Short answer: In the Zoladex 3.6 mg label, men with advanced prostate cancer most often had hot flashes (62% vs 53% after orchiectomy), sexual dysfunction (21%) and decreased erections (18%). Women treated for endometriosis most often had hot flushes (96%), vaginitis (75%), headache (75%), decreased libido (61%) and emotional lability (60%). It has no boxed warning; its warnings include tumor flare, bone loss and injection site injury.
What Zoladex 3.6 mg is approved for: Zoladex 3.6 mg is a GnRH agonist approved, with flutamide, for locally confined stage B2-C prostate cancer; for palliative treatment of advanced prostate cancer; for endometriosis; for thinning the uterine lining before endometrial ablation for dysfunctional uterine bleeding; and for palliative treatment of advanced breast cancer in pre- and perimenopausal women (sections 1.1 to 1.5). The 10.8 mg 3-month implant is a separate label.
Source
ZOLADEX (goserelin implant) 3.6 mg, for subcutaneous use, prescribing information. TerSera Therapeutics. DailyMed, version published March 26, 2026. DailyMed setid 294b168b-6e5f-4db9-bf70-d599271458b3
No. The current Zoladex 3.6 mg label has no boxed warning.
These are the label's own numbers from the Adverse Reactions section. Where the label compares with placebo (a dummy treatment), both columns are shown, so you can see how much more often a reaction happened on Zoladex 3.6 mg.
| Adverse event | ZOLADEX (%) n=242 | ORCHIECTOMY (%) n=254 |
|---|---|---|
| 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 | 18 |
Orchiectomy is surgical removal of the testicles, a comparison treatment rather than placebo. Surgical complications were reported in 18% of orchiectomy patients; 3% of Zoladex patients reported injection site reactions.
| Adverse event | ZOLADEX (%) n=411 | DANAZOL (%) n=207 |
|---|---|---|
| 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 |
| Insomnia | 11 | 4 |
Danazol is another endometriosis medicine used as a comparator; there was no placebo group. Rows shown are those at 10% or more on Zoladex.
| Adverse event | ZOLADEX 3.6 mg (%) n=180 | Placebo (%) n=177 |
|---|---|---|
| Vasodilatation | 57 | 18 |
| Headache | 32 | 22 |
| Sweating | 16 | 5 |
| Abdominal Pain | 11 | 10 |
| Pelvic Pain | 9 | 6 |
| Migraine | 7 | 4 |
| Hypertension | 6 | 2 |
| Dysmenorrhea | 7 | 9 |
| Pharyngitis | 6 | 9 |
| Uterine Hemorrhage | 6 | 4 |
| Vulvovaginitis | 5 | 1 |
| Nausea | 5 | 6 |
| Nervousness | 5 | 3 |
Premenopausal women with dysfunctional uterine bleeding given two Zoladex 3.6 mg implants or two placebo injections before endometrial ablation. Rows shown are those at 5% or more on Zoladex. Vasodilatation means hot flushes.
| Adverse event | ZOLADEX (% of pts.) n=57 | OOPHORECTOMY (% of pts.) n=55 |
|---|---|---|
| Hot Flashes | 70 | 47 |
| Tumor Flare | 23 | 4 |
| Nausea | 11 | 7 |
| Edema | 5 | 0 |
| Malaise/Fatigue/Lethargy | 5 | 2 |
| Vomiting | 4 | 7 |
Pre- and perimenopausal women. Oophorectomy is surgical removal of the ovaries.
After 6 months of Zoladex, 109 women had an average 4.3% drop in spine bone density. It was still down 2.4% 6 months after stopping (66 women) and 2.5% at 12 months after stopping (28 women), suggesting possible partial recovery.
With flutamide and radiation for stage B2-C prostate cancer, events in more than 5% over the whole study were hot flashes (46%), diarrhea (40%), nausea (9%) and skin rash (8%).
In 333 pre- and perimenopausal women with advanced breast cancer in Phase II trials, hot flashes were reported in 75.9% and decreased libido in 47.7%. Injection site reactions were under 1%.
In endometriosis patients at 6 months, LDL cholesterol rose 21.3 mg/dL and HDL rose 2.7 mg/dL on Zoladex, vs LDL up 33.3 and HDL down 21.3 on danazol. Raised liver enzymes were seen in under 1% of women.
Reported after approval: bone loss and fractures in men, blood clots, heart attack and stroke in women on GnRH agonists (causal link unknown), ovarian cysts, blood pressure changes, pituitary apoplexy (mostly within 2 weeks of the first dose), severe skin reactions, mood swings, suicidal thoughts and convulsions.
The Warnings and Precautions part of the label lists these. Each line gives the label's heading and what it means in plain words.
Pregnancy and contraception. Pregnancy is excluded before use for benign gynecologic conditions. Premenopausal women use effective nonhormonal contraception during treatment and for 12 weeks after stopping; Zoladex usually stops ovulation but does not ensure pregnancy prevention. It can cause fetal harm.
Tumor flare. Testosterone (in men) or estrogen (in women) rises briefly at first, so cancer symptoms such as bone pain may worsen in the first weeks. Isolated cases of ureteral blockage and spinal cord compression have occurred in prostate cancer.
Diabetes and heart risk in men. High blood sugar, a higher risk of diabetes, and a small increased risk of heart attack, sudden cardiac death and stroke have been reported in men on GnRH agonists. Blood sugar or HbA1c and heart symptoms are monitored.
High calcium. High blood calcium has been reported in some prostate and breast cancer patients with bone metastases after starting Zoladex.
Allergic and severe skin reactions. Allergic reactions, antibodies and anaphylaxis have been reported with GnRH agonists. Severe skin reactions including SJS/TEN, DRESS and AGEP can occur; Zoladex is paused if one is suspected and stopped for good if confirmed.
Cervix and QT interval. Zoladex may make the cervix harder to dilate before endometrial ablation. Androgen deprivation therapy may prolong the QT interval, which is weighed in people with heart rhythm risks.
Injection site and blood vessel injury. Pain, bruising, bleeding and hemorrhagic shock needing transfusion or surgery have been reported. Extra care is taken in people with low BMI or on full-dose blood thinners.
Depression. Depression may start or worsen in women on Zoladex 3.6 mg, especially with a history of depression. New or worsening depression may lead to referral to a mental health professional.
From the Patient Counseling Information (section 17) that comes with Zoladex 3.6 mg:
Dose Track has a side-effect log. Each entry records the symptom, a severity (none, mild, moderate, severe or life-threatening), the date and an optional note, and can be tied to a specific dose or logged on its own. The history screen shows what you logged over time, which makes it easier to tell your prescriber when a reaction started and whether it is easing. The app records what you enter; it does not judge whether a symptom is serious. For anything on the label's call-your-doctor list, call your doctor.
This page is what the FDA label says, in plain words. It is not medical advice. Follow your prescriber, and ask them or your pharmacist about anything here.