Slideshows Images Quizzes

Copyright © 2018 by RxList Inc. RxList does not provide medical advice, diagnosis or treatment. See additional information.


Last reviewed on RxList: 1/4/2019
Trelstar Side Effects Center

Medical Editor: John P. Cunha, DO, FACOEP

Last reviewed on RxList 01/04/2019

Trelstar (triptorelin pamoate) for Injectable Suspension is a gonadotropin releasing hormone (GnRH) for the palliative treatment of advanced prostate cancer. Common side effects of Trelstar include:

Trelstar is administered by a single intramuscular injection in either buttock. Dosing schedule depends on the product strength selected. Trelstar may interact with other drugs. Tell your doctor all medications and supplements you use. Trelstar is not indicated for use in women and is therefore unlikely to be used during pregnancy while breastfeeding; consult your doctor.

Our Trelstar (triptorelin pamoate) for Injectable Suspension Side Effects Drug Center provides a comprehensive view of available drug information on the potential side effects when taking this medication.

This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.


See Images
Trelstar Professional Information


Clinical Trials Experience

Because clinical trials are conducted under widely varying conditions, adverse reaction rates observed in the clinical trials of a drug cannot be directly compared with rates in the clinical trials of another drug and may not reflect the rates observed in practice.

The safety of the three TRELSTAR formulations was evaluated in clinical trials involving patients with advanced prostate cancer. Mean testosterone levels increased above baseline during the first week following the initial injection, declining thereafter to baseline levels or below by the end of the second week of treatment. The transient increase in testosterone levels may be associated with temporary worsening of disease signs and symptoms, including bone pain, neuropathy, hematuria, and urethral or bladder outlet obstruction. Isolated cases of spinal cord compression with weakness or paralysis of the lower extremities have occurred [see WARNINGS AND PRECAUTIONS].

Adverse reactions reported for each of the three TRELSTAR formulations in the clinical trials, are presented in Table 2, Table 3, and Table 4. Often, causality is difficult to assess in patients with metastatic prostate cancer. The majority of adverse reactions related to triptorelin are a result of its pharmacological action, i.e., the induced variation in serum testosterone levels, either an increase in testosterone at the initiation of treatment, or a decrease in testosterone once castration is achieved. Local reactions at the injection site or allergic reactions may occur.

The following adverse reactions were reported to have a possible or probable relationship to therapy as ascribed by the treating physician in at least 1% of patients receiving TRELSTAR 3.75 mg.

Table 2. TRELSTAR 3.75 mg: Treatment-Related Adverse Reactions Reported by 1% or More of Patients During Treatment

Adverse Reactions* TRELSTAR 3.75 mg
N = 140
N %
Application Site Disorders
Injection site pain 5 3.6
Body as a Whole
Hot flush 82 58.6
Pain 3 2.1
Leg pain 3 2.1
Fatigue 3 2.1
Cardiovascular Disorders
Hypertension 5 3.6
Central and Peripheral Nervous System Disorders
Headache 7 5.0
Dizziness 2 1.4
Gastrointestinal Disorders
Diarrhea 2 1.4
Vomiting 3 2.1
Musculoskeletal System Disorders
Skeletal pain 17 12.1
Psychiatric Disorders
Insomnia 3 2.1
Impotence 10 7.1
Emotional lability 2 1.4
Red Blood Cell Disorders
Anemia 2 1.4
Skin and Appendages Disorders
Pruritus 2 1.4
Urinary System Disorders
Urinary tract infection 2 1.4
Urinary retention 2 1.4
* Adverse reactions for TRELSTAR 3.75 mg are coded using the WHO Adverse Reactions Terminology (WHOART)

The following adverse reactions were reported to have a possible or probable relationship to therapy as ascribed by the treating physician in at least 1% of patients receiving TRELSTAR 11.25 mg.

Table 3: TRELSTAR 11.25 mg: Treatment-Related Adverse Reactions Reported by 1% or More of Patients During Treatment

