Goserelin Implant: What It Treats, How It Is Given, Side Effects
Last updated September 6, 2026.
**Goserelin is a gonadotropin-releasing hormone (GnRH) agonist, given as a small implant placed under the skin, that lowers the sex hormones your body makes.** It works on the pituitary gland. After a brief surge, it shuts down the signal that tells the testicles to make testosterone or the ovaries to make estrogen, which slows hormone-driven cancers and quiets endometriosis tissue. The most important safety point is that the first few weeks can cause a temporary hormone surge called tumor flare, so new bone pain, trouble passing urine, or leg weakness and numbness in that window needs medical attention right away.
What does it treat?
Goserelin is used for advanced prostate cancer, where it lowers testosterone as an alternative to surgical removal of the testicles, and it is used with radiation therapy in locally confined higher-risk prostate cancer. In premenopausal and perimenopausal women it treats advanced breast cancer that responds to hormone therapy. It also treats endometriosis, including the pelvic pain, painful periods, and pain with sex that come with it, and it is used to thin the uterine lining before endometrial ablation for heavy bleeding. In prostate cancer, it is often paired with an antiandrogen such as bicalutamide or flutamide, especially in the first weeks, and in breast cancer it is commonly combined with tamoxifen or an aromatase inhibitor.
How do you take it?
Goserelin is not a pill and you do not give it to yourself. A clinician injects a preloaded implant just under the skin of your upper belly wall, usually after numbing the spot, and it slowly releases the drug. The 3.6 mg implant is given every 28 days for prostate cancer, breast cancer, and endometriosis. The 10.8 mg implant is given every 12 weeks and is used for prostate cancer. For endometriosis, treatment is limited to 6 months in a single course because of bone loss, and for thinning the uterine lining before ablation you get one implant, or two implants 4 weeks apart, with surgery timed a few weeks later. The ceiling is one implant per scheduled interval, so never get an extra implant to make up for a late one. There are no food or drink restrictions and no need to time it around meals. If you miss your appointment, call the office as soon as you notice and get rebooked within a few days, since hormone levels start to climb back once the interval runs out. Call your doctor before your next implant if you have new bone pain, trouble urinating, leg weakness, mood changes that worry you, or blood sugar readings that are climbing.
Side effects to know
- Common: Most people get hot flashes and sweating, and many also notice lower sex drive, trouble with erections or vaginal dryness, headache, mood swings, acne, weight change, and soreness or bruising where the implant went in.
- Serious: Get help right away for signs of a serious allergic reaction, such as hives, swelling of the face, lips, or throat, or trouble breathing, and for spinal cord compression signaled by new leg weakness, numbness, or loss of bladder or bowel control. Also call urgently for inability to pass urine or severe flank pain, chest pain or stroke symptoms, and heavy bleeding, swelling, or severe pain at the implant site.
Who should not take it?
Do not use goserelin if you have had an allergic reaction to it or to another GnRH agonist such as leuprolide, and do not use it for endometriosis or endometrial thinning if you are pregnant, since it can harm the fetus and is contraindicated in pregnancy for those uses. Pregnancy must be ruled out before starting, and you should use a nonhormonal barrier method during treatment and for 12 weeks after the last implant, because periods stopping does not prove ovulation has stopped. Do not breastfeed while receiving it or for 12 weeks after the last dose. Tell your doctor first if you have osteoporosis or low bone density, a family history of it, diabetes or prediabetes, heart disease, a prior heart attack or stroke, a long QT interval or a history of abnormal heart rhythms, a bleeding disorder, or if you take blood thinners such as warfarin, apixaban, or rivaroxaban, since injecting the implant can injure a blood vessel in the abdominal wall. Also mention drugs that affect heart rhythm, such as amiodarone, sotalol, or certain antipsychotics, and long-term steroids or seizure medicines that weaken bone. There is no direct alcohol interaction, but heavy or daily drinking and smoking speed up bone loss during treatment, so keep alcohol light or skip it.
When is it an emergency?
Call 911 in the US for trouble breathing, swelling of the face, lips, or tongue, fainting or collapse, chest pain, or sudden weakness, drooping, or trouble speaking. Go to an emergency department for new weakness or numbness in the legs, loss of bladder or bowel control, or back pain that will not let up, since these can mean the spinal cord is being pressed on, and for not being able to pass urine at all or severe one-sided flank pain. Go in the same day for bleeding, a spreading bruise, a hard swelling, or severe pain at the implant site in your belly, especially if you take a blood thinner and you feel dizzy or lightheaded. For a suspected overdose or a wrong implant strength, call Poison Control at 1-800-222-1222; there is no specific antidote, and care is based on your symptoms.
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Common questions
What is the maximum dose of goserelin I can get?
There is no daily dose to add up, because the implant releases drug slowly over its whole interval. The limit is one implant per scheduled interval: 3.6 mg every 28 days, or 10.8 mg every 12 weeks for prostate cancer. Never get a second implant early to make up for a late appointment. For endometriosis and for thinning the uterine lining before ablation, there is also a course limit, since endometriosis treatment is capped at 6 months in one course because of bone loss. If a repeat course is being considered, your doctor should check your bone density first.
Can I drink alcohol while I am on goserelin?
There is no direct interaction between alcohol and goserelin, and an occasional drink will not change how the implant works. The real issue is bone. Goserelin lowers estrogen or testosterone, which thins bone over months, and heavy or daily drinking adds to that loss. Smoking does the same. Keeping alcohol light, staying active with weight-bearing exercise, and getting enough calcium and vitamin D protect your bones during treatment.
What happens if I get pregnant on goserelin?
Stop treatment and tell your doctor right away. Goserelin can harm a developing fetus, and it is contraindicated in pregnancy when used for endometriosis or for thinning the uterine lining. Your periods usually stop during treatment, but that does not mean you cannot ovulate, so pregnancy can happen. Use a nonhormonal barrier method the whole time you are on it and for 12 weeks after your last implant. Do not breastfeed during treatment or for 12 weeks after the last dose.
Do I need to take it with food or avoid anything I eat?
No. The implant goes under the skin of your upper abdominal wall, so nothing about food, timing of meals, or grapefruit matters. You can eat and drink normally on the day of your appointment. The one diet point worth attention is calcium and vitamin D, since long-term treatment lowers bone density. Ask your doctor whether you should be taking a supplement and whether you are due for a bone density scan.
What are signs of a problem after my implant is placed?
Overdose from a slow-release implant is uncommon, and if a wrong strength was placed, call Poison Control at 1-800-222-1222, since there is no antidote and treatment is based on symptoms. In the first weeks of prostate cancer treatment, watch for tumor flare: new or worse bone pain, trouble starting or passing urine, and leg weakness or numbness. Leg weakness, numbness, or losing control of your bladder or bowel is an emergency. At the implant site itself, heavy bleeding, a spreading bruise, or severe belly pain needs to be seen the same day, especially if you take a blood thinner.
What medicines interact with goserelin?
Tell your doctor about blood thinners such as warfarin, apixaban, or rivaroxaban, and about any bleeding disorder, because placing the implant can injure a blood vessel in the abdominal wall. Drugs that can lengthen the QT interval, including amiodarone, sotalol, and some antipsychotics and antibiotics, matter because androgen deprivation can prolong QT on its own. Long-term corticosteroids and some seizure medicines add to bone loss. Goserelin also raises blood sugar, so if you take insulin or other diabetes medicines your doses may need adjusting. It is often given on purpose with an antiandrogen, tamoxifen, or an aromatase inhibitor, which is a planned combination, not an interaction.