mean nafarelin caused the effect — anyone can file one, and many describe people taking several medicines for several conditions. Crucially there is no denominator: FAERS does not record how many people took the drug, so these counts cannot be turned into “X% of patients” — a bigger number often just means a more widely used or more talked-about drug. Duplicates exist, and publicity drives reporting. For what is actually established, read the FDA label section above.
Source: openFDA drug/event (FAERS), retrieved July 25, 2026.
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Frequently asked questions
What is nafarelin?
SYNAREL (nafarelin acetate) Nasal Solution is intended for administration as a spray to the nasal mucosa.
Can you take nafarelin with other medicines?
It depends on the medicine. We check it against the FDA labels rather than guessing: our interaction checker searches each drug's own label for the other and quotes what it says, naming the section it came from. Run nafarelin against whatever else you take — and remember that a label not naming a drug is not the same as that combination being safe.
What forms does nafarelin come in?
Across the brands we track, nafarelin is currently marketed as spray/inhaler, metered, per the FDA's National Drug Code Directory. Each form is dosed differently — follow the label for the exact product you were prescribed.
Is there a generic nafarelin?
We do not currently list a generic-labelled nafarelin product. That does not always mean none exists — it means none appears under a generic name in the FDA data we track. Ask your pharmacist.
Cite this page
- APA
- pharmaranks. (2026, July 24). Nafarelin: uses, dosing, side effects & brands. https://pharmaranks.com/drugs/nafarelin
- MLA
- “Nafarelin: uses, dosing, side effects & brands.” pharmaranks, 24 July 2026, https://pharmaranks.com/drugs/nafarelin.
We summarise public FDA and NIH sources — for a clinical claim, cite the primary source we link to as well.
Sources: FDA openFDA drug label, National Drug Code Directory, and Enforcement (recall) database. This page reproduces public FDA data and is not medical advice. Dosing is set by your prescriber.
Read the full FDA label for nafarelin on DailyMed (NIH) ↗.