Adverse Reactions* TRELSTAR 11.25 mg
N = 174
N %
Application Site
Injection site pain 7 4.0
Body as a Whole
Hot flush 127 73.0
Leg pain 9 5.2
Pain 6 3.4
Back pain 5 2.9
Fatigue 4 2.3
Chest pain 3 1.7
Asthenia 2 1.1
Peripheral edema 2 1.1
Cardiovascular Disorders
Hypertension 7 4.0
Dependent edema 4 2.3
Central and Peripheral Nervous System Disorders
Headache 12 6.9
Dizziness 5 2.9
Leg cramps 3 1.7
Breast pain 4 2.3
Gynecomastia 3 1.7
Gastrointestinal Disorders
Nausea 5 2.9
Constipation 3 1.7
Dyspepsia 3 1.7
Diarrhea 2 1.1
Abdominal pain 2 1.1
Liver and Biliary System
Abnormal hepatic function 2 1.1
Metabolic and Nutritional Disorders
Edema in legs 11 6.3
Increased alkaline phosphatase 3 1.7
Musculoskeletal System Disorders
Skeletal pain 23 13.2
Arthralgia 4 2.3
Myalgia 2 1.1
Psychiatric Disorders
Decreased libido 4 2.3
Impotence 4 2.3
Insomnia 3 1.7
Anorexia 3 1.7
Respiratory System Disorders
Coughing 3 1.7
Dyspnea 2 1.1
Pharyngitis 2 1.1
Skin and Appendages
Rash 3 1.7
Urinary System Disorders
Dysuria 8 4.6
Urinary retention 2 1.1
Vision Disorders
Eye pain 2 1.1
Conjunctivitis 2 1.1
* Adverse reactions for TRELSTAR 11.25 mg are coded using the WHO Adverse Reactions Terminology (WHOART)

The following adverse reactions occurred in at least 5% of patients receiving TRELSTAR 22.5 mg. The table includes all reactions whether or not they were ascribed to TRELSTAR by the treating physician. The table also includes the incidence of these adverse reactions that were considered by the treating physician to have a reasonable causal relationship or for which the relationship could not be assessed.

Table 4: TRELSTAR 22.5 mg: Adverse Reactions Reported by 5% or More of Patients During Treatment

Adverse Reactions* TRELSTAR 22.5 mg
N = 120
T reatment-Emergent Treatment- Related
N % N %
General Disorders and Administration Site Conditions
Edema peripheral 6 5.0 0 0
Infections and Infestations
Influenza 19 15.8 0 0
Bronchitis 6 5.0 0 0
Diabetes Mellitus/Hyperglycemia 6 5.0 0 0
Musculoskeletal and Connective Tissue Disorders
Back pain 13 10.8 1 0.8
Arthralgia 9 7.5 1 0.8
Pain in extremity 9 7.5 1 0.8
Nervous System Disorders
Headache 9 7.5 2 1.7
Psychiatric Disorders
Insomnia 6 5.0 1 0.8
Renal and Urinary Disorders
Urinary tract infection 14 11.6 0 0
Urinary retention 6 5.0 0 0
Reproductive System and Breast Disorders
Erectile dysfunction 12 10.0 12 10.0
Testicular atrophy 9 7.5 9 7.5
Vascular Disorders
Hot flush 87 72.5 86 71.7
Hypertension 17 14.2 1 0.8
* Adverse reactions for TRELSTAR 22.5 mg are coded using the Medical Dictionary for Regulatory Activities (MedDRA)

Changes In Laboratory Values During Treatment

The following abnormalities in laboratory values not present at baseline were observed in 10% or more of patients:

TRELSTAR 3.75 mg: There were no clinically meaningful changes in laboratory values detected during therapy.

TRELSTAR 11.25 mg: Decreased hemoglobin and RBC count and increased glucose, BUN, SGOT, SGPT, and alkaline phosphatase at the Day 253 visit.

TRELSTAR 22.5 mg: Decreased hemoglobin and increased glucose and hepatic transaminases were detected during the study. The majority of the changes were mild to moderate.

Postmarketing Experience

The following adverse reactions have been identified during post approval use of gonadotropin releasing hormone agonists. Because these reactions are reported voluntarily from a population of uncertain size, it is not always possible to reliably estimate their frequency or establish a causal relationship to drug exposure.

During postmarketing surveillance, rare cases of pituitary apoplexy (a clinical syndrome secondary to infarction of the pituitary gland) have been reported after the administration of gonadotropin-releasing hormone agonists. In a majority of these cases, a pituitary adenoma was diagnosed with a majority of pituitary apoplexy cases occurring within 2 weeks of the first dose, and some within the first hour. In these cases, pituitary apoplexy has presented as sudden headache, vomiting, visual changes, ophthalmoplegia, altered mental status, and sometimes cardiovascular collapse. Immediate medical attention has been required.

During postmarketing experience, convulsions, interstitial lung disease, and thromboembolic events including, but not limited to, pulmonary emboli, cerebrovascular accident, myocardial infarction, deep venous thrombosis, transient ischemic attack, and thrombophlebitis have been reported.

Read the entire FDA prescribing information for Trelstar (Triptorelin Pamoate for Injectable Suspension)


Screening Tests Every Man Should Have See Slideshow
Related Resources for Trelstar

© Trelstar Patient Information is supplied by Cerner Multum, Inc. and Trelstar Consumer information is supplied by First Databank, Inc., used under license and subject to their respective copyrights.

Health Solutions From Our Sponsors