The Use Of Synarel In IVF: Costs And Side Effects

By (embryologist), (embryologist), (embryologist) and (invitra staff).
Last Update: 01/21/2020

Synarel is a hormone medication used both in assisted reproduction and to relieve the symptoms of endometriosis.

Specifically, Synarel is used during the controlled ovarian stimulation phase in artificial insemination (AI) and in vitro fertilization (IVF) treatments.

The main advantage of Synarel over other hormonal drugs is that it is a nasal inhaler, i.e. it is not administered as an injection.

Provided below is an index with the 10 points we are going to expand on in this article.

Composition and Mechanism of action

The active ingredient of Synarel is Nafarelin, a gonadotropin-releasing hormone (GnRH) agonist. The remaining excipients are sorbitol, glacial acetic acid, purified water and benzalkonium chloride.

GnRH is a hormone naturally produced by the hypothalamus (brain gland) that stimulates the pituitary gland to produce FSH and LH, hormones that control a woman's ovarian cycle.

The function of Synarel is to act on the pituitary gland by decreasing the normal response to GnRH, so that the endogenous production of FSH and LH is inhibited and, therefore, the ovaries are kept at rest, without estrogen production or follicular development.

In assisted reproduction, this slowing down of the pituitary gland and the ovaries is necessary in order to start ovarian stimulation in a synchronised manner, so that all the follicles develop at the same time and several oocytes are obtained for fertilization.

Package and price of Synarel

Synarel is the only drug used in the process of ovarian stimulation that is administered by nasal solution, making it the ideal choice for women who are afraid of needles or have problems giving themselves an injection.

Synarel comes in a single bottle containing 8 ml of the drug for nasal spraying in 200 microgram doses.

In terms of price, Synarel costs $2,971.80 for a supply of 8 milliliters. In order to purchase Synarel, a doctor’s prescription is necessary.


As we have already mentioned, there are two main indications for the use of Synarel:

  • Controlled ovarian stimulation to seek pregnancy through AI or IVF.
  • Treatment of endometriosis and its associated symptoms

In the latter case of patients suffering from endometriosis, Synarel is able to relieve the symptoms of painful menstruation, painful intercourse and general pelvic pain, as well as reduce significant blood loss during the period.

How is Synarel used?

Before starting to use Synarel, it is important to pay attention to the instructions given by the specialist, especially with regard to the days of administration and dosage.

In the ovarian stimulation process, Synarel is used in the so-called long protocolsbecause it must be administered for several days.

Specifically, its administration starts around day 20 of the previous cycle. Once menstruation has set in, the woman should continue with Synarel inhalations at the same time as she starts the stimulation shots.

As for the dosage of Synarel, we will now give some general recommendations that can serve most patients:

  • The recommended daily dose for assisted reproduction treatments is 4 sprays per day (800 micrograms). This involves spraying both nostrils in the morning and one at night.
  • This dose can be adjusted by the doctor according to the ovarian response, so it is important to perform all medical checks.
  • The recommended daily dose for assisted reproduction treatments is 2 sprays per day (400 micrograms). One administration should be done in the morning, in one nostril, and the second administration in the evening, in the other nostril.
  • If the patient sneezes, during or after the administration of Synarel, it is advisable to repeat the spraying, as it may affect the absorption of the drug.
  • If you miss a dose of Synarel, it is recommended that you administer it as soon as possible. The following sprays should be administered in the usual way and not be compensated if you have forgotten to take a dosis.

As we have said, the doctor can adjust these guidelines according to the patient and the specific treatment.

How to spray

In order to be able to administer Synarel, the sprayer pump must be charged before the first administration. The instructions for this are listed below:

  1. Remove the cap and safety lock.
  2. Place 2 fingers on the valve lugs and your thumb on the base of the bottle.
  3. Pulling the end of the sprayer away, press firmly until a light spray appears.

It should be noted that the first spraying usually occurs after pressing about 5-7 times. Once the medication is prepared, the steps for each application of Synarel are as follows:

  1. Use a tissue to gently wipe both nostrils.
  2. Tilt your head slightly forward, insert the sprayer into one nostril and cover the other nostril with your finger.
  3. Press the sprayer and breathe in at the same time.
  4. Remove the spray from the nose and tilt the head back so that the liquid flows to the back.
  5. Repeat the same operation with the other nostril.

After each use, it is necessary to clean the spray nozzle with warm water while rubbing it with a clean cloth. This can be done by placing the bottle horizontally under the tap.


There are some situations where the use of Synarel is not indicated:

  • Allergy to nafarelin, natural GnRH or any of the other components of Synarel
  • Women with vaginal bleeding of unknown cause
  • Suspected pregnancy
  • Breastfeeding women
  • When Synarel has been used for more than 6 months

On the other hand, in women with a history of ovarian cysts, it is necessary to inform the doctor in order to assess whether or not to administer Synarel, since there may be an increase in the size and number of cysts.

Side effects of Synarel

Like all medications, the administration of Synarel can have side effects that are classified according as to how often they occur.

Very frequent adverse effects

The most frequent symptoms of Synarel are those that appear in 1 out of 10 patients and are as follows:

  • Weight gain.
  • Mood swings
  • Decreased libido
  • Headache
  • Hot flushes
  • Rhinitis
  • Acne and seborrhea (excess oil on the skin)
  • Muscle aches
  • Decreased breast size
  • Vaginal dryness
  • Edema: swelling

Frequent adverse effects

Other symptoms of Synarel that also appear in numerous cases, although less frequently than the previous ones (in 1 out of every 100 patients), are the following:

  • Hypersensitivity to the drug: shortness of breath, chest pain, hives and itching
  • Estrogen deficiency and the beginning of artificial (surgical) menopause
  • Weight loss.
  • Depression and insomnia
  • Increased libido
  • Tingling sensation
  • Hypertension and hypotension
  • Irritation of the nasal mucosa
  • Hirsutism
  • Joint pain
  • Uterine bleeding
  • Decreased bone density

In the latter case, bone density recovers during the 6 months following the interruption of treatment, but it should be noted that if there is a family history of osteoporosis, the risk of suffering bone mineral loss is greater.

