Generic Name: Goserelin

Drug Type:

Zoladex is a hormone therapy.  It is classified as an "LHRH agonist." (For more detail, see "How Zoladex Works" section below).

What Zoladex Is Used For:

• Prostate cancer
• Breast cancer
• Also used to treat endometriosis (non-cancerous condition)

Note: If a drug has been approved for one use, physicians may elect to use this same drug for other problems if they believe it may be helpful.

How Zoladex Is Given:

• Injection under the skin (subcutaneous, SubQ)
• As a monthly or every 3 month injection
• Your doctor will determine your dose and schedule

Side Effects:

Important things to remember about the side effects of Zoladex:

• Most people do not experience all of the side effects listed.
• Side effects are often predictable in terms of their onset and duration.
• Side effects are almost always reversible and will go away after treatment is complete.
• There are many options to help minimize or prevent side effects.
• There is no relationship between the presence or severity of side effects and the effectiveness of the medication.

The following side effects are common (occurring in greater than 30%) for patients taking Zoladex:

• Hot flashes (see sexuality)
• Loss of libido (decreased interest in sex)
• Impotence (inability to obtain or sustain an erection)

These side effects are less common side effects (occurring in about 10-29%) of patients receiving Zoladex:

• Increased bone pain due to disease "flare" during first couple weeks of treatment
• Headache 
• Vaginal dryness (see sexuality)
• Swelling of the breasts (gynecomastia) (see sexuality) 
• Depression
• Sleepiness
• Skin rash

Zoladex may cause short-term (within first 2 weeks of treatment) increases in testosterone serum levels.  When this is used for prostate cancer the resulting "tumor flare" can cause temporary increase of bone pain, swelling of the prostate that blocks urine flow or swelling around tumor in the spine causing compression of the spinal cord. If you are noticing increased weakness, numbness or tingling in arms or legs, or difficulty with urination, report these symptoms to your health care provider immediately.

Rare but significant side effects may include heart problems such as arrhythmias, congestive heart failure or heart attack (<5%).

Not all side effects are listed above. Some that are rare (occurring in less than 10% of patients) are not listed here.  However, you should always inform your health care provider if you experience any unusual symptoms.

When to contact your doctor or health care provider:

Contact your health care provider immediately, day or night, if you should experience any of the following symptoms:

• Urinary retention or inability to urinate
• Weakness, numbness or tingling in arms or legs

The following symptoms require medical attention, but are not an emergency.  Contact your health care provider within 24 hours of noticing any of the following:

• Extreme fatigue (unable to carry on self-care activities)
• Swelling of the feet or ankles.  Sudden weight gain.
• Swelling, redness and/or pain in one leg or arm and not the other
• Changes in mood or memory

Always inform your health care provider if you experience any unusual symptoms.

Precautions:

• Before starting Zoladex treatment, make sure you tell your doctor about any other medications you are taking (including prescription, over-the-counter, vitamins, herbal remedies, etc.).  
• Inform your health care professional if you are pregnant or may be pregnant prior to starting this treatment. Pregnancy category X (Zoladex may cause fetal harm when given to a pregnant woman.  Zoladex must not be given to a pregnant woman or a woman who intends to become pregnant.  If a woman becomes pregnant while taking Zoladex, the medication must be stopped immediately and the woman given appropriate counseling).
• For both men and women: Do not conceive a child (get pregnant) while taking Zoladex.  Barrier methods of contraception, such as condoms, are recommended. Discuss with your doctor when you may safely become pregnant or conceive a child after therapy.
• Do not breast feed while taking Zoladex.

Self-Care Tips:

• If you are experiencing hot flashes, wearing light clothing, staying in a cool environment, and putting cool cloths on your head may reduce symptoms. Consult your health care provider if these worsen, or become intolerable.
• Avoid sun exposure.  Wear SPF 15 (or higher) sunblock and protective clothing.
• In general, drinking alcoholic beverages should be kept to a minimum or avoided completely.  You should discuss this with your doctor.
• Get plenty of rest. 
• Maintain good nutrition.
• If you experience symptoms or side effects, be sure to discuss them with your health care team.  They can prescribe medications and/or offer other suggestions that are If you experience symptoms or side effects, be sure to discuss them with your health care team.  They can prescribe medications and/or offer other suggestions that are effective in managing such problems.

Monitoring and Testing:

You will be checked regularly by your health care professional while you are taking Zoladex, to monitor side effects and check your response to therapy.  Periodic blood work to monitor your complete blood count (CBC) as well as the function of other organs (such as your kidneys and liver) may also be ordered by your doctor.   

How Zoladex Works:

Hormones are chemical substances that are produced by glands in the body, which enter the bloodstream and cause effects in other tissues.  For example, the hormone testosterone, made in the testicles and is responsible for male characteristics such as deepening voice and increased body hair.  The use of hormone therapy to treat cancer is based on the observation that receptors for specific hormones that are needed for cell growth are on the surface of some tumor cells.  Hormone therapy can work by stopping the production of a certain hormone, blocking hormone receptors, or substituting chemically similar agents for the active hormone, which cannot be used by the tumor cell. Different types of hormone therapies are categorized by their function and/or the type of hormone that is affected.

Zoladex is classified as a luteinizing hormone releasing hormone (LHRH) agonist.

LHRH agonists work by telling the pituitary gland located in the brain to stop producing luteinizing hormone, which (in men) stimulates the testicles to release testosterone and (in women) stimulates the ovaries to release estrogen.  The drug does not have a direct effect on the cancer, only on the testicles or ovaries. The resulting lack of testosterone (in men) and estrogen (in women) interferes with stimulating cell growth in testosterone or estrogen dependent cancer cells.

In treatment of prostate cancer LHRH agonists are often used together with anti-androgen medications. Anti-androgens are substances that block the effects of testosterone. Cancer of the prostate depends on the male hormone testosterone for its growth.  If the amount of testosterone is reduced it is possible to slow down or shrink the cancer.

• Examples of anti-androgens are: bicalutamide, flutamide, nilutamide.

Note: We strongly encourage you to talk with your health care professional about your specific medical condition and treatments. The information contained in this website is meant to be helpful and educational, but is not a substitute for medical advice.

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