Trelstar is a brand-name prescription drug that's used for palliative treatment of advanced prostate cancer in adult males. With palliative treatment, symptoms of your condition are reduced to help improve your quality of life. Trelstar isn't meant to cure prostate cancer.

Trelstar contains the drug triptorelin, which belongs to a class of medications called gonadotropin-releasing hormone (GnRH) agonists. It works by stopping your body from making the hormone testosterone, which helps to stop the growth and spread of prostate cancer. This in turn helps to reduce symptoms of the condition, such as bone pain and trouble urinating.

Trelstar is given as an intramuscular injection (an injection into your muscle) by a healthcare provider. This medication comes in three strengths: 3.75 mg, 11.25 mg, and 22.5 mg.

Effectiveness

Trelstar was evaluated for its effectiveness in three separate clinical studies, which included 428 men with advanced prostate cancer. In these studies, the men received three different doses of Trelstar as follows:

  • Those receiving 3.75 mg of Trelstar were given the drug every 4 weeks.
  • Those receiving 11.25 mg of Trelstar were given the drug every 12 weeks.
  • Those receiving 22.5 mg of Trelstar were given the drug every 24 weeks.

These studies looked at how many men reached and stayed in "medical castration" with treatment.

With medical castration, a person's blood testosterone level is less than 50 ng/dL. Low testosterone levels help show that prostate cancer is not getting worse. A testosterone level of at least 300 ng/dL is typically considered normal for men. However, a level below 50 ng/dL is the goal when treating prostate cancer.

These clinical studies of Trelstar lasted between 253 days and 337 days. On day 29 of the studies, 91.2% to 97.7% of the men who took Trelstar reached medical castration. By the end of each study, 93.3% to 96.2% of the men who took Trelstar remained in medical castration.

Trelstar is available only as a brand-name medication. It's not currently available in generic form. (A generic drug is an exact copy of a brand-name medication.)

Trelstar contains the active drug triptorelin. It belongs to a class of drugs called gonadotropin-releasing hormone (GnRH) agonists.

Your Trelstar dosage will depend on the dosing schedule that you and your doctor determine is best for you.

The following information describes dosages that are commonly used or recommended. However, be sure to take the dosage your doctor prescribes for you. Your doctor will determine the best dosage to fit your needs.

Drug forms and strengths

Trelstar comes as a powder that's mixed with liquid and given as an intramuscular injection (an injection into your muscle). You'll receive Trelstar injections from your healthcare provider. Trelstar comes in three strengths: 3.75 mg, 11.25 mg, and 22.5 mg.

Each strength of Trelstar is given according to a different dosing schedule. These dosing schedules are described below.

Dosage for advanced prostate cancer

For advanced prostate cancer, Trelstar is given according to the following dosing schedule:

  • injections of 3.75 mg are given every 4 weeks (about once each month)
  • injections of 11.25 mg are given every 12 weeks (about once every 3 months)
  • injections of 22.5 mg are given every 24 weeks (about once every 6 months)

What if I miss a dose?

Because Trelstar is administered at your doctor's office by a healthcare provider, they'll be sure to schedule your appointments when you're due for an injection. If you happen to miss an appointment for your injection, call your doctor's office right away. The medical staff will help you reschedule your appointment.

To help make sure that you don't miss an appointment, try setting a reminder on your phone or leaving a note on your calendar.

Will I need to use this drug long term?

Trelstar is meant to be used as a long-term treatment to help reduce prostate cancer symptoms and improve your quality of life. If you and your doctor determine that Trelstar is safe and effective for you, you'll likely take it long term.

Trelstar can cause mild or serious side effects. The following lists contain some of the key side effects that may occur while taking Trelstar. These lists do not include all possible side effects.

For more information on the possible side effects of Trelstar, talk with your doctor or pharmacist. They can give you tips on how to deal with any side effects that may be bothersome.

