Classifications: hormone; gonadotropin-releasing hormone (gnrh) antagonist;
Therapeutic: gnrh antagonist

Prototype: Ganirelix
Pregnancy Category: X


250 mcg/0.5 mL syringe


Ganirelix is a gonadotropin-releasing hormone (GnRH) antagonist that suppresses pituitary gonadotropins and sex hormones.

Therapeutic Effect

It prevents LH surges in reproductive protocols, and causes shrinkage of uterine fibroids.


Infertility treatment.


Prior hypersensitivity to ganirelix, LHRH, or other LHRH analogs, mannitol hypersensitivity; ovarian cyst; primary ovarian failure; pregnancy (category X), lactation.

Cautious Use

History of current allergic disorders (e.g., asthma, hay fever, urticaria, eczema) or a history of allergic reactions to medications; renal/hepatic dysfunction; endocrine disorders; alcohol consumption.

Route & Dosage

Adult: SC After initiating follicle-stimulating hormone (FSH) therapy on day 2 or 3 of the cycle, give 250 mcg once daily during the early-to-mid-follicular phase


  • Note: The packaging of the product, Antagon, contains natural rubber latex which may cause allergic reactions.
  • Inject SC into the abdomen around the umbilicus or into the upper thigh.
  • Rotate injection sites.
  • Store at 5°–30° C (59°–86° F) and protect from light.

Adverse Effects (≥1%)

CNS: Headache. GI: Abdominal pain, nausea. Endocrine: Ovarian hyperstimulation syndrome. Skin: Injection site reaction. Urogenital: Vaginal bleeding.


Drug: No clinically significant interactions established.


Absorption: 91% from SC site. Peak: 1 h. Distribution: 81% protein bound. Elimination: 75% in feces; 22% in urine. Half-Life: 13–16 h.

Nursing Implications

Assessment & Drug Effects

  • Exercise caution with patients with hypersensitivity to GnRH or with known allergic disorders (e.g., asthma, hay fever). These patients should be carefully monitored after the first injection for S&S of an anaphylactic reaction.
  • Lab tests: Monitor baseline and periodic CBC with differential, and periodic total bilirubin.

Patient & Family Education

  • Report menstrual disorders (e.g., spotting, frank vaginal bleeding) to physician.
  • Notify physician immediately if you think you are pregnant.

Common adverse effects in italic, life-threatening effects underlined; generic names in bold; classifications in SMALL CAPS; Canadian drug name; Prototype drug

© 2006-2018 Last Updated On: 03/17/2018 (0)
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