Zoladex: Uses, Dosage & Side Effects
A GnRH agonist implant used to suppress sex hormones for the treatment of prostate cancer, breast cancer, endometriosis, and uterine fibroids
Zoladex (goserelin) is a gonadotropin-releasing hormone (GnRH) agonist administered as a subcutaneous implant. It works by initially stimulating, then suppressing the pituitary gland's release of gonadotropins, which leads to a marked reduction in testosterone levels in men and estrogen levels in women. In men, Zoladex is primarily used for the treatment of prostate cancer, achieving medical castration without the need for surgical orchidectomy. In women, it is prescribed for endometriosis, hormone receptor-positive breast cancer, uterine fibroids (as pre-operative treatment), and prior to endometrial resection. Zoladex is injected every 28 days (3.6 mg) or every 12 weeks (10.8 mg) by a healthcare professional and has been a cornerstone of hormone-deprivation therapy since its approval.
Quick Facts: Zoladex
Key Takeaways
- Zoladex (goserelin) is a GnRH agonist that suppresses sex hormone production – lowering testosterone in men and estrogen in women – by downregulating the pituitary gland after an initial transient hormone surge.
- In men it is primarily used for prostate cancer treatment, while in women it treats endometriosis, breast cancer, and uterine fibroids; each indication has specific treatment duration guidelines.
- An initial “tumor flare” effect during the first 1–2 weeks of treatment in prostate cancer patients may temporarily worsen symptoms; antiandrogen cover is often prescribed to manage this.
- The implant is injected subcutaneously into the abdominal wall every 28 days (3.6 mg) or every 12 weeks (10.8 mg) by a healthcare professional and must not be self-administered.
- Long-term use can reduce bone mineral density; patients should be monitored for osteoporosis, and depression has been reported – seek medical advice if mood changes occur during treatment.
What Is Zoladex and What Is It Used For?
Zoladex contains the active substance goserelin, a synthetic analogue of naturally occurring gonadotropin-releasing hormone (GnRH), also known as luteinizing hormone-releasing hormone (LHRH). The hypothalamus in the brain normally releases GnRH in a pulsatile fashion, stimulating the pituitary gland to secrete luteinizing hormone (LH) and follicle-stimulating hormone (FSH). These gonadotropins, in turn, stimulate the gonads (testes in men and ovaries in women) to produce sex hormones – testosterone and estrogen respectively. By providing a continuous, non-pulsatile supply of GnRH analogue, Zoladex disrupts this normal hormonal axis.
When Zoladex treatment begins, the continuous stimulation of GnRH receptors on the pituitary gland initially causes a transient increase in LH and FSH secretion, which leads to a temporary rise in testosterone or estrogen levels during the first one to two weeks of therapy. This phenomenon is known as the “flare effect.” However, with sustained exposure to goserelin, the pituitary GnRH receptors become desensitized and downregulated, resulting in a profound suppression of gonadotropin release. Consequently, testosterone levels in men fall to castrate levels (typically below 50 ng/dL), and estrogen levels in women decrease to postmenopausal concentrations. This hormonal suppression is maintained for as long as treatment continues and is reversible upon discontinuation.
The goserelin implant is a small, biodegradable cylinder composed of a lactide-glycolide copolymer matrix that slowly erodes in the body, releasing goserelin at a controlled rate over the dosing interval. The 3.6 mg implant provides approximately 28 days of continuous drug release, while the 10.8 mg depot formulation delivers medication over approximately 12 weeks. This sustained-release technology eliminates the need for daily injections and ensures consistent hormone suppression throughout the treatment period.
Indications in Men
In men, Zoladex is approved and widely used for the treatment of prostate cancer, which is the most common non-skin cancer in men worldwide. Prostate cancer cells frequently depend on testosterone for their growth and proliferation. By reducing testosterone to castrate levels, Zoladex effectively starves the tumor of the hormonal stimulus it requires, leading to tumor shrinkage and disease control. This approach, known as androgen deprivation therapy (ADT), is a cornerstone of prostate cancer management and can be used in several clinical settings:
- Locally advanced prostate cancer: Zoladex is used in combination with radiotherapy to improve treatment outcomes. Clinical trials have demonstrated significantly improved overall survival and disease-free survival when ADT is combined with radiation therapy compared with either modality alone.
