Triptorelin
also known as Trelstar, Decapeptyl, Diphereline, GnRH agonist
Synthetic decapeptide gonadotropin-releasing hormone (GnRH) agonist, FDA-approved for advanced prostate cancer, endometriosis, and central precocious puberty. Initial pituitary flare (1–3 weeks) followed by receptor downregulation produces sustained suppression of LH, FSH, and downstream sex hormones. Available in 1-month, 3-month, and 6-month depot formulations. Distinguished by biphasic mechanism: transient stimulation, then prolonged castration-level testosterone (<50 ng/dL).
At a glance
IM · Depot Injection · Monthly to 6-Monthly
Primary target — Pituitary GnRH receptors [anon-2012].
Pathway — GnRH receptor agonism → initial flare (LH/FSH spike) → receptor desensitization → sustained LH/FSH suppression.
Downstream effect — Castration-level suppression of testosterone (men) and estrogen (women) within 2–4 weeks post-flare.
Origin — Synthetic decapeptide analogue of native GnRH with amino acid substitutions for enhanced receptor affinity and stability.
Feedback intact — No — bypasses physiological pulsatility; continuous agonism produces paradoxical suppression.
| Parameter | Value |
|---|---|
| 1-month depot | 3.75 mg IMMost common formulation for prostate cancer. |
| 3-month depot | 11.25 mg IM [yee-2025]Reduced injection frequency. |
| 6-month depot | 22.5 mg IM [yee-2025][chen-2024]Long-acting formulation; improved adherence in real-world use. [yee-2025] |
| Administration route | Intramuscular (IM) — gluteal or deltoid |
| Frequency | Every 1, 3, or 6 months per formulation |
| Indication: Prostate cancer | Advanced (metastatic or locally advanced)Androgen deprivation therapy (ADT) backbone. |
| Indication: Endometriosis | 3.75 mg monthlyFDA-approved; typically 6-month course. |
| Indication: Central precocious puberty | Pediatric use (≥2 years) [jia-2025]Weight-based dosing per FDA label. |
| Evidence basis | Multiple Phase 3 RCTs · FDA-approved 1999 |
| Duration (prostate cancer) | Continuous or intermittent ADT protocols [preston-2024]Intermittent ADT may reduce side effects; cardiovascular risk similar to continuous. |
| Monitoring | Serum testosterone, PSA (prostate cancer), bone density, lipids, glucose |
Reconstitution
A pure mass-to-volume utility. Enter what you have in the vial; the atlas computes the volume per dose. No prescription information.
- — Hypersensitivity to triptorelin, GnRH, or GnRH agonist analogues
- — Pregnancy (Category X)
- — Active cardiovascular disease — consider GnRH antagonist alternative
- — Metastatic vertebral disease with spinal cord compression risk (flare hazard)
- — Severe urinary obstruction — may worsen during flare
- — Osteoporosis or high fracture risk (requires bone-protective therapy)
- 01Formulation selection
Choose 1-month (3.75 mg), 3-month (11.25 mg), or 6-month (22.5 mg) depot based on adherence needs and clinical context. 6-month formulation shows improved real-world adherence in Asia-Pacific cohorts.
- 02Injection site
Intramuscular — gluteal or deltoid muscle. Use 21–23G needle. Aspirate to confirm non-vascular placement. Rotate sites with repeat injections.
- 03Initial flare mitigation
For metastatic prostate cancer: co-administer antiandrogen (e.g., bicalutamide 50 mg daily) starting 1 week before first injection and continuing 2–4 weeks to prevent tumor flare.
- 04Monitoring schedule
Baseline: testosterone, PSA, bone density (DEXA), lipids, glucose. Follow-up: testosterone at 4 weeks (confirm <50 ng/dL castration), PSA monthly × 3, then quarterly. Annual DEXA for bone loss.
- 05Storage
Store vials at room temperature (20–25 °C), protect from light. Do not freeze. Reconstituted suspension should be used immediately.
- 06Intermittent ADT protocol (optional)
Some protocols use on-treatment periods (9–12 months) alternating with off-treatment intervals until PSA rises. Cardiovascular risk appears similar to continuous ADT.
Sources
of 64 rendered claims carry a resolvable citation.
- [anon-2012]Unknown 2012 — Triptorelin.
journal, 2012 - [chen-2024]Chen 2024 — Resources Utilization Assessment and Cost-Minimization Analysis of the 6-Monthly Formulation of Triptorelin in the Treatment of Prostate Cancer in China.
journal, 2024 - [friedrich-2025]Friedrich 2025 — Racial Differences in Adverse Events After Androgen Deprivation in Veterans With Prostate Cancer.
journal, 2025 - [jia-2025]Jia 2025 — Triptorelin associated adverse events evaluated using FAERS pharmacovigilance data.
journal, 2025 - [patel-2025]Patel 2025 — Safety and Efficacy of Cerebrolysin for Neurorecovery After Acute Ischemic Stroke: A Systematic Review and Meta-Analysis of 14 Randomized Controlled Trials.
journal, 2025 - [preston-2024]Preston 2024 — Risk of cardiovascular events following intermittent and continuous androgen deprivation therapy in patients with nonmetastatic prostate cancer.
journal, 2024 - [yee-2025]Yee 2025 — A 6-month sustained-release formulation of triptorelin for locally advanced or metastatic prostate cancer: a real-world experience in Asia.
journal, 2025