Less frequent and rare adverse effects

The rare symptoms of Synarel are those that appear in at least 1 in 1,000 patients, and in this case only alopecia, breast enlargement and ovarian cysts have been described.

For the rarest symptoms, which only appear in 1 in 10,000 patients, elevation of liver enzymes (GOT/GPT and serum alkaline phosphatase) is specified. Other side effects are also possible and their frequency is unknown. These include migraine, blurred vision, palpitations and ovarian hyperstimulation syndrome.

All the information published in this article has been extracted from the Vademecum (a treaty containing the composition, indications, side effects, etc. of each of the existing medicines on the market)

FAQs from users

How long should Synarel be taken?

By Sara Salgado B.Sc., M.Sc. (embryologist).

The duration of treatment should always be indicated by the doctor. In general, if used for ovarian stimulation prior to assisted reproduction treatment, the treatment period does not usually exceed 8 weeks. If it is used for the treatment of endometriosis the maximum recommended duration of treatment is 6 months.

Can I drink alcohol while taking Synarel?

By Sara Salgado B.Sc., M.Sc. (embryologist).

Both alcohol and tobacco are contraindicated during the use of Synarel, as they can interfere with the effectiveness of the treatment.

Can Synarel interact with other drugs like Ibuprofen?

By Sara Salgado B.Sc., M.Sc. (embryologist).

It is important to inform the doctor of any medications that the patient is taking or has recently taken prior to the use of Synarel to ensure that they are properly absorbed.

There does not appear to be an interaction between Synarel and anti-inflammatory drugs such as Ibuprofen. However, nasal decongestants decrease the absorption of Synarel, so they should not be used within 30 minutes of administration.

Can Synarel (Nafarelin acetate) be used to treat endometriosis?

By Zaira Salvador B.Sc., M.Sc. (embryologist).

Yes, it is a common hormonal treatment prescribed to relieve the symptoms of endometriosis. It is a nasal spray which main active ingredient is Nafarelin acetate, a GnRH agonist.

Can Synarel be used with Gonal, Ovitrelle or Menopur?

By Sara Salgado B.Sc., M.Sc. (embryologist).

Yes, it is common for a doctor to prescribe a combination of drugs to stimulate the ovary before IVF. Synarel allows the production of FSH and LH to be increased by acting directly on the release of GnRH. On the other hand, the use of Gonal involves the administration of FSH, while Menopur contains FSH and LH. With these three drugs, separately or in combination, the growth of the ovarian follicles can be stimulated. Finally, with Ovitrelle, which is hCG, the final maturation of the follicles and ovulation can be triggered.

It is important to note that the doctor adapts the stimulation protocol to each patient, so there will be differences in medication between women and others.

Can I treat endometriosis with Synarel when I am pregnant?

By Sara Salgado B.Sc., M.Sc. (embryologist).

No. Synarel can only be used if it is certain that there is no pregnancy. This medication should not be used if a positive pregnancy test or suspicion of pregnancy exists. Your doctor will prescribe a drug that is compatible with pregnancy or will postpone treatment. Synarel is not compatible with breastfeeding, either.

Is Synarel the same as Decapeptyl?

By Zaira Salvador B.Sc., M.Sc. (embryologist).

No. Although both drugs can be used during ovarian stimulation, Synarel and Decapeptyl contain different active ingredients.

On the one hand, Synarel is composed of nafarelin, while Decapepyl contains triptorelin. Even so, both components are GnRH agonists, so they have the same function: to block the pituitary gland to keep the ovaries at rest.

Suggested for you

As we have indicated throughout the article, Synarel is a drug used in fertility treatments during the ovarian stimulation phase. If you want to know what this part of the treatment is like and what other types of drugs are used, you can read on here: What is ovarian stimulation?

We make a great effort to provide you with the highest quality information.

🙏 Please share this article if you liked it. 💜💜 You help us continue!


Authors and contributors

 Neus Ferrando Gilabert
Neus Ferrando Gilabert
B.Sc., M.Sc.
Bachelor's Degree in Biology from the University of Valencia (UV). Postgraduate Course in Biotechnology of Human Assisted Reproduction from the Miguel Hernández University of Elche (UMH). Experience managing Embryology and Andrology Labs at Centro Médico Manzanera (Logroño, Spain). More information about Neus Ferrando Gilabert
 Sara Salgado
Sara Salgado
B.Sc., M.Sc.
Degree in Biochemistry and Molecular Biology from the University of the Basque Country (UPV/EHU). Master's Degree in Human Assisted Reproduction from the Complutense University of Madrid (UCM). Certificate of University Expert in Genetic Diagnosis Techniques from the University of Valencia (UV). More information about Sara Salgado
 Zaira Salvador
Zaira Salvador
B.Sc., M.Sc.
Bachelor's Degree in Biotechnology from the Technical University of Valencia (UPV). Biotechnology Degree from the National University of Ireland en Galway (NUIG) and embryologist specializing in Assisted Reproduction, with a Master's Degree in Biotechnology of Human Reproduction from the University of Valencia (UV) and the Valencian Infertility Institute (IVI) More information about Zaira Salvador
License: 3185-CV
Adapted into english by:
 Romina Packan
Romina Packan
inviTRA Staff
Editor and translator for the English and German edition of inviTRA. More information about Romina Packan

Find the latest news on assisted reproduction in our channels.