- Metastatic prostate cancer: For patients with cancer that has spread beyond the prostate, Zoladex provides systemic hormonal suppression that controls disease progression and alleviates symptoms such as bone pain.
- Neoadjuvant and adjuvant therapy: Zoladex may be given before, during, and after radiotherapy. The duration of ADT varies from short-term (4–6 months) for intermediate-risk disease to long-term (2–3 years) for high-risk disease, based on major clinical trial evidence including the EORTC 22863, RTOG 85-31, and RTOG 92-02 studies.
- Biochemical recurrence: Following primary treatment (surgery or radiation), Zoladex may be initiated if prostate-specific antigen (PSA) levels rise, indicating disease recurrence.
Indications in Women
In women, Zoladex is prescribed for several hormone-dependent conditions where reducing estrogen levels provides therapeutic benefit:
- Endometriosis: Zoladex creates a temporary “medical menopause” that causes endometriotic implants to shrink and become inactive, reducing pain, dysmenorrhea, and dyspareunia. Treatment is typically limited to a maximum of six months due to concerns about bone mineral density loss. Add-back therapy with low-dose hormone replacement may be considered to mitigate menopausal side effects and bone loss.
- Breast cancer: In pre- and perimenopausal women with hormone receptor-positive (ER-positive) breast cancer, Zoladex achieves ovarian suppression, reducing estrogen levels and thereby inhibiting the growth of estrogen-dependent tumor cells. It is used as part of adjuvant endocrine therapy, often in combination with tamoxifen or an aromatase inhibitor. The SOFT and TEXT trials demonstrated significant improvements in disease-free survival with ovarian suppression added to standard endocrine therapy in appropriately selected patients.
- Uterine fibroids: Zoladex reduces the size of uterine fibroids (leiomyomas) and controls associated heavy menstrual bleeding and pain. It is typically used as a pre-operative treatment for up to three months to facilitate surgery by reducing fibroid volume, correcting associated anemia, and potentially allowing a less invasive surgical approach.
- Endometrial thinning: Prior to endometrial resection or ablation procedures, two Zoladex implants administered 28 days apart can reduce endometrial thickness, improving procedural outcomes.
The hormonal effects of Zoladex are fully reversible upon discontinuation of treatment. In women, menstrual periods typically resume within 8–12 weeks after the last injection, and fertility generally returns thereafter. In men, testosterone levels usually recover within several months of stopping treatment, although the speed of recovery may vary depending on the duration of therapy and individual patient factors.
What Should You Know Before Taking Zoladex?
Contraindications
Zoladex must not be used in patients with a known hypersensitivity (allergy) to goserelin or to any of the excipients in the formulation, including the lactide-glycolide copolymer. While severe allergic reactions are rare, anaphylactic reactions have been reported. If you have previously experienced an allergic reaction to any GnRH agonist, inform your doctor before starting treatment.
Zoladex is contraindicated during pregnancy and breastfeeding. There is a theoretical risk of miscarriage or fetal abnormality if GnRH agonists are used during pregnancy. Women of childbearing potential must use non-hormonal contraception (such as condoms or an intrauterine device) throughout treatment. Oral contraceptive pills should not be used during Zoladex therapy as they may interfere with the mechanism of action. If pregnancy occurs despite these precautions, the patient must inform her doctor immediately.
Warnings and Precautions
During the first weeks of treatment, Zoladex causes a temporary increase in testosterone levels that may worsen prostate cancer symptoms. This can lead to increased bone pain, urinary obstruction, or in rare cases spinal cord compression which can cause paralysis. If you have had difficulty urinating or problems in the lower back, tell your doctor before starting treatment. Your doctor may prescribe an antiandrogen medication to counteract this initial flare.
