Trelstar
Trelstar (triptorelin) is a brand-name GnRH agonist administered as an intramuscular injection. It works by initially stimulating, then suppressing the pituitary gland's production of hormones that control sex hormone secretion. This medication is primarily prescribed for the palliative treatment of advanced prostate cancer and is also used for conditions such as endometriosis and uterine fibroids.
Trelstar is a GnRH agonist injection used to treat advanced prostate cancer and certain hormone-related conditions by suppressing sex hormone production.
Key facts at a glance
- RxNorm
- 905054
- Generic
- Trelstar
- Class
- brand-name
- Brands
- —
- Availability
- rx
- Lactation
- unknown
- Routes
- —
- Forms
- —
- Regions
- US, EU, CN, JP
- Monitoring
- —
This page is for informational purposes only.
Do not use this information to diagnose yourself or to replace a physician's advice. Always consult a qualified healthcare provider before starting, stopping, or changing any medication. If you believe you are experiencing a medical emergency, call your local emergency number immediately.
Trelstar is FDA-approved for the palliative treatment of advanced prostate cancer. It is also used off-label for conditions driven by sex hormones, including endometriosis, uterine fibroids, and central precocious puberty.
As a GnRH agonist, Trelstar initially causes a surge in luteinizing hormone (LH) and follicle-stimulating hormone (FSH), leading to increased sex hormone release. With continuous administration, it downregulates pituitary GnRH receptors, resulting in decreased LH and FSH secretion and subsequently reduced testosterone (in males) or estrogen (in females) production.
Trelstar is administered as a depot injection, typically every 4, 12, or 24 weeks depending on the formulation. Patients with prostate cancer may experience an initial testosterone flare in the first few weeks. Common side effects include hot flashes, decreased libido, fatigue, and injection site reactions. It should not be used by women who are pregnant or breastfeeding. Patients should be monitored for metabolic, cardiovascular, and bone density effects during prolonged treatment.
Official drug label
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This information is for educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment.
This content is for general informational and educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. Always seek the guidance of a qualified healthcare provider with any questions you have about a medical condition, and never disregard professional medical advice or delay seeking it because of something you read here.
If you think you may have a medical emergency, call your local emergency number or go to the nearest emergency department immediately.
Medically reviewed by WellAlly Editorial Team Last reviewed August 25, 2026. · Read our editorial policy