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(trip-toe-rel-in, trip-toe-rel-in)

Trade/other name(s): Trelstar Depot, Trelstar LA

Why would this drug be used?

Triptorelin is used to treat advanced prostate cancer, and is being studied for other conditions.

How does this drug work?

Triptorelin belongs to the general group of drugs known as hormone antagonists. It is a synthetic (man-made) version of the body’s luteinizing-hormone-releasing hormone (LHRH). It blocks the release of testosterone in men, which can stop the growth of cancer cells that depend on these hormones. If the medicine is stopped, hormone levels return to normal.

Before taking this medicine

Tell your doctor…

  • If you are allergic to anything, including medicines, dyes, additives, or foods.
  • If you have ever had diabetes, heart disease, high blood pressure, high cholesterol, heart attack, or stroke. Also tell your doctor if you have ever smoked. Your doctor may watch you more closely for heart and blood vessel problems while you take this drug.
  • If you have any other medical conditions such as kidney disease, liver disease (including hepatitis), congestive heart failure, gout, or infections. These conditions may require that your medicine dose, regimen, or timing be changed.
  • If you or others in your family have weakened bones (osteoporosis), if you have ever been a smoker or heavy user of alcohol, or if you have taken steroids or medicines to prevent seizures, which can cause bone loss. Triptorelin can speed up loss of bone minerals, so your doctor may need to watch you for this.
  • If you have trouble passing your urine due to enlarged prostate or other blockage.
  • If you are pregnant, trying to get pregnant, or if there is any chance of pregnancy. There may be an increased risk of harm to the fetus if a woman takes this drug during pregnancy.
  • If you are breast-feeding. It is not known whether this drug passes into breast milk. If it does, it could harm the baby.
  • If you think you might want to have children in the future. This drug may reduce fertility. Talk with your doctor about the possible risk with this drug and the options that may preserve your ability to have children.
  • About any other prescription or over-the-counter medicines you are taking, including vitamins and herbs. In fact, keeping a written list of each of these medicines (including the doses of each and when you take them) with you in case of emergency may help prevent complications if you get sick.

Interactions with other drugs

No serious interactions are known at this time. But this does not necessarily mean that none exist. Check with your doctor, nurse, or pharmacist about other medicines, vitamins, herbs, and supplements, and whether alcohol can cause problems with this medicine.

Interactions with foods

No serious interactions with food are known at this time. Check with your doctor, nurse, or pharmacist about whether foods may be a problem.

Tell all the doctors, dentists, nurses, and pharmacists you visit that you are taking this drug.

How is this drug taken or given?

Triptorelin is injected into the muscle of the buttocks, either once a month, once every 3 months, or once every 6 months. The medicine is slowly released over time. The dosing is the same for all adults.


Triptorelin may briefly increase testosterone in men when the drug is first started. This can cause the symptoms of prostate cancer to get worse for about a week and is called a “disease flare.” These symptoms usually improve after a week or two, but sometimes extra treatment is needed:

  • The prostate gland may enlarge, and you may have blood in your urine, painful urination, or trouble passing urine. Call your doctor if you have these symptoms.
  • Bone pain may also worsen. Call your doctor or nurse right away if your pain medicine is not stopping the pain during this time. They will help you get the right dose or drug for the time that the pain has increased.
  • If prostate cancer has spread to the bones of the spine, leg weakness may also occur. To prevent this, most doctors give drugs that block testosterone for the first week of treatment. Call your doctor right away if you develop numbness or tingling of the fingers/hands or toes/feet, weakness in the legs, or trouble urinating or moving your bowels.
  • Tell your doctor right away if you have flare symptoms that last longer than 2 weeks.

This drug can cause allergic reactions in some people. Call your doctor right away if you develop skin welts, itching, swelling in the face, mouth, or throat, or other possible signs of an allergic reaction. If you are allergic to other LHRH agonists, such as leuprolide (Lupron or Eligard), histrelin (Vantas), goserelin (Zoladex), you shouldn’t take triptorelin.

It is important to keep taking this drug, even if you feel well. If you are bothered by side effects, talk to your doctor or nurse to find out if the problems are serious. Many side effects can be managed with help from your doctor.

Your doctor may watch you for signs of diabetes and cardiovascular disease (which can result in heart attacks and strokes) while you are on this medicine.

Possible side effects

You will probably not have most of the following side effects, but if you have any talk to your doctor or nurse. They can help you understand the side effects and cope with them.


  • Hot flashes
  • Decreased interest in sex

Less common

  • Worsened symptoms of prostate cancer or “disease flare” (first 2 weeks)*
  • Loss of ability to have sex (impotence)
  • Pain at injection site
  • Headache
  • Leg pain
  • Skeletal (bone) pain
  • Vomiting
  • Trouble sleeping


  • Headache
  • Swelling in legs, feet, and ankles
  • Osteoporosis or bone thinning
  • Allergic reaction, with itching, skin welts, trouble breathing or swallowing*
  • Diabetes*
  • Blood vessel disease (heart disease or stroke)*
  • Sudden death due to heart attack or stroke
  • Convulsions (seizures)

*See the “Precautions” section for more detailed information.

There are other side effects not listed above that can also occur in some patients. Tell your doctor or nurse if you develop these or any other problems.

FDA approval

Yes – first approved in 2000.

Disclaimer: This information does not cover all possible uses, actions, precautions, side effects, or interactions. It is not intended as medical advice, and should not be relied upon as a substitute for talking with your doctor, who is familiar with your medical needs.

Last Medical Review: 04/30/2013
Last Revised: 04/30/2013