Zoladex Side Effects Center

Last updated on RxList: 6/30/2021
Zoladex Side Effects Center

What Is Zoladex?

Zoladex 10.8 (goserelin acetate implant) is a man-made form of a hormone used in men to treat symptoms of prostate cancer, and in women to treat breast cancer or endometriosis. Zoladex 10.8 is also used in women to prepare the lining of the uterus for endometrial ablation (a surgery to correct abnormal uterine bleeding). Zoladex 10.8 treats only the symptoms of prostate cancer but does not treat the cancer itself.

What Are Side Effects of Zoladex?

Common side effects of Zoladex 10.8 include:

  • hot flashes (flushing)
  • dizziness
  • headache
  • increased sweating
  • increased or decreased sexual interest
  • impotence
  • fewer erections than usual
  • trouble sleeping
  • nausea
  • change in breast size
  • breast swelling or tenderness
  • vaginal dryness/itching/discharge
  • hair loss, mental/mood changes (such as depression, mood swings, hallucinations)
  • injection site reactions (pain, bruising, bleeding, redness, or swelling)
  • bone pain
  • diarrhea
  • constipation
  • sleep problems (insomnia)
  • acne, or
  • skin rash or itching

Dosage for Zoladex

Zoladex, at a dose of 10.8 mg, is administered subcutaneously every 12 weeks under the supervision of a physician. For female patients the 3.6 mg implant is used.

What Drugs, Substances, or Supplements Interact with Zoladex?

There may be other drugs that can interact with Zoladex. Tell your doctor about all your prescription and over-the-counter medications, vitamins, minerals, herbal products, and drugs prescribed by other doctors.

Zoladex During Pregnancy or Breastfeeding

Zoladex is not recommended for use during pregnancy. It may harm a fetus. Women of child-bearing age must not be pregnant when starting this medication. Consult your doctor to discuss use of birth control. For women, this medication should stop the release of an egg (ovulation) and your periods, but this should not be used as a reliable method of birth control. It is recommended that men and women using this medication use 2 forms of non-hormonal birth control (e.g., condoms and diaphragm with spermicide) while taking this medication. Continue using birth control until the return of the woman's period or for at least 12 weeks after stopping this medication. It is not known whether this medication passes into breast milk. Because of the possible risk to the infant, breastfeeding while using this medication is not recommended.

Additional Information

Our Zoladex (goserelin acetate implant) 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.


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Zoladex Consumer Information

Get emergency medical help if you have signs of an allergic reaction: hives; difficult breathing; swelling of your face, lips, tongue, or throat.

When you start treatment with goserelin, your tumor symptoms may get worse for a short time. Worsening of a prostate tumor may increase pressure on your spinal cord or urinary tract. Tell your doctor right away if you have symptoms such as: back pain, painful or difficult urination, loss of movement in any part of your body, or loss of bowel or bladder control.

Call your doctor at once if you have:

  • pain, bruising, swelling, redness, oozing, or bleeding where the implant was injected;
  • dizziness, trouble breathing, feeling light-headed (like you might pass out);
  • high blood sugar--increased thirst, increased urination, dry mouth, fruity breath odor;
  • high calcium levels--confusion, tiredness, nausea, vomiting, loss of appetite, constipation, increased thirst or urination, weight loss;
  • heart attack symptoms--chest pain or pressure, pain spreading to your jaw or shoulder, nausea, sweating; or
  • signs of a blood clot--sudden numbness or weakness on one side of the body, chest pain, problems with vision or speech, pain or swelling in one leg.

Common side effects may include:

  • hot flashes, sweating;
  • painful urination;
  • mood changes, increased or decreased interest in sex;
  • changes in sexual function, fewer erections than normal;
  • headache;
  • swelling in your hands or feet;
  • vaginal dryness, itching, or discharge;
  • changes in breast size; or
  • acne, mild skin rash or itching.

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.