Before and during treatment with Zoladex, inform your doctor if any of the following conditions apply:
- Bone health: Zoladex can reduce bone mineral density (osteopenia/osteoporosis) because it lowers sex hormone levels. If you have any condition that affects bone strength, such as existing osteoporosis, a family history of osteoporosis, chronic alcohol use, smoking, or long-term use of corticosteroids or anticonvulsants, discuss these with your doctor. Bone density monitoring may be recommended, and calcium and vitamin D supplementation or bisphosphonate therapy may be considered.
- Cardiovascular disease: GnRH agonists have been associated with an increased risk of cardiovascular events including heart attack and heart failure. Tell your doctor if you have a history of heart disease, stroke, high blood pressure, diabetes, or high cholesterol. The risk may be higher when Zoladex is combined with antiandrogen therapy in men with prostate cancer.
- Cardiac arrhythmias (QT prolongation): Zoladex may increase the risk of heart rhythm disturbances (QT prolongation). Inform your doctor if you have a history of arrhythmias, are taking medications known to affect heart rhythm (see drug interactions section), or have electrolyte imbalances.
- Depression: Depression, which can be severe, has been reported in patients taking Zoladex. This may be related to the hormonal changes caused by the medication. If you experience low mood, feelings of hopelessness, loss of interest in activities, or thoughts of self-harm during treatment, inform your doctor promptly.
- Diabetes: Men receiving GnRH agonist therapy may experience impaired glucose tolerance or worsening of pre-existing diabetes. Blood sugar levels should be monitored regularly, and diabetes medication doses may need adjustment.
- Kidney impairment: If you have severely impaired kidney function, tell your doctor, as this may affect how the drug is cleared from your body.
- Hospital admission: If you are admitted to hospital for any reason, inform the healthcare team that you are receiving Zoladex treatment.
Children and Adolescents
Zoladex is not intended for use in children and adolescents under 18 years of age. The safety and efficacy of goserelin in the pediatric population have not been established for the approved indications. Use of GnRH agonists in children is limited to specific pediatric conditions (such as central precocious puberty), for which other formulations with appropriate dosing are available.
Pregnancy and Breastfeeding
Zoladex must not be used during pregnancy or breastfeeding. Women of childbearing potential should have a pregnancy test before starting treatment to confirm they are not pregnant. Non-hormonal contraception (barrier methods such as condoms, or an intrauterine device) must be used throughout treatment. Hormonal contraceptives (oral contraceptive pills, patches, rings) should not be used during Zoladex therapy because the drug interferes with the hormonal mechanisms these contraceptives rely upon.
If a woman becomes pregnant during Zoladex treatment, she should inform her doctor immediately. There is a theoretical risk of miscarriage and fetal abnormality. It is not known whether goserelin is excreted in breast milk, but breastfeeding should be discontinued before starting treatment due to the potential risk to the infant.
Driving and Operating Machinery
Zoladex is not known to directly impair the ability to drive or operate machinery. However, patients are individually responsible for assessing whether they are fit to perform tasks requiring alertness, as some side effects of the medication – such as fatigue, dizziness, mood changes, or visual disturbances – could affect concentration and reaction time. If you experience any such symptoms, exercise caution and consult your doctor before driving or operating machinery.
How Does Zoladex Interact with Other Drugs?
Drug interactions with Zoladex primarily relate to its effects on the cardiovascular system, specifically its potential to prolong the QT interval on an electrocardiogram (ECG). QT prolongation can increase the risk of potentially serious cardiac arrhythmias, including a dangerous type called torsades de pointes. When Zoladex is used concurrently with other drugs known to prolong the QT interval, the risk may be additive. Additionally, the hormonal effects of Zoladex may interact with certain other therapies, particularly those used in cancer treatment.
