Synarel Side Effects

Generic name: nafarelin

Medically reviewed by Drugs.com. Last updated on Aug 8, 2024.

Note: This document provides detailed information about Synarel Side Effects associated with nafarelin. Some dosage forms listed on this page may not apply specifically to the brand name Synarel.

Applies to nafarelin: nasal spray.

Serious side effects of Synarel

Along with its needed effects, nafarelin (the active ingredient contained in Synarel) may cause some unwanted effects. Although not all of these side effects may occur, if they do occur they may need medical attention.

Check with your doctor immediately if any of the following side effects occur while taking nafarelin:

More common side effects

For adults (female)

• breast enlargement
• light vaginal bleeding between regular menstrual periods, called spotting
• longer or heavier menstrual periods
• vaginal bleeding between regular menstrual periods, called breakthrough bleeding

For children (male)

• body odor
• growth of pubic hair

For children (female)

• body odor
• breast enlargement
• growth of pubic hair
• light vaginal bleeding between regular menstrual periods, called spotting
• longer or heavier menstrual periods
• vaginal bleeding between regular menstrual periods, called breakthrough bleeding

Less common side effects

• chest pain
• rash, hives or welts, itching
• redness of the skin

Less common or rare side effects

For adults (female)

• fast or irregular heartbeat
• numbness or tingling of the hands or feet
• pain in the eyes or joints
• patchy brown or dark brown discoloration of the skin
• pelvic bloating or tenderness
• unexpected or excess milk flow from the breasts
• unusual tiredness or weakness

Incidence not known

For adults (female)

• cough
• difficulty with speaking
• dizziness or lightheadedness
• double vision
• fainting
• fast heartbeat
• inability to move the arms, legs, or facial muscles
• inability to speak
• nausea
• pain or discomfort in the arms, jaw, back, or neck
• pain, redness, or swelling in the arm or leg
• slow speech
• sweating
• trouble breathing
• vomiting
• yellow eyes or skin

Incidence not known

• anxiety or mental depression
• blurred or double vision
• change in ability to see colors, especially blue or yellow
• changes in vision
• cold, clammy, or pale skin
• confusion
• discouragement
• eye pain
• feeling sad or empty
• headache
• irregular heartbeats
• irritability
• lack of appetite
• loss of interest or pleasure
• nightmares or unusually vivid dreams
• seizures
• slow heart rate
• trouble concentrating
• trouble sleeping
• vomiting
• weakness

Other side effects of Synarel

Some side effects of nafarelin may occur that usually do not need medical attention. These side effects may go away during treatment as your body adjusts to the medicine. Also, your health care professional may be able to tell you about ways to prevent or reduce some of these side effects.

Check with your health care professional if any of the following side effects continue or are bothersome or if you have any questions about them:

More common side effects

For adults (female)

• acne
• dandruff
• hot flashes
• increase or decrease in sexual desire
• increased hair growth, often abnormally distributed
• mood swings
• muscle pain
• oily skin
• pain during sexual intercourse
• rapid weight gain
• reduced breast size
• stopping of menstrual periods
• swelling of the feet or lower legs
• vaginal dryness

For children (male)

• acne
• dandruff
• mood swings
• oily skin

For children (female)

• acne
• dandruff
• hot flashes
• mood swings
• oily skin

Less common or rare side effects

For adults (female)

• breast pain
• headache (mild and transient)
• irritated or runny nose
• mental depression (mild and transient)

For children (male)

• irritated or runny nose

For children (female)

• irritated or runny nose
• white or brownish vaginal discharge

For healthcare professionals

Applies to nafarelin: nasal spray.

Cardiovascular adverse events

• Very common (10% or more): Hot flashes/hot flush (up to 90%)
• Common (1% to 10%): Chest pain, edema, hyper/hypotension
• Frequency not reported: Palpitations
• Postmarketing reports: Arterial thromboembolism, deep vein thrombosis, myocardial infarction, venous thromboembolism^[Ref]

Hot flashes occurred commonly in adult women who were treated for endometriosis. Approximately 3% of children developed transient hot flashes.^[Ref]

Psychiatric

• Very common (10% or more): Decreased libido (up to 23%), emotional/affect lability (up to 15%)
• Common (1% to 10%): Depression, increased libido, insomnia
• Postmarketing reports: Aggression, anger, impatience, irritability, suicidal ideation, suicide attempt^[Ref]

Genitourinary

• Very common (10% or more): Vaginal dryness (up to 19%)
• Common (1% to 10%): Transient breast enlargement, breast atrophy/decreased breast size, vulvovaginal dryness, artificial menopause, uterine hemorrhage, vaginal bleeding, white/brown vaginal discharge
• Uncommon (0.1% to 1%): Ovarian cyst
• Frequency not reported: Ovarian hyperstimulation syndrome^[Ref]

Nervous system

• Very common (10% or more): Headache (up to 18%)
• Common (1% to 10%): Paresthesia
• Frequency not reported: Migraines
• Postmarketing reports: Convulsions, stroke, transient ischemic attack^[Ref]

Dermatologic

• Very common (10% or more): Acne (up to 14%)
• Common (1% to 10%): Transient increase in pubic hair, body odor, seborrhea, pruritus, rash, urticaria, hirsutism
• Uncommon (0.1% to 1%): Alopecia^[Ref]

Respiratory

• Common (1% to 10%): Rhinitis, dyspnea, nasal irritation
• Frequency not reported: Shortness of breath
• Postmarketing reports: Interstitial pneumonitis, pulmonary embolism, pulmonary fibrosis^[Ref]

Musculoskeletal

• Common (1% to 10%): Myalgia, decreased bone mineral density
• Uncommon (0.1% to 1%): Arthralgia
• Postmarketing reports: Arthritic symptoms^[Ref]

Endocrine

• Common (1% to 10%): Estrogen deficiency
• Frequency not reported: Pituitary enlargement/asymmetry/pituitary gland changes (size and shape)
• Postmarketing reports: Pituitary apoplexy^[Ref]

Metabolic

• Common (1% to 10%): Increased/decreased weight
• Frequency not reported: Increased serum alkaline phosphatase, increased total cholesterol/triglycerides^[Ref]

Hypersensitivity

• Common (1% to 10%): Drug hypersensitivity^[Ref]

Oncologic

• Frequency not reported: Adrenal rest tumor of the testis, pituitary gland adenoma^[Ref]

A patient with congenital adrenal hyperplasia developed an adrenal rest tumor 8 months after discontinuing treatment; however, correlation to treatment is unlikely.

Pituitary gland adenomas have been observed in a few children receiving treatment; however, the relationship to treatment is unknown.^[Ref]

Hepatic

• Frequency not reported: Increased AST/ALT, serious liver injury^[Ref]

Ocular

• Frequency not reported: Blurred vision^[Ref]

Other

• Postmarketing reports: Crying

Further information

Synarel side effects can vary depending on the individual. Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.

Note: Medication side effects may be underreported. If you are experiencing side effects that are not listed, submit a report to the FDA by following this guide.

Medical Disclaimer