Note: The Food and Drug Administration (FDA) tracks side effects of drugs they have approved. If you would like to report to the FDA a side effect you've had with Trelstar, you can do so through MedWatch.

More common side effects

The more common side effects of Trelstar can include:

Most of these side effects may go away within a few days or a couple of weeks. If they're more severe or don't go away, talk with your doctor or pharmacist.

Serious side effects

Serious side effects from Trelstar aren't common, but they can occur. Call your doctor right away if you have serious side effects. Call 911 if your symptoms feel life threatening or if you think you're having a medical emergency.

Serious side effects and their symptoms can include:

  • Cancer spreading to or becoming worse in your spinal cord. This can cause paralysis and problems in your kidneys, such as blockage. Symptoms of cancer spreading or worsening may include:
    • weakness
    • not being able to move certain parts of your body
    • being unable to urinate or having trouble urinating
    • blood in your urine
  • Problems with your heart's electrical system, such as long QT syndrome. Symptoms can include:
    • unexplained fainting
    • seizures
    • gasping while sleeping
  • Cardiovascular problems, such as heart attack, stroke, or sudden death. Symptoms can include:
    • pressure, tightness, or pain in your chest
    • feeling lightheaded or dizzy
    • sudden numbness or weakness in your face, arm, or leg (on one side of your body)
    • sudden confusion
    • trouble speaking
    • sudden trouble walking
  • High blood sugar level, which may lead to diabetes. Symptoms can include:
    • being more thirsty than usual
    • needing to urinate more often than usual
    • headaches
    • trouble concentrating

Other serious side effects, which are explained below in "Side effect details," include:

  • severe allergic reaction
  • short-term increase in your testosterone level (called a tumor flare)

Side effect details

You may wonder how often certain side effects occur with this drug. Here's some detail on several of the side effects this drug may cause.

Allergic reaction

As with most drugs, some people can have an allergic reaction after taking Trelstar. But it's not known for sure how many people taking Trelstar have had an allergic reaction to the drug.

Symptoms of a mild allergic reaction can include:

  • skin rash
  • itchiness
  • flushing (warmth and redness in your skin)

A more severe allergic reaction is rare but possible. Symptoms of a severe allergic reaction can include:

  • swelling under your skin, typically in your eyelids, lips, hands, or feet
  • swelling of your tongue, mouth, or throat
  • trouble breathing

Call your doctor right away if you have a severe allergic reaction to Trelstar. Call 911 if your symptoms feel life threatening or if you think you're having a medical emergency.

Hot flashes

You may experience hot flashes (also called hot flushes) when you're taking Trelstar. This side effect is likely due to hormonal changes in your body caused by the drug. In clinical studies, 58.6% to 73% of people taking Trelstar had a hot flash. However, hot flashes occurred in fewer men taking the lowest dose (3.75 mg) of Trelstar than in men taking higher doses.

If you're bothered by hot flashes during Trelstar treatment, talk with your doctor. They can recommend ways to help ease your discomfort.

Bone pain

Bone pain (sometimes called skeletal pain) is a possible side effect of Trelstar. In clinical studies, 12.1% to 13.2% of men taking Trelstar had bone pain.

This side effect may also be caused by tumor flare, which is an initial, short-term increase in your testosterone level. (Tumor flare is possible if you take Trelstar or other drugs similar to it.) If tumor flare is causing your bone pain, the pain should go away after your testosterone level goes back down. This will generally happen after you've been using the drug for a few weeks.

If you have bone pain while you're taking Trelstar, talk with your doctor. They can recommend ways to help relieve your pain.

Tumor flare

You may experience a tumor flare in the first few weeks of treatment with Trelstar. Tumor flare is a short-term increase in your testosterone level. It's a possible side effect with all gonadotropin-releasing hormone (GnRH) agonists, including Trelstar.