It is essential to tell your doctor about all medications you are currently taking or have recently taken, including prescription drugs, over-the-counter medicines, and herbal supplements. Your doctor may need to monitor your heart rhythm more closely or adjust your medications to minimize interaction risks.
Major Interactions
| Interacting Drug | Effect | Clinical Significance |
|---|---|---|
| Amiodarone | Additive QT prolongation; increased risk of cardiac arrhythmias | Monitor ECG closely; avoid combination if possible |
| Sotalol | Additive QT prolongation; increased risk of torsades de pointes | ECG monitoring required; consider alternative beta-blocker |
| Quinidine / Procainamide | Additive QT prolongation; increased arrhythmia risk | Avoid concurrent use if possible; regular ECG monitoring |
| Methadone | Additive QT prolongation; arrhythmia risk | ECG monitoring advised; dose adjustment may be needed |
| Antiandrogens (e.g., bicalutamide, flutamide) | Increased risk of heart failure and myocardial infarction when combined with GnRH agonists | Cardiovascular risk assessment before combined ADT; monitor cardiac function |
Minor Interactions
| Interacting Drug | Effect | Clinical Significance |
|---|---|---|
| Moxifloxacin (fluoroquinolone antibiotic) | Additive QT prolongation | Use alternative antibiotic when possible; monitor if co-prescribed |
| Antipsychotics (e.g., haloperidol, quetiapine) | Additive QT prolongation; hormonal interactions | ECG monitoring; use lowest effective antipsychotic dose |
| Hormonal contraceptives (oral, patch, ring) | Reduced contraceptive efficacy due to hormonal interference | Use non-hormonal contraception (condom, IUD) during treatment |
| Diabetes medications (insulin, metformin, sulfonylureas) | GnRH agonists may impair glucose tolerance | Monitor blood glucose more frequently; dose adjustments may be needed |
Because Zoladex can affect heart rhythm (QT interval on ECG), patients should provide their doctor with a complete list of all current medications before starting treatment. This includes medications for heart conditions, antibiotics, antidepressants, antipsychotics, and pain medications. Some over-the-counter medications and herbal supplements may also affect the QT interval.
What Is the Correct Dosage of Zoladex?
Zoladex is always administered by a healthcare professional – either a doctor or a nurse – and must not be self-injected. The implant is injected subcutaneously (under the skin) into the anterior abdominal wall, below the navel. The patient should be lying down or semi-reclined during the procedure. The injection site is cleaned with antiseptic, and the pre-loaded syringe needle is inserted at a 30–45 degree angle into the subcutaneous tissue. It is important not to inject into muscle or through the peritoneum (the membrane lining the abdominal cavity).
Two formulations are available, each designed for specific dosing intervals. The 3.6 mg implant is administered every 28 days (approximately monthly), providing sustained goserelin release for one month. The 10.8 mg depot implant is administered every 12 weeks (approximately every three months) and is primarily used for prostate cancer treatment when a longer dosing interval is preferred for patient convenience. The choice between formulations is made by the prescribing physician based on the clinical indication and individual patient factors.
Adults – Prostate Cancer (Men)
Prostate Cancer
Dose: 3.6 mg subcutaneous implant every 28 days, or 10.8 mg depot implant every 12 weeks
Duration: Treatment is typically long-term and continued for as long as clinically indicated. This may be several years or indefinitely, depending on disease stage, PSA response, and treatment goals. In the adjuvant/neoadjuvant setting with radiotherapy, duration ranges from 4–6 months (intermediate risk) to 2–3 years (high risk).
Important: The doctor may prescribe an antiandrogen (such as bicalutamide or flutamide) for the first few weeks to counteract the initial testosterone flare.
Adults – Endometriosis (Women)
Endometriosis
Dose: 3.6 mg subcutaneous implant every 28 days
Duration: Maximum 6 months. Treatment should not be extended beyond six months due to the risk of significant bone mineral density loss. Re-treatment courses are generally not recommended for the same reason.
