May 31, 2016
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Side Effects


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
Treatment-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, 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 Trelstar (triptorelin pamoate for injectable suspension) Side Effects Center for a complete guide to possible side effects


No drug-drug interaction studies involving triptorelin have been conducted.

Human pharmacokinetic data with triptorelin suggest that C-terminal fragments produced by tissue degradation are either degraded completely within tissues or are rapidly degraded further in plasma, or cleared by the kidneys. Therefore, hepatic microsomal enzymes are unlikely to be involved in triptorelin metabolism. However, in the absence of relevant data and as a precaution, hyperprolactinemic drugs should not be used concomitantly with triptorelin since hyperprolactinemia reduces the number of pituitary GnRH receptors.

Read the Trelstar Drug Interactions Center for a complete guide to possible interactions

This monograph has been modified to include the generic and brand name in many instances.

Last reviewed on RxList: 11/24/2014

Side Effects

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