Symptoms of tumor flare can include:

  • bone pain
  • nerve pain
  • blood in your urine
  • trouble urinating
  • difficulty moving certain body parts

If you have blood in your urine or difficulty moving certain body parts, call your doctor right away. These symptoms can indicate serious medical conditions that need to be treated right away. However, a tumor flare doesn't mean that your cancer is spreading or getting worse.

To help you avoid tumor flare during treatment, your doctor may prescribe other medications for you to take with Trelstar. These other medications are called anti-androgens.

If you have concerns about tumor flare while you're using Trelstar, talk with your doctor.

In addition to Trelstar, other drugs can also be used for palliative treatment of advanced prostate cancer. Some may be a better fit for you than others. If you're interested in finding an alternative to Trelstar, talk with your doctor. They can tell you about other medications that may work well for you.

Examples of other drugs that may be used for palliative treatment of advanced prostate cancer include:

  • leuprolide (Eligard, Lupron Depot)
  • goserelin (Zoladex)
  • degarelix (Firmagon)
  • histrelin (Vantas)

Note: Some of the drugs listed above may be used off-label for this purpose. Off-label use is when a drug that's approved to treat one condition is used to treat a different condition.

You may wonder how Trelstar compares to other medications that are prescribed for similar uses. Here we look at how Trelstar and Lupron Depot are alike and different.

Ingredients

Trelstar and Lupron Depot both contain drugs that belong to a class of medications called gonadotropin-releasing hormone (GnRH) agonists. Trelstar contains the drug triptorelin, while Lupron Depot contains the drug leuprolide.

Uses

Trelstar and Lupron Depot are both approved by the Food and Drug Administration (FDA) for palliative treatment of advanced prostate cancer in adult males. With palliative treatment, symptoms of your condition are reduced to help improve your quality of life. Trelstar and Lupron Depot aren't meant to cure prostate cancer.

Lupron Depot is also FDA-approved to treat endometriosis and fibroids. For these conditions, Lupron Depot is given at a different dosage than the dosage used for prostate cancer.

Drug forms and administration

Trelstar comes as a powder that's mixed with liquid and given as an intramuscular injection (an injection into your muscle) by your healthcare provider. Trelstar comes in three strengths, which are each given according to a different dosing schedule. This drug is generally given once every 4, 12, or 24 weeks.

Lupron Depot also comes as a powder that's mixed with liquid and given by intramuscular injection by your healthcare provider. Lupron comes in four strengths, which are each given according to a different dosing schedule. The drug is usually given once every 4, 12, 16, or 24 weeks.

Side effects and risks

Trelstar and Lupron Depot both contain gonadotropin-releasing hormone (GnRH) agonists. Therefore, these medications can cause very similar side effects. Below are examples of these side effects.

More common side effects

These lists contain examples of more common side effects that can occur with Trelstar, with Lupron Depot, or with both drugs (when taken individually).

  • Can occur with Trelstar:
  • Can occur with Lupron Depot:
    • redness and swelling around your injection site
    • sweating
    • trouble urinating
    • upper respiratory infection, such as common cold
    • joint pain
    • intestinal problems, including bleeding in your stomach or intestines
  • Can occur with both Trelstar and Lupron Depot:
    • hot flashes
    • pain at your injection site
    • pain all over your body
    • swelling in your legs
    • reduced size of your testicles
    • headache
    • tiredness

Serious side effects

These lists contain examples of serious side effects that can occur with Trelstar, with Lupron, or with both drugs (when taken individually).

  • Can occur with Trelstar:
    • cancer spreading to or becoming worse in your spinal cord, which can cause paralysis and problems in your kidneys, such as blockage
  • Can occur with Lupron Depot:
    • seizures or convulsions
  • Can occur with both Trelstar and Lupron Depot:

Effectiveness

Both Trelstar and Lupron Depot are used as palliative treatment for advanced prostate cancer.

The use of Trelstar and Lupron Depot in treating advanced prostate cancer has been directly compared in a clinical study. In this 9-month study, 125 men with advanced prostate cancer were split into three groups. The men were given one of the following: Trelstar, Lupron Depot, or another cancer drug called goserelin (Zoladex).