Note: Add-back hormone replacement therapy may be considered by the doctor to mitigate bone loss and menopausal symptoms during treatment.
Adults – Breast Cancer (Women)
Breast Cancer (Pre-/Perimenopausal)
Dose: 3.6 mg subcutaneous implant every 28 days
Duration: Treatment continues for as long as clinically indicated, typically 2–5 years as part of adjuvant endocrine therapy. Duration is determined by the treating oncologist based on disease characteristics and response.
Adults – Uterine Fibroids (Women)
Uterine Fibroids (Pre-operative Treatment)
Dose: 3.6 mg subcutaneous implant every 28 days
Duration: Maximum 3 months. Used as pre-operative treatment to reduce fibroid size and associated bleeding before planned surgery.
Adults – Endometrial Thinning (Women)
Pre-operative Endometrial Thinning
Dose: Two 3.6 mg implants, given 28 days apart
Duration: The procedure (endometrial resection) is typically performed within 2 weeks after the second implant.
Children
Zoladex is not recommended for children and adolescents under 18 years of age. There is no established pediatric dosing for the approved indications.
Missed Dose
If you miss a scheduled Zoladex appointment, contact your healthcare provider as soon as possible to arrange a replacement injection. It is important to maintain the regular dosing schedule (every 28 days for 3.6 mg, or every 12 weeks for 10.8 mg) to ensure consistent hormone suppression. Missing doses or significantly delaying treatment may allow sex hormone levels to rise, potentially reducing the effectiveness of therapy.
Overdose
Because Zoladex is administered by healthcare professionals, overdose is extremely unlikely. In the event that an overdose occurs (for example, accidental administration of extra implants), contact your doctor, hospital, or poison control center immediately for assessment and advice. No specific antidote exists, and treatment would be supportive based on symptoms. In animal studies, high doses of goserelin produced no effects other than the expected pharmacological consequences of hormone suppression.
Do not discontinue Zoladex treatment unless your doctor instructs you to do so, even if you feel well. For conditions like prostate cancer, treatment may need to be continued long-term to maintain disease control. Stopping treatment prematurely may allow hormone levels to recover and disease to progress. Always discuss any concerns about your treatment with your doctor before making changes.
What Are the Side Effects of Zoladex?
Like all medicines, Zoladex can cause side effects, although not everyone experiences them. Most side effects are a direct consequence of the reduction in sex hormone levels and are therefore predictable and manageable. Many side effects are similar to symptoms experienced during natural menopause in women or androgen deprivation in men. It is important to discuss any side effects with your doctor, as some may require dose adjustments, additional treatments, or monitoring.
The side effects listed below are categorized by frequency and separated by sex where the profiles differ significantly. Hot flashes and sweating are the most commonly reported side effects in both men and women and may persist for several months after treatment ends.
