Synarel


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nafarelin acetate

Synarel

Pharmacologic class: Gonadotropin-releasing hormone (GnRH)

Therapeutic class: Hormone

Pregnancy risk category X

Action

Inhibits secretion of gonadotropin, a luteinizing hormone (LH)-releasing hormone. Initially increases pituitary production of LH and follicle-stimulating hormone (FSH), which ultimately leads to deactivation of testicular and ovarian functions.

Availability

Nasal spray: 2 mg/ml in 10-ml bottle (200 mcg/spray)

Indications and dosages

Endometriosis

Adults: One spray (200 mcg) intra-nasally in one nostril in morning and one spray in other nostril in evening (400 mcg/day). May increase to one spray in each nostril in morning and evening (800 mcg/day).

Central precocious puberty

Children: Two sprays in each nostril in morning and evening (1,600 mcg/day). May increase up to 1,800 mcg/day (three sprays in alternating nostrils t.i.d.).

Contraindications

• Hypersensitivity to GnRH, its analogs, or sorbitol

• Undiagnosed abnormal vaginal bleeding

• Pregnancy or breastfeeding

Precautions

Use cautiously in:

• rhinitis, ovarian cysts, major risk factors for bone density loss (such as chronic alcoholism or chronic corticosteroid use).

Administration

• Make sure patient isn't pregnant before starting therapy.

• For endometriosis, start therapy on day 2 to day 4 of menstrual period.

• If patient needs topical decongestant, wait at least 2 hours after nafarelin dose before giving.

• Know that retreatment for endometriosis isn't recommended.

Adverse reactions

CNS: emotional lability, headache, depression, insomnia, seizures

CV: chest pain, thromboembolism

EENT: nasal irritation, rhinitis

GU: vaginal dryness, bleeding, or discharge; menses cessation; transient breast enlargement; decreased libido

Musculoskeletal: reduced bone density, myalgia

Respiratory: dyspnea

Skin: urticaria, rash, pruritus, acne, oily skin, hirsutism, transient pubic hair increase

Other: weight changes, hot flashes, edema, body odor, hypersensitivity reaction

Interactions

Drug-drug. Topical nasal decongestants: reduced nafarelin absorption

Patient monitoring

• Monitor patient for emotional lability or depression.

• Assess nasal mucosa for erosion.

• Monitor vital signs. Weigh patient regularly; report edema.

• Stay alert for adverse hormonal effects, including hot flashes, menses cessation followed by breakthrough bleeding, hirsutism, acne, decreased libido, and vaginal dryness.

Closely monitor patient for signs and symptoms of seizures and thromboembolism.

Patient teaching

• Instruct patient to complete entire course of therapy. Advise her to keep enough of drug on hand to prevent interruption.

• Inform patient that regular menstruation should cease after 4 to 6 weeks of therapy but that breakthrough bleeding may still occur.

• Tell patient ovulation may still occur. Instruct her to use barrier contraception during therapy and to report suspected pregnancy.

• Caution patient not to breastfeed.

• Teach patient about adverse hormonal effects. Identify which signs and symptoms to report.

• Inform patient that drug may cause emotional changes or depression. Advise her to report these to prescriber.

Instruct patient to immediately report signs and symptoms of seizures and thromboembolism.

• As appropriate, review all other significant adverse reactions and interactions, especially those related to the drugs mentioned above.

nafarelin

(na-fare-e-lin) ,

Synarel

(trade name)

Classification

Therapeutic: hormones
Pharmacologic: gonadotropin releasing hormones
Pregnancy Category: X

Indications

Endometriosis.Central precocious puberty (gonadotropin-dependent) in children.

Action

Acts as a synthetic analogue of gonadotropin-releasing hormone (GnRH). Initially increases pituitary production of luteinizing hormone (LH) and follicle-stimulating hormone (FSH), which cause ovarian steroid production. Chronic administration leads to decreased production of gonadotropins. Endometriotic lesions are sensitive to ovarian hormones.

Therapeutic effects

Reduction in lesions and associated pain in endometriosis.
Arrest and regression of puberty in children with central precocious puberty.

Pharmacokinetics

Absorption: Well absorbed following intranasal administration.
Distribution: Unknown.
Metabolism and Excretion: 20–40% excreted in feces; 3% excreted unchanged by the kidneys.
Half-life: 3 hr.

Time/action profile (↓ ovarian steroid production)

ROUTEONSETPEAKDURATION
Intranasalwithin 4 wk3–4 wk3–6 mo†
†Relief of symptoms of endometriosis following discontinuation

Contraindications/Precautions

Contraindicated in: Hypersensitivity to GnRH, its analogues, or sorbitol; Obstetric / Lactation: Pregnancy or lactation.
Use Cautiously in: Rhinitis.