The men's testosterone levels were followed during the study to evaluate how well they responded to treatment. Low testosterone levels help show that prostate cancer is not getting worse. A testosterone level of at least 300 ng/dL is typically considered normal for men. However, a level below 50 ng/dL is the goal when treating prostate cancer.

Of the men treated with Trelstar, 93.2% achieved a testosterone level of less than 10 ng/dL. In comparison, 86.4% of men treated with Lupron Depot had the same result. (Of those taking goserelin, 54.2% had this same result.)

Costs

Trelstar and Lupron Depot are both brand-name drugs. There are currently no generic forms of either drug. Brand-name medications usually cost more than generics.

According to estimates on WellRx.com, Lupron Depot generally costs significantly more than Trelstar. The actual price you'll pay for either drug depends on your insurance plan, your location, and the pharmacy you use.

Like Lupron, which was described above, the drug Zoladex has uses similar to those of Trelstar. Here's a comparison of how Trelstar and Zoladex are alike and different.

Ingredients

Trelstar and Zoladex both contain drugs that belong to the class of medications called gonadotropin-releasing hormone (GnRH) agonists. Trelstar contains the drug triptorelin, while Zoladex contains the drug goserelin.

Uses

Both Trelstar and Zoladex are approved by the Food and Drug Administration (FDA) for palliative treatment of advanced prostate cancer in adult men. With palliative treatment, symptoms of your condition are reduced to help improve your quality of life. Trelstar and Zoladex aren't meant to cure prostate cancer.

Zoladex is also FDA-approved to treat:

Drug forms and administration

Trelstar comes as a powder that's mixed with liquid and given as an intramuscular injection (an injection into your muscle) by your healthcare provider. Trelstar comes in three different strengths. Each strength is given according to a different dosing schedule. This drug is generally given once every 4, 12, or 24 weeks.

Zoladex comes as an implant that's placed under the skin of your belly by your healthcare provider. For advanced prostate cancer treatment, Zoladex is placed once every 28 days.

Side effects and risks

Trelstar and Zoladex both contain drugs that belong to a class called gonadotropin-releasing hormone (GnRH) agonists. Therefore, these medications can cause very similar side effects. Below are examples of these side effects.

More common side effects

These lists contain examples of more common side effects that can occur with Trelstar, with Zoladex, or with both drugs (when taken individually).

Serious side effects

These lists contain examples of serious side effects that can occur with Trelstar, with Zoladex, or with both drugs (when taken individually).

  • Can occur with Trelstar:
    • few unique serious side effects
  • Can occur with Zoladex:
    • high calcium level in your blood
    • serious injury at the site of your injection
  • Can occur with both Trelstar and Zoladex:
    • cardiovascular problems, such as heart attack, stroke, or sudden death
    • high blood sugar level, which lead to diabetes
    • short-term increase in your testosterone level (called a tumor flare)
    • cancer spreading to or becoming worse in your spinal cord, which can cause paralysis and problems in your kidneys, such as blockage
    • problems with your heart's electrical activity, such as long QT syndrome
    • severe allergic reaction

Effectiveness

Both Trelstar and Zoladex are used as palliative treatment for advanced prostate cancer.

The use of Trelstar and Zoladex in treating advanced prostate cancer has been directly compared in a clinical study. In this 9-month study, 125 men with advanced prostate cancer were split into three groups. The men were given one of the following: Trelstar, Zoladex, or another cancer drug called leuprolide (Lupron Depot).

The men's testosterone levels were followed during the study to evaluate how well they responded to treatment. Low testosterone levels help show that prostate cancer is not getting worse. A testosterone level of at least 300 ng/dL is typically considered normal for men. However, a level below 50 ng/dL is the goal when treating prostate cancer.