Side Effects in Men
Very Common
Affects more than 1 in 10 patients
- Decreased sex drive (libido)
- Erectile dysfunction (impotence)
- Hot flashes and excessive sweating (may persist after treatment ends)
Common
Affects 1 in 10 to 1 in 100 patients
- Changes in blood sugar balance (glucose tolerance)
- Abnormal sensations (tingling, numbness, pins and needles)
- Spinal cord compression
- Heart failure, heart attack
- Blood pressure changes
- Skin rash
- Bone pain
- Breast enlargement (gynecomastia)
- Injection site reactions (redness, pain, swelling, bleeding)
- Decreased bone mineral density
- Weight gain
- Mood changes, depression
Uncommon
Affects 1 in 100 to 1 in 1,000 patients
- Hypersensitivity reactions
- Joint pain (arthralgia)
- Urinary tract obstruction
- Breast tenderness
Rare to Very Rare
Affects fewer than 1 in 1,000 patients
- Anaphylactic reaction (severe, rapid-onset allergic reaction)
- Pituitary tumor hemorrhage or apoplexy (in patients with pre-existing pituitary adenoma – causing severe headache, nausea, visual loss, loss of consciousness)
- Psychotic disturbances
Not Known
Frequency cannot be estimated from available data
- Hair loss (alopecia)
- QT prolongation (changes in heart rhythm on ECG)
Side Effects in Women
Very Common
Affects more than 1 in 10 patients
- Decreased sex drive (libido)
- Hot flashes and excessive sweating (may persist after treatment ends)
- Vaginal dryness
- Breast enlargement
- Injection site reactions (redness, pain, swelling, bleeding)
- Acne
Common
Affects 1 in 10 to 1 in 100 patients
- Mood changes, depression
- Abnormal sensations (tingling, numbness)
- Headache
- Blood pressure changes
- Skin rash
- Joint pain (arthralgia)
- Tumor flare (increased pain from tumor)
- Decreased bone mineral density
- Hair loss (alopecia)
- Weight gain
Uncommon
Affects 1 in 100 to 1 in 1,000 patients
- Hypersensitivity reactions
- Hypercalcemia (elevated blood calcium levels)
Rare to Very Rare
Affects fewer than 1 in 1,000 patients
- Anaphylactic reaction
- Ovarian cysts
- Ovarian hyperstimulation
- Pituitary tumor hemorrhage or apoplexy
- Psychotic disturbances
Not Known
Frequency cannot be estimated from available data
- Withdrawal bleeding (vaginal bleeding after starting treatment)
- Degeneration of uterine fibroids (in women who have them)
Contact your doctor or seek emergency medical care immediately if you experience any of the following: severe abdominal pain or abdominal swelling, shortness of breath, dizziness, decreased consciousness (possible signs of injection site vascular injury); severe headache with nausea, visual loss, or loss of consciousness (possible pituitary apoplexy); signs of a severe allergic reaction such as difficulty breathing, swelling of the face, lips, or throat, or widespread skin rash with itching.
How Should You Store Zoladex?
Zoladex should be stored at a temperature not exceeding 25°C (77°F). The product should be kept in its original outer packaging to protect it from light and moisture. The inner foil pouch is sterile and contains a desiccant; it must not be opened prior to use and should only be opened by the healthcare professional immediately before administering the injection.
Do not use Zoladex after the expiration date printed on the carton and the inner pouch after “EXP.” The expiration date refers to the last day of the stated month. Keep all medicines out of the sight and reach of children. Do not dispose of medications in wastewater or household waste. Ask your pharmacist how to properly dispose of medicines that are no longer needed, as these measures help protect the environment.
What Does Zoladex Contain?
The active substance in Zoladex is goserelin. The 3.6 mg implant contains 3.6 mg of goserelin (as goserelin acetate), while the 10.8 mg depot formulation contains 10.8 mg of goserelin. The only other ingredient is the lactide-glycolide copolymer, which forms the biodegradable matrix of the implant. This polymer gradually breaks down in the body through hydrolysis, releasing goserelin at a controlled rate throughout the dosing interval.
Zoladex is supplied as a sterile, single-use, pre-loaded syringe with a protective needle guard, packaged in a sealed aluminum foil pouch containing a desiccant. The syringe is designed for single use only and should be disposed of in a sharps container after administration. The implant itself is a small, cylindrical, white to cream-colored depot that is injected beneath the skin.
Zoladex is manufactured by AstraZeneca. It is available worldwide under the brand name Zoladex and has been used in clinical practice for over three decades since its original approval. The product is approved by the EMA (European Medicines Agency), the FDA (U.S. Food and Drug Administration), and regulatory authorities in numerous countries globally.
Frequently Asked Questions About Zoladex
Zoladex (goserelin) is a GnRH agonist used for several conditions. In men, it is primarily used for the treatment of prostate cancer, where it reduces testosterone levels to suppress tumor growth. In women, Zoladex is used for endometriosis (uterine lining tissue growing outside the uterus), hormone receptor-positive breast cancer (in pre- and perimenopausal women), uterine fibroids (to reduce bleeding and pain before surgery), and as a pre-operative treatment before endometrial resection. It works by suppressing the pituitary gland, which leads to reduced levels of sex hormones.
