How does it work?

Zoladex LA implant contains the active ingredient goserelin acetate, which is a type of medicine known as a gonadorelin (LHRH) analogue. It acts on the pituitary gland in the brain.

The pituitary gland produces and stores various hormones, including the sex hormones, luteinising hormone (LH) and follicle-stimulating hormone (FSH). In men, LH causes the testicles to produce testosterone. FSH and testosterone cause the production of sperm by the testicles.

The amount of LH and FSH released from the pituitary gland is controlled by another hormone, called gonaderelin (LHRH). Gonadorelin acts on LHRH receptors in the pituitary gland, causing the release of LH and FSH and hence the subsequent production of testosterone in men.

Goserelin acetate is a synthetic form of gonaderelin. It acts on the LHRH receptors in the pituitary gland, in the same way as natural gonadorelin.

Initially, goserelin causes an increase in the amount of FSH and LH released from the pituitary gland. However, chronic administration of goserelin desensitises the pituitary gland. This means that it produces less and less FSH and LH, which in turn stops the production of testosterone in men.

The growth of some prostate cancers is stimulated by testosterone. Reducing the body's levels of testosterone therefore deprives the tumour of testosterone and causes it to shrink. This treatment does not provide a cure, but rather improves quality of life and increases life expectancy.

The Zoladex LA implant is injected under the skin of the abdomen, from where it steadily releases the goserelin into the bloodstream over a 12 week period. An implant is injected every 12 weeks.

What is it used for?

• Prostate cancer.

Warning!

• Goserelin may cause an initial temporary tumour 'flare' with symptoms such as urinary obstruction and bone pain, before the cancer begins to shrink. Some men may be particularly prone to these symptoms. If this applies to you, your doctor will also treat you with another type of anti-cancer medicine, known as an anti-androgen (eg cyproterone acetate or flutamide) to prevent this. The anti-androgen will be started three days before the goserelin and continued for the first three weeks of treatment.
• Your doctor may want to monitor your blood sugar levels while you are being treated with this medicine.

Use with caution in

• Men considered by their doctor to be at risk of an initial worsening of their tumour symptoms (tumour flare) when starting treatment.
• Men whose cancer has spread to the spine.
• Men with difficulty passing urine.
• Diabetes.
• Metabolic bone disease, eg osteoporosis (this medicine may cause a reduction in bone mineral density).

Not to be used in

• Women.
• Children.
• Allergy to other LHRH analogues, eg buserelin, leuprorelin, triptorelin.

This medicine should not be used if you are allergic to one or any of its ingredients. Please inform your doctor or pharmacist if you have previously experienced such an allergy.If you feel you have experienced an allergic reaction, stop using this medicine and inform your doctor or pharmacist immediately.

Side effects

Medicines and their possible side effects can affect individual people in different ways. The following are some of the side effects that are known to be associated with this medicine. Just because a side effect is stated here does not mean that all people using this medicine will experience that or any side effect.

• Bruising or pain at injection site.
• Temporary increase in bone pain, pain in your lower back, or difficulty passing urine. Tell your doctor if this happens.
• Hot flushes.
• Decreased sex drive.
• Breast swelling and tenderness.
• Sweating.
• Skin rashes.
• Pins and needles sensations (paraesthesia).
• Pain in the joints (arthralgia).
• Decrease in bone mineral density.
• Changes in blood pressure.
• Increase in blood sugar levels.
• Rarely, allergic reactions.
• Very rarely, damage to the pituitary gland due to sudden haemorrhage or decreased blood supply (pituitary apoplexy) following initial administration.

The side effects listed above may not include all of the side effects reported by the medicine's manufacturer.For more information about any other possible risks associated with this medicine, please read the information provided with the medicine or consult your doctor or pharmacist.

How can this medicine affect other medicines?

This medicine is not known to affect other medicines. However, as with all medicines, it is important to let your doctor or pharmacist know what medicines you are already taking, including those bought without a prescription and herbal medicines, before you start treatment with this medicine. Similarly, always check with your doctor or pharmacist before using other medicines while being treated with this one, to make sure the combination is safe.

Other medicines containing the same active ingredient