Over 9 months of treatment, 93.2% of the men treated with Trelstar reached a testosterone level of less than 10 ng/dL. In comparison, 54.2% of the men treated with Zoladex had the same result. (Of those taking leuprolide, 86.4% had this same result.)

Costs

Trelstar and Zoladex are both brand-name drugs. There are currently no generic forms of either drug. Brand-name medications usually cost more than generics.

According to estimates on WellRx.com, Trelstar generally costs significantly more than Zoladex. The actual price you'll pay for either drug depends on your insurance plan, your location, and the pharmacy you use.

The Food and Drug Administration (FDA) approves prescription drugs such as Trelstar to treat certain conditions. Trelstar is sometimes also used off-label for other conditions. Off-label use is when a drug that's approved to treat one condition is used to treat a different condition.

Trelstar for advanced prostate cancer

Trelstar is FDA-approved for palliative treatment of advanced prostate cancer in adult males. With palliative treatment, symptoms of your condition are reduced to help improve your quality of life. Trelstar isn't meant to cure prostate cancer.

With advanced prostate cancer, the cancer has spread from your prostate to other areas of your body. This is also called metastatic prostate cancer. Prostate cancer commonly spreads to other organs in your pelvis and your bones. This can lead to bothersome symptoms, such as urinary and bowel issues, and pain and discomfort in the areas affected by the cancer.

Trelstar contains the drug triptorelin. It belongs to a class of medications called gonadotropin-releasing hormone (GnRH) agonists. This class of drugs falls into a larger category of prostate cancer drugs called hormone therapy.

Hormone therapy works by stopping your body from making the hormone testosterone, or by blocking the activity of testosterone. These actions help to stop the growth and spread of prostate cancer in your body. This in turn helps to relieve your symptoms of the condition.

Effectiveness for advanced prostate cancer

Trelstar was evaluated for its effectiveness in three separate clinical studies, which included 428 men with advanced prostate cancer. In these studies, the men received three different doses of Trelstar as follows:

  • those receiving 3.75 mg of Trelstar were given the drug every 4 weeks
  • those receiving 11.25 mg of Trelstar were given the drug every 12 weeks
  • those receiving 22.5 mg of Trelstar were given the drug every 24 weeks

These studies looked at how many men reached and stayed in "medical castration" with treatment.

With medical castration, your blood testosterone level is less than 50 ng/dL. Low testosterone levels help show that your prostate cancer is not getting worse. A testosterone level of at least 300 ng/dL is typically considered normal for men. However, a level below 50 ng/dL is the goal when treating prostate cancer.

These clinical studies of Trelstar lasted between 253 days and 337 days. On day 29 of the studies, 91.2% to 97.7% of the men who took Trelstar reached medical castration. By the end of each study, 93.3% to 96.2% of the men who took Trelstar remained in medical castration.

Off-label uses for Trelstar

In addition to the use listed above, Trelstar may be used off-label. Off-label drug use is when a drug that's approved for one use is used for a different one that's not approved.

Trelstar for endometriosis

Trelstar isn't approved to treat endometriosis, but sometimes it's used off-label for this condition. With endometriosis, the tissue that lines your uterus is also found in other areas in your body. Women who have endometriosis may have painful periods, pain with sexual intercourse, or trouble becoming pregnant.

Gonadotropin-releasing hormone (GnRH) agonists, such as Trelstar, work to lower estrogen levels and put women into a temporary menopause-like state. This method of treatment has been found helpful in easing endometriosis symptoms.

In fact, Trelstar is currently being studied for this use in women with endometriosis who are planning to undergo in vitro fertilization (IVF) to become pregnant. However, the results of this study aren't yet available.

If you'd like to know more about using Trelstar to treat endometriosis, talk with your doctor.

Trelstar for breast cancer

Trelstar isn't approved to treat breast cancer, but sometimes it's used off-label for this condition.

