Zoladex (goserelin) is an artificial form of hormone that controls many processes in the body. Goserelin over-stimulates the production of some hormones in the body, which leads to temporary stop of production. Zoladex implants are recommended by doctors to treat symptoms of prostate cancer in men.
This implant is also used in women to treat breast cancer or endometriosis. It can be used in women to prepare the lining of the uterus for endometrial ablation (a surgery to fix abnormal uterine bleeding). In some cases, Zoladex is used with other cancer drugs like flutamide.
Goserelin has negative effects on an unborn baby, and it can lead to birth defects. Do not use Zoladex during pregnancy, except you’re treating breast cancer. You can use effective and non-hormonal (barrier) birth control during treatment and for at least 12 weeks after treatment ends. Let your doctor know about any pregnancy during treatment. Avoid breastfeeding when using this implant.
Do not use Zoladex if you are allergic to goserelin or to other hormone drugs such as leuprolide (Lupron, Eligard, Viadur), nafarelin (Synarel), or ganirelix (Antagon).
You should tell your doctor if you have an underlying issue such as diabetes, osteoporosis, urination problems, high blood pressure, high cholesterol,  smoking, overweight and spine problems before getting Zoladex.
Zoladex can lower bone mineral density, which may increase your risk of having osteoporosis.
Call your doctor at once if you experience any severe side effect while using Zoladex, which include:
- Severe numbness or tingling in your legs or feet
- Muscle weakness
- Problems with balance or coordination
- Loss of bladder or bowel control
- Urinating less than usual
- Pain or burning when you urinate
- Blood in your urine or stools
- Easy bruising
- Increased thirst or urination
- Fruity breath odor
- Trouble breathing
- Sudden numbness or weakness
- Sudden severe headache, confusion
- Problems with vision or speech
- Chest pain spreading to the arm or shoulder
You can use a non-hormonal type of birth control (condom, diaphragm, cervical cap, contraceptive sponge) to stop pregnancy while the Zoladex implant has been inserted.
Use birth control for at least 12 weeks after removing the implant. The Zoladex implant can stop ovulation and menstrual periods, but you could still get pregnant. Keep using birth control for at least 12 weeks after the implant was removed. Even though the Zoladex implant can stop ovulation and menstrual periods, you could still become pregnant.
Your doctor should be aware of you have ever had these conditions, before using the implant:
- Diabetes 
- Heart problems, heart attack, or stroke 
- Bone cancer 
- Long QT syndrome (in you or a family member)
- Low bone mineral density (osteoporosis)
- Abnormal vaginal bleeding that has not been checked by a doctor.
Goserelin can reduce bone mineral density, which may increase your risk of having osteoporosis. This risk is greater in people who smoke, drink alcohol regularly, have a family history of osteoporosis, or use certain drugs such as seizure medicine or steroids.  Talk to your doctor about your individual risk that you already know.