Leuprolide
FDA ApprovedLeuprolide
A GnRH agonist and one of the first peptide drugs widely used clinically. Used for prostate cancer, endometriosis, and hormonal regulation research.
Dose
Variable, ranges from 20 mcg/day to 45 mg every 6 months depending on formulation and research application.
Route
SubQ injection, Intramuscular, Implant
Cycle
Variable, depending on research goals; can be continuous for chronic conditions or defined periods for specific studies.
Storage
Store at 20-25°C (68-77°F) or as specified by manufacturer; protect from light.
What is Leuprolide?
Leuprolide is a synthetic nonapeptide analog of gonadotropin-releasing hormone (GnRH). It acts as a GnRH receptor agonist, initially stimulating the release of gonadotropins (LH and FSH) from the pituitary gland. However, continuous administration leads to desensitization and down-regulation of GnRH receptors, resulting in a profound and sustained suppression of gonadotropin release. This, in turn, leads to a significant reduction in ovarian and testicular steroidogenesis, effectively suppressing estrogen and testosterone production. This mechanism is exploited in research contexts involving conditions sensitive to sex hormones, such as prostate cancer, endometriosis, and precocious puberty. Various formulations exist, ranging from daily subcutaneous injections to long-acting intramuscular depot injections and subcutaneous implants, allowing for flexible research protocols.
Key Benefits
- Testosterone suppression (clinical use)
- Hormonal regulation
- Prostate cancer management
- Endometriosis research
Mechanism of Action
- GnRH receptor agonist
- Initial flare followed by testosterone suppression
- Downregulates GnRH receptors
Best For
- Hormonal research
- Advanced reproductive research
Body Systems
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Molecular Information
Molecular weight
1209.39 g/mol
Length
9
Type
Synthetic Nonapeptide, GnRH Agonist
Amino acid sequence
Pyr-His-Trp-Ser-Tyr-D-Leu-Leu-Arg-Pro-NHEt
A synthetic analog of Gonadotropin-Releasing Hormone (GnRH) with a D-leucine substitution at position 6 and ethylamide modification at the C-terminus, which increases its potency and half-life compared to native GnRH.
Pharmacokinetics
Time to peak
1-2 hours for subcutaneous injection; days to weeks for depot formulations.
Half-life
3 h
Time to clear
Elimination half-life is approximately 3 hours for subcutaneous formulations; depot formulations provide sustained release over weeks to months.
Research literature consistently reports a short elimination half-life for the active compound, but depot formulations achieve prolonged release.
Research Indications
Prostate Cancer
Widely researched for androgen deprivation therapy (ADT) in hormone-sensitive and advanced prostate cancer, leading to testosterone suppression.
Research Protocols
| Goal | Dose | Frequency | Route |
|---|---|---|---|
| Testosterone Suppression for Prostate Cancer Models | Variable, e.g., 7.5 mg, 22.5 mg, 30 mg, or 45 mg | Monthly, every 3 months, or every 6 months (depot formulations) | Intramuscular (IM) or Subcutaneous (SC) for depot |
| Estrogen Suppression for Endometriosis Models | 3.75 mg | Monthly (depot formulation) | Intramuscular (IM) |
| Suppression of Precocious Puberty in Animal Models | Variable, e.g., 20 mcg/kg/day or specific depot doses based on animal weight | Daily (SC) or Monthly (depot) | Subcutaneous (SC) or Intramuscular (IM) |
| Pituitary Down-regulation in ART Research | 0.5 mg to 1 mg | Daily for 7-14 days or until down-regulation is confirmed, then lower dose (e.g., 0.25 mg daily) during stimulation phase | Subcutaneous (SC) |
| Long-term Androgen Deprivation in Male Models | Varied based on formulation | Every 3 or 6 months (depot) | Intramuscular (IM) or Subcutaneous (SC) |
Timing is crucial; daily subcutaneous injections require consistent daily administration. Depot formulations (monthly, quarterly, or every 6 months) require precise scheduling for administration to maintain continuous hormone suppression.
Peptide Interactions
- Avoid
Androgens (e.g., testosterone)
Leuprolide suppresses androgen production; co-administration would counteract its primary mechanism of action for androgen deprivation.
- Avoid
Estrogens (e.g., estradiol)
Leuprolide suppresses estrogen production; co-administration would counteract its primary mechanism of action for estrogen deprivation.
- Use Caution
Other GnRH Agonists or Antagonists
Concomitant use is generally not recommended as it could lead to excessive or conflicting hormonal effects, or interfere with monitoring.
- Monitor Combination
Drugs affecting pituitary function
Co-administration with compounds that alter pituitary gonadotropin release could modify leuprolide's intended effects; close monitoring is advised.
- Compatible
Corticosteroids
Generally considered compatible; corticosteroids may be used concurrently to manage certain conditions or side effects, with monitoring.
How to Reconstitute
- 1Verify the specific formulation and its reconstitution instructions (e.g., lyophilized powder for depot vs. pre-mixed solution).
- 2If lyophilized, allow the vial to reach room temperature before reconstitution.
- 3Using an appropriate diluent (often sterile water for injection or a specific solvent provided), inject the diluent into the vial, aiming for the side wall.
- 4Gently swirl the vial to dissolve the powder; do not shake vigorously to avoid foaming.
- 5Ensure complete dissolution, which may take several minutes for some depot formulations, forming a uniform suspension.
- 6Withdraw the reconstituted solution/suspension using an appropriate syringe and needle, ensuring all particles are evenly dispersed for depot formulations.
Specific reconstitution instructions vary significantly between leuprolide formulations (e.g., daily injectable vs. depot). Always refer to the manufacturer's specific instructions for the particular product being used.
What to Expect
- Weeks 1-2: Initial 'flare' in LH, FSH, testosterone/estradiol levels may be observed due to receptor stimulation before desensitization.
- Weeks 2-4: Hormone levels (testosterone/estradiol) begin to decrease significantly as pituitary desensitization becomes established.
- Months 1-3: Sustained suppression of target hormones is typically achieved and maintained, depending on the formulation used.
- Months 3-6+: Long-term studies observe continued suppression with depot formulations. Reversal of effects upon cessation varies, typically taking weeks to months.
- General: Monitoring of relevant hormone levels (e.g., testosterone, estradiol) is commonly discussed in research protocols to confirm efficacy.
Side Effects & Safety
| Effect | Frequency | Severity |
|---|---|---|
| Hot flashes | Very Common | Mild |
| Testosterone suppression | Intended clinical effect | Significant |
| Bone density loss with chronic use | With chronic use | Serious |
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