Class: Hormonal Therapy

Generic Name: triptorelin pamoate (TRIP-toe-REL-in PAM-oh-ate) for injectable suspension

Trade Name: Trelstar

For which conditions is this drug approved? Trelstar is indicated for the palliative treatment of advanced prostate cancer.

What is the mechanism of action? Trelstar is a gonadotropin releasing hormone (GnRH) agonist, which inhibits secretion of gonadotropin and thus causes the testicles to stop making testosterone.

How is Trelstar typically given (administered)? Trelstar is administered as a single intramuscular injection in either buttock. Dosage strengths are selected based upon the desired dosing schedule.

How are patients typically monitored?

• Patients will typically have follow-up meetings to assess tolerance and response to therapy. Follow-up may include blood tests to measure serum levels of testosterone, physical examinations, scans, and other measures.
• Patients with metastatic vertebral lesions and/or with upper or lower urinary tract obstruction during the first few weeks of therapy should be closely observed.
• Rarely, anaphylactic shock, hypersensitivity, and angioedema (swelling under the surface of the skin) have been reported. In the event of a reaction, discontinue Trelstar and initiate appropriate medical management.
• Tumor flare, or temporary increase in serum testosterone levels, can occur within the first few weeks of treatment. This may worsen prostate cancer and result in spinal cord compression and urinary tract obstruction. Patients at risk should be monitored and managed as appropriate.
• Because hyperglycemia (high blood sugar) and an increased risk of developing diabetes have been reported in men receiving GnRH agonists, blood glucose levels should be monitored and managed.
• Patients should also be monitored for cardiovascular complications.

What are the common (occur in 30% or more of patients) side effects of treatment with Trelstar?

• Hot flushes

What are the less common (occur in 10% to 29% of patients) side effects of treatment with Trelstar?

• Skeletal pain
• Erectile dysfunction
• Influenza
• Back pain
• Urinary tract infection
• Hypertension

This is not a complete list of side effects. Some patients may experience other side effects that are not listed here. Patients may wish to discuss with their physician the other less common side effects of this drug, some of which may be serious.

Some side effects may require medical attention. Other side effects do not require medical attention and may go away during treatment. Patients should check with their physician about any side effects that continue or are bothersome.

What can patients do to help alleviate or prevent discomfort and side effects?

• Pay careful attention to the physician’s instructions and inform the physician of any side effects.
• Patients who experience hot flushes may wish to wear light clothing, stay in a cool environment, and place cool cloths on their body or head to relieve their symptoms
• Maintain adequate rest and nutrition.
• Wear sunscreen and protective clothing and try to minimize sun exposure.
• Drink plenty of fluids. (Patients should ask their physician about the amount of liquid to consume during a day.)

Are there any special precautions patients should be aware of before starting treatment?

• Patients will likely experience an increase in serum testosterone levels following their initial injection. This may cause a worsening of symptoms of prostate cancer during the first weeks of treatment. These symptoms may include bone pain, spinal cord injury, hematuria, and urethral or bladder outlet obstruction. Increase in serum testosterone levels and associated symptoms should decline three to four weeks following injection. Patients and physicians should discuss use of drugs appropriate for alleviating the risk associated with this increase prior to administration of Trelstar.
• Patients should also be informed about the increased risk of developing diabetes, myocardial infarction, sudden cardiac death, and stroke association with use of GnRH agonists.
• Allergic reactions (sometimes serious) can occur and, if severe, require immediate treatment.
• Patients should report any previous hypersensitivity reactions to Trelstar, other GnRH agonists, or GnRH.
• Trelstar is contraindicated in women who are or may become pregnant.

When should patients notify their physician?

• If they have signs of a serious allergic reaction to Trelstar
• If they have signs of hypersensitivity
• If they have signs of cardiac complications or allergic reaction
• If they experience any side effects that don’t go away

What is a package insert?

A package insert is required by the FDA and contains a summary of the essential scientific information needed for the safe and effective use of the drug for healthcare providers and consumers.  A package insert typically includes information regarding specific indications, administration schedules, dosing, side effects, contraindications, results from some clinical trials, chemical structure, pharmacokinetics and metabolism of the specific drug. By carefully reviewing the package insert, you will get the most complete and current information about how to safely use this drug. If you do not have the package insert for the drug you are using, your pharmacist or physician may be able to provide you with a copy.

Tags: Drug Dictionary, Hormonal Therapy, T