Read the entire detailed patient monograph for Zoladex (Goserelin Acetate Implant)


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Zoladex Professional Information


Stage B2-C Prostatic Carcinoma

Treatment with ZOLADEX and flutamide did not add substantially to the toxicity of radiation treatment alone. The following adverse experiences were reported during a multicenter clinical trial comparing ZOLADEX + flutamide + radiation versus radiation alone. The most frequently reported (greater than 5%) adverse experiences are listed below:

Table 1 ADVERSE EVENTS DURING ACUTE RADIATION THERAPY (within first 90 days of radiation therapy)

flutamide + ZOLADEX + Radiation
Radiation Only
% All % All
Rectum/Large Bowel 80 76
Bladder 58 60
Skin 37 37

Table 2 ADVERSE EVENTS DURING LATE RADIATION PHASE (after 90 days of radiation therapy)

flutamide + ZOLADEX + Radiation
Radiation Only
% All % All
Diarrhea 36 40
Cystitis 16 16
Rectal Bleeding 14 20
Proctitis 8 8
Hematuria 7 12

Additional adverse event data was collected for the combination therapy with radiation group over both the hormonal treatment and hormonal treatment plus radiation phases of the study. Adverse experiences occurring in more than 5% of patients in this group, over both parts of the study, were hot flashes (46%), diarrhea (40%), nausea (9%), and skin rash (8%).

Prostatic Carcinoma

ZOLADEX has been found to be generally well tolerated in clinical trials. Adverse reactions reported in these trials were rarely severe enough to result in the patients’ withdrawal from ZOLADEX treatment. As seen with other hormonal therapies, the most commonly observed adverse events during ZOLADEX therapy were due to the expected physiological effects from decreased testosterone levels. These included hot flashes, sexual dysfunction and decreased erections.

Tumor Flare Phenomenon

Initially, ZOLADEX, like other GnRH agonists, causes transient increases in serum levels of testosterone. A small percentage of patients experienced a temporary worsening of signs and symptoms, usually manifested by an increase in cancer-related pain which was managed symptomatically. Isolated cases of exacerbation of disease symptoms, either ureteral obstruction or spinal cord compression, occurred at similar rates in controlled clinical trials with both ZOLADEX and orchiectomy. The relationship of these events to therapy is uncertain [see WARNINGS AND PRECAUTIONS].

In the controlled clinical trials of ZOLADEX versus orchiectomy, the following events were reported as adverse reactions in greater than 5% of the patients.


Hot Flashes 62 53
Sexual Dysfunction 21 15
Decreased Erections 18 16
Lower Urinary Tract Symptoms 13 8
Lethargy 8 4
Pain (worsened in the first 30 days) 8 3
Edema 7 8
Upper Respiratory Infection 7 2
Rash 6 1
Sweating 6 4
Anorexia 5 2
Chronic Obstructive Pulmonary Disease 5 3
Congestive Heart Failure 5 1
Dizziness 5 4
Insomnia 5 1
Nausea 5 2
Complications of Surgery 0 181
1. Complications related to surgery were reported in 18% of the orchiectomy patients, while only 3% of ZOLADEX patients reported adverse reactions at the injection site. The surgical complications included scrotal infection (5.9%), groin pain (4.7%), wound seepage (3.1%), scrotal hematoma (2.8%), incisional discomfort (1.6%) and skin necrosis (1.2%).

The following additional adverse reactions were reported in greater than 1% but less than 5% of the patients treated with ZOLADEX:

CARDIOVASCULAR – arrhythmia, cerebrovascular accident, hypertension, myocardial infarction, peripheral vascular disorder, chest pain;
CENTRAL NERVOUS SYSTEM – anxiety, depression, headache;
GASTROINTESTINAL – constipation, diarrhea, ulcer, vomiting;
METABOLIC/NUTRITIONAL – gout, hyperglycemia, weight increase;
MISCELLANEOUS – chills, fever;
UROGENITAL – renal insufficiency, urinary obstruction, urinary tract infection, breast swelling and tenderness.


As would be expected with a drug that results in hypoestrogenism, the most frequently reported adverse reactions were those related to this effect.


In controlled clinical trials comparing ZOLADEX every 28 days and danazol daily for the treatment of endometriosis, the following events were reported at a frequency of 5% or greater.


