Abarelix

GnRH Antagonist PeptideRx: PrescriptionCompound: Withdrawn

Also known as: Abarelix, Abarelix acetate, GnRH antagonist decapeptide, Plenaxis, PPI-149, R-3827

Educational Only — Not medical advice. Consult a qualified clinician before using any peptide.

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Summary

Synthetic decapeptide GnRH antagonist formerly approved in Europe for advanced prostate cancer; withdrawn due to safety concerns and injection‑site reactions.

Mechanism of Action

Competitive antagonism of pituitary GnRH receptors, suppressing LH, FSH, and testosterone secretion

Routes of Administration

IntramuscularSubcutaneous

Goals & Uses

  • Palliative treatment of advanced prostate cancerOncologyHigh
  • Reduction of PSA levelsBiomarker ResponseHigh
  • Testosterone suppression to castrate levelsHormonal TherapyHigh
  • Prevention of testosterone flareOncology / Hormonal SafetyHigh
  • Advanced prostate cancerOncologyHigh

Contraindications

  • Hypersensitivity to abarelix or excipientsAllergyHigh
  • Patients who can be managed with LHRH agonistsClinical SuitabilityModerate
  • Female sex (women of childbearing potential)PopulationHigh
  • History of serious hypersensitivity to abarelixAllergyHigh
  • Hypersensitivity to abarelix or any excipientsAllergyHigh
  • Pediatric usePopulationHigh
  • QT prolongation / long QT syndromeCardiacHigh

Adverse Effects

  • Injection site reactionsLocalCommon
  • QTc prolongationCardiacUncommon
  • Elevated transaminasesHepaticUncommon
  • Hot flashesEndocrine / VasomotorCommon
  • NauseaGastrointestinalCommonFeeling of sickness or urge to vomit
  • Anaphylactic reactionsSystemicRare
  • Immediate-onset systemic allergic reactionImmunologicUncommon
  • Hot flushesVasomotorCommon
  • Elevated liver enzymesHepaticUncommonIncrease in AST/ALT or other hepatic markers
  • Decreased libido / erectile dysfunctionSexual / EndocrineCommon

Drug Interactions

  • CYP450 substratesLow
  • QT-prolonging agents (e.g., antiarrhythmics, antipsychotics)High
  • Anticoagulants (warfarin)Moderate

Population Constraints

  • Pediatric patientsAgeAbsolute
  • Patients with pre-existing QT prolongationCardiacRelative
  • Patients with hepatic impairmentOrgan FunctionRelative
  • WomenSexAbsolute
  • Male patients onlySexAbsolute

Regulatory Status

  • European UnionWithdrawnApproved: advanced prostate cancerWithdrawn from market in 2009 due to safety concerns
  • United StatesUnapprovedNever received FDA approval
  • United KingdomWithdrawnApproved: advanced prostate cancerFollowed EU withdrawal

Approved in EU (2003) as Plenaxis, later withdrawn; never approved in the US.

Evidence & Sources

No sources recorded yet.

Frequently Asked Questions

What is Abarelix?

Synthetic decapeptide GnRH antagonist formerly approved in Europe for advanced prostate cancer; withdrawn due to safety concerns and injection‑site reactions.

What is Abarelix used for?

Abarelix is educationally associated with: Palliative treatment of advanced prostate cancer, Reduction of PSA levels, Testosterone suppression to castrate levels, Prevention of testosterone flare, Advanced prostate cancer. Educational only — not medical advice.

How is Abarelix administered?

Recorded routes of administration: Intramuscular, Subcutaneous.

What are the potential side effects of Abarelix?

Reported adverse effects include: Injection site reactions, QTc prolongation, Elevated transaminases, Hot flashes, Nausea, Anaphylactic reactions, Immediate-onset systemic allergic reaction, Hot flushes, Elevated liver enzymes, Decreased libido / erectile dysfunction. This list is not exhaustive — consult a qualified clinician.

Who should avoid Abarelix?

Recorded contraindications: Hypersensitivity to abarelix or excipients, Patients who can be managed with LHRH agonists, Female sex (women of childbearing potential), History of serious hypersensitivity to abarelix, Hypersensitivity to abarelix or any excipients, Pediatric use, QT prolongation / long QT syndrome. Consult a qualified clinician before use.

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