Gonadotropin-releasing hormone (GnRH) agonists, such as Trelstar, are often used in combination with breast cancer drugs to block estrogen from reaching breast cancer cells. Because estrogen makes some cancer tumors grow, this action helps to slow the growth and spread of breast cancer.

Trelstar has been studied in combination with the cancer drug tamoxifen. One study looked at 333 women who hadn't yet reached menopause and who had intermediate-risk hormone-receptor positive breast cancer. During this study, this combination of drugs was shown to be safe and effective for treating their condition.

If you're interested in using Trelstar for breast cancer treatment, talk with your doctor.

Trelstar can be used alone or with other drugs. Sometimes other drugs called anti-androgens are given with Trelstar in order to lower your risk of tumor flare. (Tumor flare is a short-term increase in your testosterone level.)

Tumor flare can happen for a few weeks after you've first started Trelstar or other similar drugs. Lowering your risk of tumor flare helps to reduce the possible symptoms associated with the condition, such as paralysis and bone pain.

Anti-androgens, which block the activity of testosterone in your body, can be taken in combination with Trelstar. Or they can be taken before you've started Trelstar. Examples of anti-androgen medications include:

  • bicalutamide (Casodex)
  • nilutamide (Nilandron)
  • flutamide

Other drugs can also be used to lower your risk of tumor flare by blocking your body from making testosterone. These drugs are finasteride (Proscar) and dutasteride (Avodart). They're used in a treatment method called triple androgen blockade. With this method, one of these drugs is used in combination with both an anti-androgen drug and Trelstar.

Note: Some of the drugs mentioned above are used off-label for these purposes. Off-label use is when a drug that's approved to treat one condition is used to treat a different condition.

Here are answers to some frequently asked questions about Trelstar.

Is Trelstar chemotherapy?

No, Trelstar isn't a form of chemotherapy (traditional drugs used to treat cancer). It works differently in your body than chemotherapy does.

Chemotherapy affects cells in your body that are rapidly dividing (making more cells). Since cancer cells typically divide rapidly, they're affected by chemotherapy. But some healthy cells in your body also divide rapidly, which means that these healthy cells can also be affected by chemotherapy.

Trelstar, on the other hand, is a type of hormone therapy. It belongs to a class of drugs called gonadotropin-releasing hormone (GnRH) agonists. It works by stopping your body from making testosterone. This action helps to stop the growth and spread of prostate cancer in your body.

Will Trelstar lower my testosterone level?

Yes, it will. One of the primary goals of prostate cancer treatment is to lower people's testosterone level. This is because prostate cancer grows and spreads when it's exposed to testosterone. When testosterone levels are reduced, prostate cancer tumors may shrink in size or even go away completely. This in turn helps to relieve symptoms of the condition.

In clinical studies, Trelstar was found effective in lowering testosterone levels in people with advanced prostate cancer. See the section "Trelstar Uses" above for more details.

Can Trelstar cause sexual problems?

It might, although this side effect isn't common. In clinical studies, 2.3% of men taking Trelstar (11.25 mg) had a decrease in their sexual desire. Also, 10% of men taking Trelstar (22.5 mg) had erectile dysfunction (inability to have or keep an erection).

If you're having sexual problems while you're using Trelstar, talk with your doctor. They can discuss treatment options that may help improve your symptoms.

Does Trelstar cure prostate cancer?

No, treatment with Trelstar alone won't cure prostate cancer. But Trelstar can reduce the size of your cancer tumors and stop them from growing and spreading in your body. Trelstar is meant to be used as a palliative treatment. This means that it's used to improve your quality of life and reduce your symptoms of prostate cancer rather than to cure the condition.

If you'd like to know more about treatment options for curing prostate cancer, talk with your doctor.

It's not known whether Trelstar and alcohol interact with each other.

However, both Trelstar and alcohol are partly metabolized (broken down) inside your liver. Drinking too much alcohol while you're taking Trelstar may prevent your liver from breaking down Trelstar. This could increase your risk of side effects from Trelstar.