Hot Flushes 96 67
Vaginitis 75 43
Headache 75 63
Emotional Lability 60 56
Libido Decreased 61 44
Sweating 45 30
Depression 54 48
Acne 42 55
Breast Atrophy 33 42
Seborrhea 26 52
Peripheral Edema 21 34
Breast Enlargement 18 15
Pelvic Symptoms 18 23
Pain 17 16
Dyspareunia 14 5
Libido Increased 12 19
Infection 13 11
Asthenia 11 13
Nausea 8 14
Hirsutism 7 15
Insomnia 11 4
Breast Pain 7 4
Abdominal Pain 7 7
Back Pain 7 13
Flu Syndrome 5 5
Dizziness 6 4
Application Site Reaction 6 -
Voice Alterations 3 8
Pharyngitis 5 2
Hair Disorders 4 11
Myalgia 3 11
Nervousness 3 5
Weight Gain 3 23
Leg Cramps 2 6
Increased Appetite 2 5
Pruritus 2 6
Hypertonia 1 10

The following adverse events not already listed above were reported at a frequency of 1% or greater, regardless of causality, in ZOLADEX-treated women from all clinical trials:

WHOLE BODY – allergic reaction, chest pain, fever, malaise;
CARDIOVASCULAR – hemorrhage, hypertension, migraine, palpitations, tachycardia;
DIGESTIVE – anorexia, constipation, diarrhea, dry mouth, dyspepsia, flatulence;
HEMATOLOGIC – ecchymosis;
MUSCULOSKELETAL – arthralgia, joint disorder;
CNS – anxiety, paresthesia, somnolence, thinking abnormal;
RESPIRATORY – bronchitis, cough increased, epistaxis, rhinitis, sinusitis;
SKIN – alopecia, dry skin, rash, skin discoloration;
SPECIAL SENSES – amblyopia, dry eyes;
UROGENITAL – dysmenorrhea, urinary frequency, urinary tract infection, vaginal hemorrhage.

Endometrial Thinning

The following adverse events were reported at a frequency of 5% or greater in premenopausal women presenting with dysfunctional uterine bleeding in Trial 0022 for endometrial thinning. These results indicate that headache, hot flushes and sweating were more common in the ZOLADEX group than in the placebo group.


ZOLADEX 3.6 mg
Whole Body
Headache 32 22
Abdominal Pain 11 10
Pelvic Pain 9 6
Back Pain 4 7
Vasodilatation 57 18
Migraine 7 4
Hypertension 6 2
Nausea 5 6
Nervousness 5 3
Depression 3 7
Pharyngitis 6 9
Sinusitis 3 6
Skin and appendages
Sweating 16 5
Dysmenorrhea 7 9
Uterine Hemorrhage 6 4
Vulvovaginitis 5 1
Menorrhagia 4 5
Vaginitis 1 6

Breast Cancer

The adverse event profile for women with advanced breast cancer treated with ZOLADEX is consistent with the profile described above for women treated with ZOLADEX for endometriosis. In a controlled clinical trial (SWOG–8692) comparing ZOLADEX with oophorectomy in premenopausal and perimenopausal women with advanced breast cancer, the following events were reported at a frequency of 5% or greater in either treatment group regardless of causality.


ADVERSE EVENT % of Pts. % of Pts.
Hot Flashes 70 47
Tumor Flare 23 4
Nausea 11 7
Edema 5 0
Malaise/Fatigue/Lethargy 5 2
Vomiting 4 7

In the Phase II clinical trial program in 333 pre- and perimenopausal women with advanced breast cancer, hot flashes were reported in 75.9% of patients and decreased libido was noted in 47.7% of patients. These two adverse events reflect the pharmacological actions of ZOLADEX.

Injection site reactions were reported in less than 1% of patients.

Hormone Replacement Therapy

Clinical studies suggest the addition of Hormone Replacement Therapy (estrogens and/or progestins) to ZOLADEX may decrease the occurrence of vasomotor symptoms and vaginal dryness associated with hypoestrogenism without compromising the efficacy of ZOLADEX in relieving pelvic symptoms. The optimal drugs, dose and duration of treatment has not been established.

