Endometriosis: Synarel (Naferelin acetate) General Info

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endoNafarelin acetate is the generic name for “Synarel,” a medicine that is used to treat endometriosis. It is a type of gonatropin-releasing hormone agonist (GnRH agonist) medicine. GnRH agonist medicines help to lessen pelvic pain caused by endometriosis.

How does Synarel work?

Synarel works by shutting off hormones made by the ovaries, so estrogen (one of the hormones that cause your body to have periods) is lowered. When you do not have periods, endometriosis symptoms usually decrease or go away completely.

How is Synarel taken?

Synarel is a nasal spray that is typically prescribed as: 1 or 2 sprays in one nostril in the morning and 1or 2 sprays (in the other nostril) in the evening (about 12 hours apart). It is very important to take Synarel at the same times every day without missing any doses.

Are there any reasons that I shouldn’t take Synarel?

You should NOT take Synarel if:

  • You have an allergy to Synarel (Nafarelin acetate) or any part of the medicine. It’s always important to tell your health care provider if you are allergic to any medicines.
  • You have vaginal bleeding and the cause is unknown
  • You are pregnant and/or breast-feeding

*Make sure you tell your health care provider about all of the medicines you take including over-the-counter herbs and supplements.

Before starting Synarel you should:

  • Have a pregnancy test (if you are having sex)
  • Talk to your health care provider (HCP) about whether you are at a higher risk for bone density problems (how solid and strong your bones are) and whether you need to have a bone density test before you start the medicine.
  • Know that it usually takes a few cycles to see an improvement in symptoms.

What are the possible side effects of Synarel?

All medications can cause side effects. Some people have mild side effects; most people have no side effects. Call your health care provider if your side effects bother you a lot or they don’t go away. Taking Synarel alone (without add-back) lowers the estrogen level in your body, which typically causes side effects that are similar to menopause. These side effects may include:

  • hot flashes or feeling warm-hot with flushing of the skin
  • moodiness
  • decreased interest in sex
  • acne
  • vaginal dryness
  • headache

Nasal irritation and/or a runny nose are also possible. Serious side effects are rare.

Other uncommon side effects that you should tell your health care provider about include:

  • inflammation/irritation of your nose
  • rash
  • pain in your belly area
  • heavy vaginal bleeding
  • vaginal spotting/bleeding for more than 2 months
  • sadness or symptoms of depression that lasts longer than 2 weeks
  • trouble with remembering things
If you experience chest pain or pressure in your chest area, irregular heartbeat and/or trouble breathing, you should go to the closest emergency department.

Where should I keep my Synarel?

  • Store it upright, in a dry place (not in the bathroom)
  • NEVER keep Synarel in the refrigerator or freezer
  • Protect it from direct sunlight
  • Keep it away from young children and pets

Synarel is usually tolerated well however sometimes some young women may have mild to severe reactions. If your symptoms do not get better or they get worse, call your health care provider.