Talk with your doctor about how much alcohol is safe for you to drink while you're using Trelstar.

It's not known if Trelstar interacts with other medications or supplements.

Different interactions can cause different effects. For instance, some interactions can interfere with how well a drug works. Other interactions can increase side effects or make them more severe.

Trelstar and other medications

There haven't been any studies done to look at whether Trelstar can interact with other medications. But it's possible that Trelstar may interact with certain medications.

Before taking Trelstar, talk with your doctor and pharmacist. Tell them about all prescription, over-the-counter, and other drugs you take. Sharing this information can help you avoid potential interactions.

If you have questions about drug interactions that may affect you, ask your doctor or pharmacist.

Trelstar and herbs and supplements

There aren't any herbs or supplements that have been specifically reported to interact with Trelstar. However, you should still check with your doctor or pharmacist before using vitamins, herbs, or supplements while taking Trelstar.

Trelstar and lab tests

If you take Trelstar over a long period of time, you may have reduced levels of certain hormones in your body. If you have any lab tests that look for these hormones, the results of the tests may be incorrect during Trelstar treatment.

It's recommended that you wait until after you've finished Trelstar treatment before you have these hormone tests. This way, the results are less likely to be incorrect.

For more information about which lab tests will be affected by Trelstar, talk with your doctor.

As with all medications, the cost of Trelstar can vary. To find current prices for Trelstar in your area, check out WellRx.com. The cost you find on WellRx.com is what you may pay without insurance. The actual price you'll pay depends on your insurance plan, your location, and the pharmacy you use.

Your insurance plan may require you to get prior authorization before approving coverage for Trelstar. This means that your doctor and insurance company will need to communicate about your prescription before the insurance company will cover the drug. The insurance company will review the request and let you and your doctor know if your plan will cover Trelstar.

If you're not sure if you'll need to get prior authorization for Trelstar, contact your insurance company.

Financial and insurance assistance

If you need financial support to pay for Trelstar, or if you need help understanding your insurance coverage, help is available.

Allergan, Inc., the manufacturer of Trelstar, offers help through its Trelstar Patient Assistance Program. For more information and to find out if you're eligible for support, call the Trelstar Support Line at 800-433-8871, and choose option 2. You can also view this online brochure (see the section "Different Programs for Different Patient Needs").

Trelstar will be given as an intramuscular injection (an injection into your muscle). It's injected into either one of your gluteus (buttock) muscles. You'll receive your injections from a healthcare provider in a medical office.

When it's given

Depending on the strength of Trelstar that your doctor prescribes for you, the drug is given once every 4, 12, or 24 weeks. You'll go to your doctor's office to receive your injections.

To help make sure that you don't miss an appointment for your injection, try setting a reminder on your phone or leaving a note on your calendar.

Trelstar works to treat advanced prostate cancer by stopping your body from making the hormone testosterone. Prostate cancer needs testosterone in order to grow and spread in your body.

Trelstar contains the drug triptorelin, which belongs to a class of medications called gonadotropin-releasing hormone (GnRH) agonists. By lowering your testosterone level, Trelstar helps to slow prostate cancer tumor growth. For some people, it may even shrink their prostate cancer tumors. By doing this, the drug can reduce your symptoms of the condition and help to improve your quality of life.

How long does it take to work?

Trelstar starts to work soon after it's injected. In clinical studies, people's testosterone levels were measured just 29 days after their first Trelstar injection. At that time, 91.2% to 97.7% of men taking Trelstar had their testosterone level reduced to less than 50 ng/dL.

Low testosterone levels help show that your prostate cancer is not getting worse. A testosterone level of at least 300 ng/dL is typically considered normal for men. However, a level below 50 ng/dL is the goal when treating prostate cancer.

Trelstar is not approved for use in pregnant women or women who are planning to become pregnant. In animal studies, Trelstar increased the risk of miscarriage when it was given to pregnant females. Even though animal studies don't always predict what will happen in humans, it's not recommended that Trelstar be used by pregnant women.

