Triptorelin (Trelstar LA® and Trelstar Depot®)

Author: Marisa Healy, BSN, RN
Last Reviewed: December 04, 2023

Pronounce: TRIP-toe-REL-in

Classification: Luteinizing Hormone Releasing Hormone (LHRH) Agonist

About: Triptorelin (Trelstar LA® and Trelstar Depot®)

Triptorelin is a type of Luteinizing Hormone-Releasing (LHRH) agonist. 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. A hormone called luteinizing hormone (LH), which is produced by the pituitary gland stimulates the production of testosterone by the testicles. 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.

How to Take Triptorelin

Triptorelin is given as an intramuscular (IM, into the muscle) injection at your healthcare provider’s office. Triptorelin is given once every 4, 12, or 24 weeks, depending on the dose. It is usually injected into the buttock, rotating the injection site with each injection.

Possible Side Effects of Triptorelin

There are a number of things you can do to manage the side effects of triptorelin. Talk to your care team about these recommendations. They can help you decide what will work best for you. These are some of the most common or important 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 related to the cancer to worsen. Your healthcare team can tell you what to look for in your particular case and the treatment necessary. The symptoms typically diminish 3 to 4 weeks after your injection was given.

Hot Flashes

There are a few things you can do to help with hot flashes. Several medications have been shown to help with symptoms, including clonidine (a blood pressure medication), low doses of certain antidepressants (such as venlafaxine and fluoxetine), and gabapentin. Talk to your healthcare team about these prescription products to determine if they are right for you.

Non-medical recommendations include:

  • Keep well-hydrated with eight glasses of water daily.
  • Drink ice water or apply an ice pack at the onset of a hot flash.
  • Wear cotton or lightweight, breathable fabrics and dress in layers so you can adjust as needed.
  • Exercise on a regular basis.
  • Try practicing meditation or relaxation exercises to manage stress, which can be a trigger.
  • Avoid triggers such as warm rooms, spicy foods, caffeinated beverages, and alcohol.

Weakening of the Bones (Osteoporosis)

Men who take hormone therapy for extended periods of time are at risk for bone thinning (osteoporosis). You may be advised to take calcium and vitamin D supplements to help prevent bone loss. Weight-bearing exercise and a healthy diet rich in calcium and vitamin D can also help protect your bone health. You may have a bone density scan (DEXA scan) to assess your bone health. If your physician determines that you are at high risk of developing osteoporosis, they may recommend additional treatment with a type of medication called a bisphosphonate to help strengthen the bones.

Impotence and Loss of Sex Drive (Libido)

These side effects typically go away once the medication is stopped. You may notice a lack of ability to have and maintain an erection, loss of sex drive, or a decrease in the size of the testicles. Talk to your healthcare team about options to treat these symptoms.

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.


Fatigue is very common during cancer treatment and is an overwhelming feeling of exhaustion that is not usually relieved by rest. While on cancer treatment, and for a period after, 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 for helpful tips on dealing with this side effect.

Less common, but important side effects can include:

  • Metabolic Syndrome: This medication can lead to metabolic changes, such as high blood sugar, diabetes, and high lipids (hyperlipidemia). Triptorelin can also cause non-alcoholic fatty liver disease, including cirrhosis.
  • Heart Problems, Heart Attack, and Stroke: Triptorelin can increase the risk of stroke and heart attack. If you experience symptoms of these problems, you should contact your healthcare provider immediately or go to an emergency room. Symptoms can include swelling, redness or pain in an extremity, chest pain or pressure, pain in your arm, back, neck, or jaw, shortness of breath, numbness or weakness on one side of the body, trouble talking, confusion, or mental status changes. This medication can cause an abnormal heart rhythm called QT prolongation. Notify your healthcare provider if you feel abnormal heartbeats or if you feel dizzy or faint.
  • Allergic Reactions: There have been rare reports of serious allergic reactions. Signs of an allergic reaction including chest pain, rash, flushing, itching, shortness of breath, fever, and chills should be reported to your provider immediately. Patients with an allergy to other LHRH agonists should not use triptorelin.

Reproductive Concerns

Exposure of an unborn child to this medication could cause birth defects, so you should not father a child while on this medication. Effective birth control is necessary during treatment. Even if you believe you are not producing sperm, you could still be fertile.


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