Zoladex is administered as a subcutaneous implant injected into the front of the abdominal wall below the navel. The injection must be performed by a healthcare professional (doctor or nurse) and cannot be self-administered. The 3.6 mg implant is given every 28 days, while the 10.8 mg depot formulation is given every 12 weeks. The implant slowly dissolves in the body, releasing goserelin at a controlled rate throughout the dosing period.
The most common side effects affect more than 1 in 10 patients and are related to hormone suppression. In both men and women, hot flashes (sudden feelings of warmth, often with sweating) and decreased sex drive are very common. Men may also experience erectile dysfunction (impotence). Women may experience vaginal dryness, breast enlargement, and acne. These effects are generally reversible after treatment ends, though hot flashes may persist for several months after stopping Zoladex.
Yes, Zoladex can reduce bone mineral density (cause bone thinning) because it lowers sex hormone levels, which are important for maintaining bone health. This is a recognized side effect that occurs in both men and women during treatment. In women treated for endometriosis, treatment duration is limited to 6 months partly for this reason. Some bone recovery may occur after treatment is discontinued. Your doctor may recommend bone density monitoring, calcium and vitamin D supplementation, or other medications to protect bone health during long-term treatment.
When Zoladex treatment begins, it initially causes a temporary increase in testosterone (in men) or estrogen (in women) for the first 1–2 weeks before suppression occurs. In men with prostate cancer, this initial surge can temporarily worsen symptoms such as bone pain, difficulty urinating, or in rare cases spinal cord compression. This is called the “tumor flare” effect. Doctors typically prescribe an antiandrogen medication (such as bicalutamide) to be taken before and during the first few weeks of Zoladex treatment to counteract this effect. After 2–3 weeks, hormone levels fall below baseline and remain suppressed.
No, Zoladex must not be used during pregnancy or breastfeeding. Women of childbearing potential must use non-hormonal contraception (barrier methods or IUD) during treatment. Oral contraceptive pills should not be used as they may be less effective during Zoladex therapy. If pregnancy occurs during treatment, the patient should inform her doctor immediately, as there is a theoretical risk of miscarriage or fetal abnormality.
References
- European Medicines Agency (EMA). Zoladex – Summary of Product Characteristics. Last updated 2024. Available from: www.ema.europa.eu
- U.S. Food and Drug Administration (FDA). Zoladex (goserelin acetate implant) – Prescribing Information. AstraZeneca. Revised 2024.
- National Comprehensive Cancer Network (NCCN). NCCN Clinical Practice Guidelines in Oncology: Prostate Cancer. Version 4.2025. Available from: www.nccn.org
- European Association of Urology (EAU). EAU-EANM-ESTRO-ESUR-ISUP-SIOG Guidelines on Prostate Cancer. 2025 Update. Available from: uroweb.org/guidelines
- Bolla M, et al. Long-term results with immediate androgen suppression and external irradiation in patients with locally advanced prostate cancer (an EORTC study): a phase III randomised trial. Lancet. 2002;360(9327):103–108.
- Pagani O, et al. Adjuvant exemestane with ovarian suppression in premenopausal breast cancer (SOFT and TEXT trials). N Engl J Med. 2014;371(2):107–118.
- European Society of Human Reproduction and Embryology (ESHRE). ESHRE Guideline: Endometriosis. 2022. Available from: www.eshre.eu
- British National Formulary (BNF). Goserelin. National Institute for Health and Care Excellence (NICE). Updated 2025. Available from: bnf.nice.org.uk
- World Health Organization (WHO). WHO Model List of Essential Medicines. 23rd List, 2023. Geneva: WHO.
- Keating NL, et al. Diabetes and cardiovascular disease during androgen deprivation therapy for prostate cancer. J Clin Oncol. 2006;24(27):4448–4456.
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