Ganirelix

Pronunciation

(ga ni REL ix)

U.S. Brand Names

Antagon®

Synonyms

Ganirelix Acetate

Generic Available

No

Canadian Brand Names

Antagon®; Orgalutran®

Use

Inhibits premature luteinizing hormone (LH) surges in women undergoing controlled ovarian hyperstimulation in fertility clinics.

Pregnancy Risk Factor

X

Pregnancy Implications

Fetal resorption occurred in pregnant rats and rabbits. These effects are results of hormonal alterations and could result in fetal loss in humans. The drug should not be used in pregnant women.

Lactation

Excretion in breast milk unknown/not recommended

Contraindications

Hypersensitivity to ganirelix or any component of the formulation; hypersensitivity to gonadotropin-releasing hormone or any other analog; known or suspected pregnancy

Warnings/Precautions

Should only be prescribed by fertility specialists. The packaging contains natural rubber latex (may cause allergic reactions). Pregnancy must be excluded before starting medication.

Adverse Reactions

1% to 10%:

Central nervous system: Headache (3%)

Endocrine & metabolic: Ovarian hyperstimulation syndrome (2%)

Gastrointestinal: Abdominal pain (5%), nausea (1%), and abdominal pain (1%)

Genitourinary: Vaginal bleeding (2%)

Local: Injection site reaction (1%)

<1%: Congenital abnormalities

Drug Interactions

No formal studies have been performed

Stability

Store at controlled room temperature of 15°C to 30°C (59°F to 86°F)

Mechanism of Action

Competitively blocks the gonadotropin-release hormone receptors on the pituitary gonadotroph and transduction pathway. This suppresses gonadotropin secretion and luteinizing hormone secretion preventing ovulation until the follicles are of adequate size.

Pharmacodynamics/Kinetics

Absorption: SubQ: Rapid

Distribution: Mean Vd: 43.7 L

Protein binding: 81.9%

Metabolism: Hepatic to two primary metabolites (1-4 and 1-6 peptide)

Bioavailability: 91.1%

Half-life elimination: 16.2 hours

Time to peak: 1.1 hours

Excretion: Feces (75%) within 288 hours; urine (22%) within 24 hours

Dosage

Adult: SubQ: 250 mcg/day during the mid-to-late phase after initiating follicle-stimulating hormone on day 2 or 3 of cycle. Treatment should be continued daily until the day of chorionic gonadotropin administration.

Monitoring Parameters

Ultrasound to assess the follicle's size

Patient Education

This drug can only be given by injection as demonstrated. Use this and any other medications as directed by prescriber; do not skip any doses. You must keep all scheduled ultrasound appointments. You may experience headache (use of mild analgesic may help); or nausea (small, frequent meals, good mouth care, chewing gum, or sucking hard candy may help). Report immediately any sudden or acute abdominal pain; vaginal bleeding; or pain, itching, or signs of infection at injection site. Note: Packaging contains natural rubber latex; if you have a known latex allergy advise prescriber. Pregnancy/breast-feeding precautions: Do not get pregnant while taking this drug. Breast-feeding is not recommended.

Nursing Implications

Teach patient/spouse to give SubQ injections. Discuss ultrasound schedule and timing of other medications used.

Dental Health: Effects on Dental Treatment

No significant effects or complications reported

Dental Health: Vasoconstrictor/Local Anesthetic Precautions

No information available to require special precautions

Mental Health: Effects on Mental Status

None reported

Mental Health: Effects on Psychiatric Treatment

None reported

Dosage Forms

Injection, solution, as acetate: 250 mcg/0.5 mL [prefilled glass syringe with 27-gauge x ¹/2 inch needle]

International Brand Names

Antagon® (CA); Orgalutran® (AT, CA, CH, CY, CZ, DE, DK, EG, ES, FR, GB, IL, IT, JO, KW, LB, NL, NO, NZ, PL, RO, SE, SY, TH, YU)