Triptorelin (Trelstar LA® and Trelstar Depot®)

Last Modified: September 13, 2012

Pronounced: TRIP-toe-REL-in
Classification: Luteinizing Hormone Releasing Hormone (LHRH) Agonist

About Triptorelin

Most prostate cancers need supplies of the male hormone testosterone to grow. Testosterone is an androgen produced by the testes and adrenal glands. The production of testosterone can be stopped by surgically removing the testicles or through medication therapy. Production of testosterone by the testicles is stimulated by a hormone called luteinizing hormone (LH), which is produced by the pituitary gland. Agonists of the LH releasing hormone (i.e. LHRH agonists) stop the production of luteinizing hormone by the pituitary gland. This reduces the production of testosterone in men. The cancer cells may then grow more slowly or stop growing altogether. Triptorelin is a type of LHRH agonist.

How to Take Triptorelin

Triptorelin is given as an intramuscular (into the muscle) injection at your doctor's office. Triporelin comes in two formulations:

  • Trelstar Depot® is given as a monthly injection (every 4 weeks). The dosage is 3.75mg per treatment.
  • Trelstar LA® is given as an injection every 84 days (12 weeks). The dosage is 11.25mg per treatment.

Possible Side Effects of Triptorelin

There are a number of things you can do to manage the side effects of Triptorelin. Talk to your doctor or nurse about these recommendations. They can help you decide what will work best for you. These are some of the most common side effects:

Initial Tumor Flare

When starting an LHRH agonist, the body initially has a temporary increase in testosterone levels. This “flare” can lead to a temporary increase in the tumor size, causing symptoms to worsen. Your healthcare team can tell you what to look for in your particular case and what to do about it.

Hot Flashes

Most men find that hot flashes decrease after a period of time on the medication. Several medications have been studied, including clonidine (a blood pressure medication) and low dose antidepressants (such as venlafaxine and Prozac). Although most studies were done in women with breast cancer, recent research has shown they may be effective in men being treated for prostate cancer. Non-medical recommendations include: keeping well hydrated with 8 glasses of water daily, wearing all-natural fiber clothes, dressing in layers, exercising on a regular basis (generally walking exercise is best), practicing relaxation exercises, and avoiding triggers such as warm rooms, spicy foods, caffeinated beverages, nicotine and alcohol.


The lack of testosterone while taking LHRH agonists can lead to a weakening of the bones. This puts you at higher risk of bone fractures. Bone health should be monitored with bone density scans and treatment should be started if osteoporosis develops. Research has shown that weight-bearing exercise can help decrease the risk of developing osteoporosis.

Impotence and Loss of Sex Drive (Libido)

These side effects typically go away once the medication is stopped. Talk to your healthcare team about options to treat impotence.

Breast Tenderness or Increase in Breast Tissue

An increase in breast tissue (gynecomastia) or breast tenderness may develop. Your healthcare team can suggest medications to relieve the tenderness. In rare cases, radiation can be given to relieve the tenderness.

Bone Pain or Headache

Your doctor or nurse can recommend medication and other strategies to relieve bone pain or headaches.


While on cancer treatment you may need to adjust your schedule to manage fatigue. Plan times to rest during the day and conserve energy for more important activities. Exercise can help combat fatigue; a simple daily walk with a friend can help. Talk to your healthcare team and see OncoLink’s section on fatigue for helpful tips on dealing with this side effect.

Other Side Effects

Leg pain or swelling in the legs. There have been rare reports of serious allergic reactions. Patients with an allergy to other LHRH agonists should not use triptorelin.


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