Suprefact (buserelin)

How does it work?

Suprefact injection and nasal spray both contain the active ingredient buserelin, 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 released from the pituitary gland 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.

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

Initially, buserelin causes an increase in the amount of FSH and LH released from the pituitary gland, with a resulting increase in testosterone production. However, chronic administration of buserelin 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. This reduction in the level of testosterone caused by buserelin is used to treat prostate cancer.

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. Treatment is started with buserelin injection, which is administered under the skin (subcutaneously) every eight hours for seven days. After this, the treatment is continued with buserelin nasal spray, used six times a day in each nostril. The medicine is absorbed into the bloodstream through the rich supply of blood vessels found in the lining of the nose. The medicine is absorbed even if you have a cold.

As the buserelin may at first increase testosterone levels, it 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 buserelin and continued for the first two to three weeks of treatment.

What is it used for?

Advanced prostate cancer in men.

Warning!

This medicine may cause side effects such as dizziness and blurred vision that could reduce your ability to drive or operate machinery safely. Do not drive or operate machinery until you know how this medicine affects you and you are sure it won't affect your performance.

The amount of testosterone in your blood should be measured before you start treatment with this medicine and every three months during treatment.

People with diabetes should monitor their blood sugar carefully during treatment with this medicine.

People with high blood pressure (hypertension) should have their blood pressure monitored regularly during treatment with this medicine.

Use with caution in

Depression

Diabetes

High blood pressure

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 or other bones

Men with difficulty passing urine.

Not to be used in

Men who have had their testicles surgically removed (orchidectomy)

Tumours found to be insensitive to hormone manipulation.

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. Because a side effect is stated here, it does not mean that all people using this medicine will experience that or any side effect.

Nasal irritation, nose bleeds, hoarseness and taste or smell disturbances (only applicable to the nasal spray)

Disturbances of the gut such as diarrhoea, constipation, nausea, vomiting or abdominal pain

Dizziness

Headache

Sleep disturbances

Tiredness

Appetite and weight changes

Dry skin or eyes

Increase or decrease in scalp and body hair

Awareness of your heartbeat (palpitations)

Hot flushes

Fluid retention, causing swelling (oedema)

Increased thirst

Nervousness or anxiety

Depression

Concentration or memory difficulties

Visual disturbances

Enlargement of breasts (gynaecomastia)

Decreased sex drive

Blood disorders

The side effects listed above may not include all of the side effects reported by the drug'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?

It is important to tell your doctor or pharmacist what medicines you are already taking, including those bought without a prescription and herbal medicines, before you start treatment with this medicine. Similarly, check with your doctor or pharmacist before taking any new medicines while having treatment with this one, to ensure that the combination is safe.

If you are also using nasal decongestant drops or spray, for example to relieve a blocked nose during a cold, this should be administered at least 30 minutes after your buserelin nasal spray.

If you have diabetes, your dose of insulin or antidiabetic tablets may need to be increased while you are taking this medicine. You should monitor your blood sugar and seek advice from your doctor or pharmacist if your blood sugar control seems to be altered after starting treatment.

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