For more information about the safety of using Trelstar during pregnancy, talk with your doctor.

Trelstar's effect on fertility

Because Trelstar may cause infertility in males using the drug, it can reduce a man's ability to get a woman pregnant. If you have concerns about infertility caused by Trelstar treatment, talk with your doctor before starting this drug.

It's recommended that Trelstar not be used during pregnancy. If you're sexually active and you or your partner can become pregnant, talk with your doctor about your birth control needs while you're using Trelstar.

It's not known if Trelstar is safe to use while you're breastfeeding. There haven't been any studies done to show if Trelstar passes into the breast milk of lactating women or animals. However, there may be risk of serious side effects for a child who consumes Trelstar through breast milk.

For more information about breastfeeding while using Trelstar, talk with your doctor.

Before taking Trelstar, talk with your doctor about your health history. Trelstar may not be right for you if you have certain medical conditions or other factors affecting your health. These include:

  • Liver damage. If you have liver damage, your liver may have trouble metabolizing (breaking down) Trelstar. This can increase your risk of side effects from Trelstar. If you have any liver problems, talk with your doctor before starting Trelstar.
  • Kidney damage. If you have kidney damage, your level of Trelstar may be higher than it is in people without kidney damage. This can increase your risk of side effects from Trelstar. If you have any problems with your kidneys, talk with your doctor before starting Trelstar.
  • Diabetes. Trelstar may increase your blood sugar level. This may increase your risk of diabetes or worsen diabetes if you already have the condition. Talk with your doctor about whether you'll need to monitor your blood sugar levels during Trelstar treatment.
  • Heart problems. Trelstar may increase your risk of cardiovascular problems such as heart attack, stroke, or death caused by heart issues. If you already have heart disease, your doctor may want to monitor you more closely while you're taking Trelstar.
  • Severe allergic reaction. You shouldn't take Trelstar if you've had an allergic reaction to Trelstar or other similar drugs (called GnRH agonists) in the past. If you're unsure of whether you've had an allergic reaction to Trelstar or a different GnRH agonist, talk with your doctor.
  • Pregnancy. Trelstar is not approved for use in pregnant women or in women who are planning to become pregnant. For more information, please see the "Trelstar and pregnancy" section above.
  • Breastfeeding. It's not known if Trelstar is safe to use while breastfeeding. For more information, please see the "Trelstar and breastfeeding" section above.

Note: For more information about the potential negative effects of Trelstar, see the "Trelstar side effects" section above.

The following information is provided for clinicians and other healthcare professionals.

Indications

Trelstar is approved by the Food and Drug Administration (FDA) for palliative treatment of advanced prostate cancer in adult men.

Mechanism of action

Trelstar is a gonadotropin-releasing hormone (GnRH) agonist. It works by binding to GnRH receptors to reduce the secretion of gonadotropins, effectively reducing testosterone production to levels seen in surgically castrated men.

Pharmacokinetics and metabolism

After a single intramuscular injection of Trelstar, mean peak concentrations occur in 1 to 3 hours. Half-life elimination occurs via a three-compartment model, with each half-life being 6 minutes, 45 minutes, and 3 hours, respectively, following an intravenous bolus.

The metabolism of Trelstar is largely unknown in humans, although it is hypothesized to involve hepatic microsomal enzymes in the CYP450 system. Trelstar is excreted via the liver and kidneys.

Contraindications

Trelstar is contraindicated in patients who have known hypersensitivity reactions to Trelstar or to any of its components. It is also contraindicated in patients who have had hypersensitivity to other GnRH agonists or GnRH.

Storage

Trelstar comes in the Trelstar MixJect single-dose delivery system. It should be stored at 68°F to 77°F (20°C to 25°C). Do not freeze Trelstar.

Once Trelstar powder is reconstituted via the MixJect system, it should be administered right away. It should not be stored for future use.

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