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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 prostate cancer, and is being studied for other conditions.

How does this drug work?

Triptorelin belongs to the general group of drugs known as hormones or hormone antagonists. It is a synthetic (man-made) version of the body’s luteinizing-hormone-releasing hormone (LHRH). This drug stops the release of testosterone from the testicles in men. This can slow or stop the growth of cells (including prostate cancer cells) that depend on testosterone. 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), gout, or infections. These conditions may require that your medicine dose, regimen, or timing be changed.
  • If you have ever been diagnosed with heart problems, especially long QT syndrome, an abnormal heart rhythm, congestive heart failure, or if you have been told you have low blood levels of potassium, calcium, or magnesium (which can affect the heart). This drug can affect the rhythm of the heart, which might lead to irregular heartbeats and can even lead to death.
  • 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. See “Precautions” section.
  • If you are breast-feeding. This drug can interfere with milk production. Also, it is not known whether this drug passes into breast milk. If it does, it could harm the baby.
  • If you want to have children in the next few month or a year. This drug can reduce fertility while you are on it and for some time after.
  • 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

Because triptorelin can affect the rhythm of the heart, be sure your doctor is aware of any drugs you take that affect heart rhythm. Examples of these drugs include:

  • Amiodorone (Cordarone, Pacerone)
  • Disopyramide (Norpace)
  • Dofetilide (Tikosyn)
  • Flecainide (Rhythmol)
  • Ibutilide (Corvert)
  • Mexiletine (Mexitil)
  • Moricizine (Ethmozine)
  • Procainamide (Procan, Pronestyl)
  • Propafenone (Tambocor)
  • Quinidine (Quinidex, Cardioquin)
  • Tocainide (Tonocard)

Beta blocker drugs slow the heart rate and can also worsen triptorelin’s effects on the heart. This class includes drugs like acebutolol (Sectral), atenolol (Tenormin), bisoprolol (Zebeta), esmolol (Brevibloc), metoprolol (Lopressor, Lopressor LA, Toprol XL), nadolol (Corgard), propranolol (Inderal), sotalol (Betapace), and timolol (Blocadren).

Clonidine (Catapres), digoxin (Lanoxin, Cardoxin, Digitek), and the calcium channel blockers diltiazem (Cardizem) and verapamil (Covera, Calan, Verelan) can also slow the heart and might cause problems while you are on triptorelin.

These drugs affect the rhythm of the heart in the same way as triptorelin and so can also increase your risk of abnormal heart rhythm if you take them during the same times you are on triptorelin.

  • Anti-psychotic drugs such as thioridazine (Mellaril), haloperidol (Haldol), mesoridazine (Serentil)
  • Antidepressants such as venlafaxine (Effexor) and amitriptyline (Elavil)
  • Certain antibiotics (e.g., erythromycin, clarithromycin, levofloxacin, ofloxacin, moxifloxacin, sparfloxacin, pentamidine)
  • Nausea medicines such as ondansetron (Zofran), dolasetron (Anzemet), granisetron (Kytril), droperidol (Inapsine), promethazine (Phenergan), and chlorpromazine (Thorazine)

This is not a complete list. Other drugs that can slow the heart rate or prolong the QT interval of the heart can increase the increase the danger of an abnormal rhythm. Check with your doctor or pharmacist to find out if other drugs you’re taking have this effect.

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 or tumor “flare.” To prevent this, doctors can give drugs that block testosterone for the first week of treatment. 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. If the flow of urine is blocked completely, this can lead to kidney failure.
  • 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, the flare can cause the cancer to press on the spinal cord and cause spinal cord compression. Early symptoms include numbness in the legs or feet, trouble urinating or moving your bowels, back pain, and weakness in the legs. If left untreated it can lead to paralysis (loss of movement). Call your doctor right away if you have any of these symptoms.
  • 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.

Your doctor will check your blood during treatment to see the drugs effect on your cancer and look for side effects. It’s important to keep all your appointments, even those just for blood tests.

This drug may raise your blood sugar (glucose) levels or even lead to diabetes. Tell your doctor if you have ever had diabetes or high blood sugar, or if you have symptoms that can be caused by high blood sugar, such as feeling thirsty all the time or having to urinate more often than normal. Your doctor may check your blood sugar levels while you are taking this drug.

Patients on triptorelin have an increased risk of heart attack and stroke. Call your doctor right away if you have pain in the chest, neck, pain, jaw or arm, shortness of breath, headache, numbness or weakness on one side of your body, or trouble talking.

Androgen deprivation therapy (such as triptorelin) can cause a change in heart rhythm called prolonged QT interval. Tell your doctor if you have ever been diagnosed with any type of heart disease, especially an abnormal heart rhythm or long QT syndrome. Your doctor may need to test your heart rhythm with an EKG and test your blood levels of certain minerals that could affect heart rhythm during treatment. Tell your doctor or nurse right away if you notice a fast or irregular heartbeat, very slow heartbeat, lightheadedness, dizziness, fainting, or shortness of breath to your doctor right away. Tell your doctor if you start to take or have any changes in heart or blood pressure medicines.

This drug has not been studied in children and is not recommended for their use.

This drug is not approved for use in women. If this drug is used during pregnancy, it may cause fetal harm. Check with your doctor about what kinds of birth control can be used with 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. (Note: some side effects listed as less common or rare become more common the longer you are on the drug.)


  • Hot flashes

Less common

  • Worsened symptoms of prostate cancer or “disease flare” (first 2 weeks)*
  • Loss of ability to have sex (impotence or erectile dysfunction)
  • Testicles getting smaller
  • Pain at injection site
  • Headache
  • Leg pain
  • Skeletal (bone) pain
  • Trouble sleeping
  • High blood sugar (including diabetes)*
  • Severe bone thinning or weakness (osteoporosis), which increases the risk of having a bone break


  • Problems urinating and kidney problems*
  • Swelling in legs, feet, and ankles
  • Decreased interest in sex
  • Breast swelling or soreness
  • Allergic reaction, with itching, skin welts, trouble breathing or swallowing*
  • Blood vessel disease (which can cause heart disease or stroke)*
  • Problems with heart rhythm, which may be serious*
  • Convulsions (seizures)
  • Pressure or bleeding in the pituitary gland, causing vomiting, headache, changes in vision, confusion, collapse, or other serious symptoms (this can occur in people who had a tumor in the pituitary, but didn’t know it before treatment)Growth of pituitary tumor (that was present before treatment but the patient didn’t know he had it)
  • Death due to diabetes, heart attack, stroke, or some other cause

*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: 09/17/2014
Last Revised: 09/17/2014