Adverse Reactions/Side Effects

Central nervous system

  • stroke (life-threatening)
  • emotional instability (most frequent)
  • headaches (most frequent)
  • depression
  • insomnia

Ear, Eye, Nose, Throat

  • nasal irritation (most frequent)

Cardiovascular

  • Myocardial infarction (life-threatening)
  • edema

Genitourinary

  • vaginal dryness (most frequent)

Dermatologic

  • acne (most frequent)
  • hirsutism
  • seborrhea

Endocrinologic

  • cessation of menses (most frequent)
  • impaired fertility (most frequent)
  • ↓ breast size (most frequent)

Metabolic

  • hyperglycemia

Musculoskeletal

  • ↓ bone density
  • myalgia

Miscellaneous

  • ↓ libido (most frequent)
  • hot flashes (most frequent)
  • hypersensitivity reactions
  • weight gain

Interactions

Drug-Drug interaction

Concurrent topical nasal decongestants may ↓ absorption of nafarelin (administer decongestant at least 2 hr after nafarelin).

Route/Dosage

Intranasal (Adults) Endometriosis—1 spray (200 mcg) in 1 nostril in the morning and 1 spray in the other nostril in the evening (400 mcg/day). May ↑ to 1 spray in each nostril in the morning and evening (800 mcg/day).
Intranasal (Children) Central precocious puberty—2 sprays in each nostril in the morning and in the evening (1600 mcg/day); may ↑ up to 1800 mcg/day (3 sprays in alternating nostrils 3 times daily).

Availability

Nasal spray: 2 mg/mL (200 mcg/spray)

Nursing implications

Nursing assessment

  • Endometriosis: Assess patient for endometriotic pain periodically during therapy.
  • Central Precocious Puberty: Prior to therapy, a complete physical and endocrinologic examination including height, weight, hand and wrist x-ray, total sex steroid level (estradiol or testosterone), adrenal steroid level, beta human chorionic gonadotropin level, GnRH stimulation test, pelvic/adrenal/testicular ultrasound, and CT of the head must be performed. These parameters are monitored after 6–8 wk and every 3–6 mo during therapy.
    • Assess patient for signs of precocious puberty (menses, breast development, testicular growth) periodically during therapy.
    • Nafarelin is discontinued when the onset of normal puberty is desired. Monitor the onset of normal puberty and assess menstrual cycle, reproductive function, and final adult height.

Potential Nursing Diagnoses

Acute pain (Indications)
Sexual dysfunction (Indications,  Side Effects)

Implementation

  • Endometriosis: Treatment should be started between days 2 and 4 of the menstrual cycle and continued for up to 6 mo.

Patient/Family Teaching

  • Instruct patient on the correct technique for nasal spray: The head should be tilted back slightly; wait 30 sec between sprays.
    • Advise patient to consult health care professional if rhinitis occurs during therapy. If a topical decongestant is needed, do not use decongestant until 2 hr after nafarelin dosing. If possible, avoid sneezing during and immediately after nafarelin dose.
  • Endometriosis: Inform patient that 1 spray should be administered into 1 nostril in the morning and 1 spray into the other nostril in the evening for the 400 mcg/day dose. If dose is increased to 800 mcg/day, administer 1 spray to each nostril (2 sprays) morning and evening; 1 bottle should provide a 30-day supply at the 400 mcg/day dose.
    • Advise patient to use a form of contraception other than oral contraceptives during therapy. Inform patient that amenorrhea is expected. Instruct patient to notify health care professional if regular menstruation persists or if successive doses are missed.
    • Advise patient that medication may cause hot flashes. Notify health care professional if these become bothersome.
  • Central Precocious Puberty: Instruct patient on correct timing and number of sprays. The 1600 mcg/day dose is achieved by 2 sprays to each nostril in the morning (4 sprays) and 2 sprays to each nostril in the evening (4 sprays), for a total of 8 sprays. The 1800 mcg/day dose is achieved by 3 sprays into alternating nostrils 3 times per day, for a total of 9 sprays. Inform patient and parents that if doses are not taken as directed pubertal process may be reactivated. One bottle should provide a 7-day supply at the 1600 mcg/day dose.
    • Advise patient and parents that during 1st mo of therapy some signs of puberty (vaginal bleeding, breast enlargement) may occur. These should resolve after the 1st mo of therapy. If these signs persist after the 2nd mo of therapy, notify health care professional.

Evaluation/Desired Outcomes

  • Reduction in lesions and associated pain in endometriosis.
  • Resolution of the signs of precocious puberty.

Synarel

A brand name for NAFARELIN.
References in periodicals archive ?
The firm shows promise in Cardene (a calcium-channel blocker), Cytovene for treating an eye disease tied to AIDS, Toradol (an analgesic) and Synarel for endometriosis.
Examples of FDA-approved GnRH agonists include: Lupron (leuprorelin), Synarel (nafarelin), and Zoladex (goserelin).
Ask your health care professional about hormone-suppressing drugs, such as Lupron, Synarel and Zoladex.
Important new products include Toradol, a potent nonnarcotic analgesic; Cardene, a calcium channel blocker; Cytovene, an antiviral therapy; Synarel, a treatment for endometriosis; and Ticlid, an antistroke drug that received FDA approval last December.