Changes In Bone Mineral Density

After 6 months of ZOLADEX treatment, 109 female patients treated with ZOLADEX showed an average 4.3% decrease of vertebral trabecular bone mineral density (BMD) as compared to pretreatment values. BMD was measured by dual-photon absorptiometry or dual energy x-ray absorptiometry. Sixty-six of these patients were assessed for BMD loss 6 months after the completion (posttherapy) of the 6-month therapy period. Data from these patients showed an average 2.4% BMD loss compared to pretreatment values.

Twenty-eight of the 109 patients were assessed for BMD at 12 months posttherapy. Data from these patients showed an average decrease of 2.5% in BMD compared to pretreatment values. These data suggest a possibility of partial reversibility. Clinical studies suggest the addition of Hormone Replacement Therapy (estrogens and/or progestins) to ZOLADEX is effective in reducing the bone mineral loss which occurs with ZOLADEX alone without compromising the efficacy of ZOLADEX in relieving the symptoms of endometriosis. The optimal drugs, dose and duration of treatment has not been established [see PATIENT INFORMATION].

Changes In Laboratory Values During Treatment

Plasma Enzymes

Elevation of liver enzymes (AST, ALT) have been reported in female patients exposed to ZOLADEX (representing less than 1% of all patients).


In a controlled trial, ZOLADEX therapy resulted in a minor, but statistically significant effect on serum lipids. In patients treated for endometriosis at 6 months following initiation of therapy, danazol treatment resulted in a mean increase in LDL cholesterol of 33.3 mg/dL and a decrease in HDL cholesterol of 21.3 mg/dL compared to increases of 21.3 and 2.7 mg/dL in LDL cholesterol and HDL cholesterol, respectively, for ZOLADEX-treated patients. Triglycerides increased by 8.0 mg/dL in ZOLADEX-treated patients compared to a decrease of 8.9 mg/dL in danazol-treated patients.

In patients treated for endometriosis, ZOLADEX increased total cholesterol and LDL cholesterol during 6 months of treatment. However, ZOLADEX therapy resulted in HDL cholesterol levels which were significantly higher relative to danazol therapy. At the end of 6 months of treatment, HDL cholesterol fractions (HDL2 and HDL3) were decreased by 13.5 and 7.7 mg/dL, respectively, for danazol-treated patients compared to treatment increases of 1.9 and 0.8 mg/dL, respectively, for ZOLADEX-treated patients.

Postmarketing Experience

The following adverse reactions have been identified during post-approval use of ZOLADEX. 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.

Bone Mineral Density

Osteoporosis, decreased bone mineral density and bone fracture in men [see PATIENT INFORMATION].


Deep vein thrombosis, pulmonary embolism, myocardial infarction, stroke, and transient ischemic attack have been observed in women treated with GnRH agonists. Although a temporal relationship was reported in some cases, most cases were confounded by risk factors or concomitant medication use. It is unknown if there is a causal association between the use of GnRH analogs and these events.

Ovarian Cyst

Ovarian cyst formation and, in combination with gonadotropins, ovarian hyperstimulation syndrome (OHSS).

Changes In Blood Pressure

Hypotension and hypertension have been reported. These changes are usually transient, resolving either during continued therapy or after cessation of therapy.

Pituitary Apoplexy And Tumors

Pituitary apoplexy (a clinical syndrome secondary to infarction of the pituitary gland) and pituitary adenoma have been diagnosed. Most of the pituitary apoplexy cases occurred within 2 weeks of the first dose, and some occurred 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. Pituitary tumors have been reported.


Usually within one month of starting treatment.

Other Adverse Reactions

Psychotic disorders, convulsions and mood swings.


No formal drug-drug interaction studies have been performed. No confirmed interactions have been reported between ZOLADEX and other drugs.

Drug/Laboratory Test Interactions

Administration of ZOLADEX in therapeutic doses results in suppression of the pituitary-gonadal system. Because of this suppression, diagnostic tests of pituitarygonadotropic and gonadal functions conducted during treatment and until the resumption of menses may show results which are misleading. Normal function is usually restored within 12 weeks after treatment is discontinued.

Read the entire FDA prescribing information for Zoladex (Goserelin Acetate Implant)

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

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