Degarelix
FDA ApprovedDegarelix
An FDA-approved GnRH antagonist used for prostate cancer. Unlike GnRH agonists, it immediately suppresses testosterone without an initial flare.
Dose
80 mg (maintenance dose) or 240 mg (loading dose)
Route
SubQ injection (depot)
Cycle
Variable, dependent on research objectives
Storage
Store in original packaging at 2-8°C (36-46°F), protect from light
What is Degarelix?
Degarelix is a synthetic linear decapeptide, a potent and selective antagonist of gonadotropin-releasing hormone (GnRH) receptors. Unlike GnRH agonists, which initially stimulate hormone release before down-regulating receptors, degarelix directly binds to and blocks GnRH receptors in the pituitary gland. This action immediately suppresses the release of luteinizing hormone (LH) and follicle-stimulating hormone (FSH), leading to a rapid reduction in testosterone production by the testes. This rapid and sustained testosterone suppression without the initial 'testosterone flare' often seen with GnRH agonists makes it a focus in research for hormone-sensitive conditions, particularly prostate cancer. It is commonly administered via subcutaneous injection as a depot formulation.
Key Benefits
- Rapid testosterone suppression
- No testosterone flare (vs agonists)
- Hormone-sensitive cancer management
Mechanism of Action
- GnRH receptor antagonist (not agonist)
- Immediately blocks receptor
- Rapid testosterone reduction within days
Best For
- Hormone-sensitive cancer research
- Advanced hormonal research
Body Systems
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Molecular Information
Molecular weight
1631.90 g/mol
Length
10
Type
Decapeptide
Amino acid sequence
Ac-D-2-Nal-D-4-Cpa-D-3-Pal-Ser-4-Aph(Hor)-D-4-Aph(Hor)-Leu-Ile-Lys-Pro-D-Ala-NH2
Ac: N-terminal acetyl group; D-2-Nal: D-2-naphthylalanine; D-4-Cpa: D-4-chlorophenylalanine; D-3-Pal: D-3-pyridylalanine; 4-Aph(Hor): 4-aminophenylalanine(hydroorotyl)
Pharmacokinetics
Time to peak
1-3 days (loading dose), 3 days (maintenance dose)
Half-life
672 h
Time to clear
Approximately 2-3 months after last dose (for full testosterone recovery)
Clinical Pharmacology and Pharmacokinetics of Degarelix
Research Indications
Androgen Deprivation Therapy (ADT)
Research extensively investigates degarelix as a GnRH antagonist for ADT in hormone-sensitive prostate cancer, focusing on its rapid testosterone suppression without flare.
Metastatic Prostate Cancer
Studies explore degarelix's role in managing metastatic prostate cancer, particularly in patients where rapid testosterone reduction is critical.
Prior to Radiation Therapy
Research examines its use as neoadjuvant or adjuvant therapy before or during radiation in certain prostate cancer cases.
Research Protocols
| Goal | Dose | Frequency | Route |
|---|---|---|---|
| Initial Testosterone Suppression in Prostate Cancer Models | 240 mg (loading dose) | Single dose | Subcutaneous |
| Maintenance of Castration Levels in Prostate Cancer Models | 80 mg | Monthly | Subcutaneous |
| Comparative Studies with GnRH Agonists | 240 mg loading, then 80 mg monthly | Single loading then monthly | Subcutaneous |
| Evaluation of Cardiovascular Safety in ADT | Standard therapeutic doses (e.g., 240 mg loading, then 80 mg monthly) | Monthly | Subcutaneous |
| Assessment of Bone Mineral Density Changes with Long-term Use | Standard therapeutic doses (e.g., 240 mg loading, then 80 mg monthly) | Monthly (for extended periods) | Subcutaneous |
The initial loading dose is crucial for rapid testosterone suppression, followed by consistent monthly maintenance doses.
Peptide Interactions
- Use Caution
QT-prolonging drugs (e.g., Class IA antiarrhythmics, tricyclic antidepressants)
Concomitant use may increase the risk of QT interval prolongation. ECG monitoring and careful consideration are commonly discussed in research protocols.
- Monitor Combination
CYP3A4 inhibitors/inducers
While degarelix is not primarily metabolized by CYP enzymes, potential interactions with strong inhibitors or inducers of CYP3A4 should be monitored, as minor metabolic pathways or transporter interactions could exist. However, direct clinically significant interactions are generally not expected based on current data.
- Monitor Combination
Anticoagulants (e.g., Warfarin)
Degarelix may affect liver function which could theoretically influence the metabolism of anticoagulants. Coagulation parameters are commonly monitored when these are co-administered in research.
- Avoid
Other GnRH antagonists or agonists
Concurrent administration of other GnRH analogues is generally avoided as their mechanisms are either redundant or antagonistic in a manner that could complicate therapeutic outcomes or interpretation of research data.
How to Reconstitute
- 1Ensure the vial and pre-filled syringe are at room temperature.
- 2Attach the transfer needle to the pre-filled syringe containing sterile water for injection.
- 3Inject the entire contents of the syringe into the degarelix powder vial, aiming for the glass wall to avoid foaming.
- 4Gently swirl the vial in a circular motion until the powder is completely dissolved and a clear, colorless to pale yellow solution is formed (usually within minutes). Do not shake vigorously.
- 5Withdraw the entire reconstituted solution into the syringe. Replace the transfer needle with a suitable injection needle.
- 6Administer the injection immediately.
Reconstitution should be performed carefully to ensure a clear solution free of particulate matter, which is then administered subcutaneously.
What to Expect
- Within 1-3 days (Week 1): Rapid decrease in serum testosterone levels, typically reaching castration levels (<50 ng/dL).
- Within 2-4 weeks: Sustained suppression of testosterone with the first maintenance dose.
- Monthly (Ongoing): Continued maintenance of suppressed testosterone levels with subsequent monthly injections.
- Long-term: Potential for symptomatic relief related to testosterone suppression in hormone-sensitive conditions.
- Potential injection site reactions (pain, redness, swelling) are common, especially in the first few days post-injection.
Side Effects & Safety
| Effect | Frequency | Severity |
|---|---|---|
| Injection site reactions | Very Common | Mild-Moderate |
| Hot flashes | Very Common | Mild |
| Weight gain | Common | Mild |
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Open CalculatorPeptides discussed here are for research purposes only. Nothing on this page is medical advice. Always consult a qualified professional before making health decisions.