BMA Concise Guide to Medicine & Drugs

Goserelin

Brand names Zoladex, Zoladex LA

Used in the following combined preparations None

QUICK REFERENCE

Drug group Anticancer drug

Overdose danger rating Low

Dependence rating Low

Prescription needed Yes

Available as generic No

GENERAL INFORMATION

Goserelin is a synthetic analogue of the hormone gonadorelin (now more commonly known as gonadotrophin-releasing hormone, or GnRH). Like GnRH, it stimulates the release of other hormones from the pituitary gland, which in turn control production of sex hormones. Goserelin reduces testosterone levels in men and oestrogen levels in premenopausal women, and is used to treat prostate cancer in men and breast cancer in women. At the start of treatment for prostate cancer, it is often given with an anti-androgen drug to control an initial growth spurt of the tumour – known as ‘tumour flare’. The drug is also used in the management of fibroids, endometriosis, and assisted reproduction. The first dose is normally given during menstruation to avoid the possibility that the patient may be pregnant. Women of childbearing age are advised to use barrier methods of contraception during treatment.

Loss of bone density is an important side effect in women. Therefore, repeat courses of the drug are given only for cancerous conditions.

INFORMATION FOR USERS

Your drug prescription is tailored for you. Do not alter dosage without checking with your doctor.

How taken/used Implant injection, long-acting implant injection.

Frequency and timing of doses Endometriosis Every 28 days, maximum of a single 6-month treatment course only (implant). Fibroids Every 28 days, maximum 3 months’ treatment (implant). Breast and prostate cancer Every 28 days. Prostate cancer Every 12 weeks (LA implant).

Adult dosage range 3.6mg (implant) every 28 days (endometriosis/fibroids/breast and prostate cancer); 10.8mg (LA implant) every 3 months.

Onset of effect Within 24 hours (endometriosis/fibroids/breast cancer); 1–2 weeks after tumour flare (prostate).

Duration of action 28 days (implant); 12 weeks (long-acting implant).

Diet advice None.

Storage Not applicable. The drug is not kept at home.

Missed dose No cause for concern. Treatment can be resumed when possible.

Stopping the drug Do not stop treatment without consulting your doctor.

Exceeding the dose Overdosage is unlikely since treatment is not self-administered.

POSSIBLE ADVERSE EFFECTS

Symptoms similar to those of the menopause in women or orchidectomy (removal of the testes) in men are common. Such symptoms include hot flushes, sweating, reduced libido, erectile dysfunction (in men), and breast enlargement and tenderness. There may also be bone pain, and some women experience vaginal bleeding during the early stages of treatment. More rarely, the drug may cause rash, wheezing, a reaction at the injection site, dizziness, fainting, and ovarian cysts (in women). Any such effects should be reported to your doctor straight away.

INTERACTIONS

Antidiabetic drugs Goserelin may reduce the blood-sugar-lowering effect of these drugs.

SPECIAL PRECAUTIONS

Be sure to tell your doctor if:

· You have osteoporosis.

· You have diabetes.

· You have previously been treated with goserelin (or another gonadorelin analogue) for endometriosis or fibroids.

· You have polycystic ovarian disease.

· You are allergic to gonadorelin analogues.

· You are taking other medicines.

Pregnancy Not prescribed. Risk of harm to the fetus.

Breast-feeding Not recommended. Discuss with your doctor.

Infants and children Not recommended.

Over 60 No special problems.

Driving and hazardous work No special problems.

Alcohol No special problems.

PROLONGED USE

Goserelin is only used in the long term for treatment of prostate or breast cancer. Bone density may be lost, and medication to counteract this may be given.

Monitoring Women are usually monitored for changes in bone density.