GnRH Analogues

What is a GnRH Analogue?

A GnRH analogue is a medication which suppresses the release of oestrogen from the

ovaries and causes a temporary and reversible ‘menopause’.

How does it work?

GnRH analogues are similar to a hormone already produced in humans called Gonadotrophin Releasing Hormone (GnRH). GnRH controls the production of the female reproductive hormones, oestrogen and progesterone. By giving the GnRH analogue, we temporarily “switch off” ovarian activity, this switches off the production of hormones and thus periods for the duration of treatment.

How and when is it given?

GnRH Analogues are either given by injection under the skin (subcutaneously), most commonly into the abdominal wall, or as an intramuscular injection in the thigh or buttock. GnRH Analogues are usually given every 4 weeks or 3 monthly in an outpatient setting by a nurse or doctor. Certain preparations (Nafarelin) can be self-administered as a nasal spray.

Treatment length

This medication is licensed for up to 6 months. If necessary, continuing this medication for longer than 6 months may be considered by the clinician looking after you. Treatment with GnRH analogues beyond 6 months will require Hormone Replacement Therapy (HRT) to avoid bone thinning which can happen with prolonged use of GnRH analogues. Sometimes the clinician may start HRT sooner than 6 months or at the commencement of the GnRH analogues. In addition to prevention of bone thinning, HRT is likely to minimise the menopausal symptoms (described under the side effects) associated with GnRH analogues.

If you do take the GnRH-a medication for more than 6–12 months without HRT, you may be recommended to have a bone density test. This is called DXA scan (Dual Energy Xray Absorptiometry). You may discuss this with your doctor.

The HRT does not increase your risk of breast cancer because it will be replacing the hormones normally produced by the ovaries. Your consultant will discuss with you the treatment length, HRT and additional precautions needed if GnRH analogues needed longer than 6 months. However HRT is contraindicated if you have a history of breast cancer so please make sure that you speak to your clinician about it.

What happens when the medication is stopped?

The ‘menopause’ caused by the GnRH analogue is temporary and reversible. Once the medication is stopped, periods normally restart after 6-10 weeks and there are no long-term effects on a patient’s fertility. Unfortunately, without any further definitive treatment, any problematic symptoms that stopped while taking a GnRH analogue will likely slowly return once treatment is stopped, although the timescale and extent of symptom recurrence is difficult to predict.

Common Gynaecological Conditions GnRH Analogues are used for: Endometriosis/Adenomyosis

A chronic condition where cells from the lining of the uterus (endometrium) can develop in other areas of the body. This condition is hormone sensitive, so temporarily “switching off” hormone production from the ovary can help to identify the condition, and offer a period of relief prior to a more definitive treatment e.g. removal of ovaries (often done with a hysterectomy). If the symptoms don`t improve when the ovaries are “switched off” then removal of the ovaries is unlikely to help.

Premenstrual Syndrome

A condition associated with a person’s menstrual cycle where they will experience a combination of psychological and physical symptoms, which severely affect their quality of life. A 3 month trial with GnRH analogues is occasionally used to investigate the condition; if the symptoms improve when the patient’s ovaries are temporarily “switched off”, this could support the decision for further treatment. If symptoms do not improve, further treatment to remove the ovaries would not be offered.

Fibroids

These are benign swellings which develop from the muscular layer of the uterus and can cause heavy and painful periods. These muscular swellings are hormone sensitive and treatment with a GnRH analogue can temporarily help to shrink the swellings down which can improve symptoms for a time and may help with planned surgery to remove them.

Chronic Pelvic Pain

A trial with GnRH Analogues can be used as a diagnostic test to help differentiate between gynaecological and non-gynaecological causes of chronic pelvic pain. Again if the symptoms are improved by the temporary “switching off” of the ovaries then this may help guide further treatment options for the pain, such as surgery.

There may be other clinical conditions which your Gynaecologist may choose to treat with GnRH Analogues. If this is the case, then they will discuss this with you individually.

These injections can also be used before having an operation as part of getting ready for surgery and to reduce risks such as heavy bleeding. They can also be used as part of a treatment to avoid surgery in some patients.

Possible side effects?

Within the first month of use, there can be a temporary worsening of symptoms called a ‘flare effect’. However, this tends to resolve after the first month.

Menopausal symptoms are relatively common, especially if hormone replacement is not given, but vary between individuals. Symptoms include hot flushes, headaches, mood swings, night sweats, vaginal dryness, weight changes and reduced libido. If these symptoms start to significantly affect quality of life, HRT can be considered to offer some relief.

Bone thinning or osteoporosis is the most concerning side effect and is why prolonged use is often avoided. If treatment is continued beyond 6 months, HRT is needed for the duration of GnRH analogue therapy.

Blood sugar levels may be altered during treatment with GnRH analogues, which may affect control in diabetic patients and require more frequent monitoring of blood glucose.

Patients who were already peri-menopausal may rarely find that they do not recommence their normal periods following treatment with GnRH analogues.

If you experience any side effects that cause you concern, please contact your

treating consultant.

Recommended sites for further information on endometriosis, premenstrual syndrome and chronic pelvic pain:

Royal College of Obstetricians and Gynaecologists: www.rcog.org.uk › patients › patient-leaflets Endometriosis UK: www.endometriosis-uk.org

Contact Us

If you have any queries relating to the GnRH Analogue treatment then please contact your consultant’s secretary, their number can be found on your appointment/correspondence letters.

If your symptoms or condition worsens, or if you are concerned about anything, please call your GP, 111, or 999.

Patient Experience

We know that being admitted to hospital can be a difficult and unsettling time for you and your loved ones. If you have any questions or concerns, please do speak with a member of staff on the ward or in the relevant department who will do their best to answer your questions and reassure you.

Feedback

Feedback is really important and useful to us – it can tell us where we are working well and where improvements can be made. There are lots of ways you can share your experience with us including completing our Friends and Family Test – cards are available and can be posted on all wards, departments and clinics at our hospitals. We value your comments and feedback and thank you for taking the time to share this with us.

Patient Advice and Liaison Service (PALS)

If you have any concerns or questions about your care, we advise you to talk with the nurse in charge or the department manager in the first instance as they are best placed to answer any questions or resolve concerns quickly. If the relevant member of staff is unable to help resolve your concern, you can contact the PALS Team. We offer informal help, advice or support about any aspect of hospital services & experiences.

Our PALS team will liaise with the various departments in our hospitals on your behalf, if you feel unable to do so, to resolve your problems and where appropriate refer to outside help.

If you are still unhappy you can contact the Complaints Department, who can investigate your concerns. You can make a complaint orally, electronically or in writing and we can advise and guide you through the complaints procedure.

How to contact PALS:

Telephone Patient Services: 0300 123 1732 or via email at: wah-tr.PALS@nhs.net

Opening times:

The PALS telephone lines are open Monday to Friday from 8.30am to 4.00pm. Please be aware that you may need to leave a voicemail message, but we aim to return your call within one working day.

If you are unable to understand this leaflet, please communicate with a member of staff.

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