Estreva (Estradiol 0.1%) Gel

Estreva general information

What is Estreva used for?

Hormone replacement therapy (HRT) is a familiar term when talking about the changes women go through at menopause, caused by a lack of the hormone estrogen.  Although a natural part of life, menopause can cause severe problems for some women.  Various different types of HRT are available, and Estreva 0.1% gel is a topical form of HRT that is absorbed through the skin instead of being taken as a tablet. 

You should only use Estreva gel if you have had a hysterectomy or are also taking progesterone as well, because of the health risk of estrogen-only HRT.

Estrogen is the female hormone produced by the ovaries that transforms the girl into the woman and plays a central role in all stages of female reproduction, along with other female hormones like progesterone.  Estrogen stimulates the development of female sexual characteristics, including breast development and body shape.  It regulates the menstrual cycle, triggers ovulation, and stimulates the thickening of the endometrium (lining of the uterus) and thickening of vaginal tissue and its secretions.  It also plays other essential roles including regulating lipid metabolism, and it supports bone density throughout the fertile years of a woman’s life.  As menopause approaches, estrogen production starts to slow down and eventually, no more is produced by the ovaries.  Menstruation ceases and this lack of estrogen brings with it a host of menopausal symptoms, some mild and some quite severe. 

Symptoms of menopause

Symptoms associated with low estrogen in menopause include hot flashes caused by sudden dilation of surface blood vessels.  When this happens at night, they cause night sweats.  Vaginal thinning and dryness known as atrophic vaginitis can cause discomfort or pain with sex and recurrent urine infections.  Other signs of menopause are headaches, mood swings, lack of concentration and loss of energy. 

Loss of bone density is a serious problem related to loss of estrogen and can lead to osteoporosis, which makes the bones brittle so that they fracture more easily.  Estreva gel relieves symptoms of menopause and also helps prevent postmenopausal bone loss (osteoporosis) to reduce the risk of fracture. 

Transgender hormone therapy

Estrogen is an essential component in transgender hormone therapy for male to female transsexuals as part of a gender reassignment program.  Estreva gel helps stimulate the development of female sexual characteristics, to promote the feminisation process, such as breast development.  It also induces metabolic changes such as fat distribution to redefine the general body shape.

How does Estreva work?

Estreva 0.1% is a transdermal gel that contains a synthetic form of estradiol that is chemically and biologically identical to naturally produced estradiol, which is the major and most active form of the female hormone estrogen. 

Estradiol in Estreva gel diffuses out of the gel and is absorbed through the skin into the blood.  It works by passing through the cell membrane and binding to specific receptors inside the cells of its target tissues.  These include the ovaries, uterus, bone and breast tissue.  Estrogen attached to its receptor then interacts directly with the DNA and promotes the expression (activation) of specific genes to make proteins needed for estrogen-dependent processes in those tissues, such as breast cell growth, improved lubrication of vaginal cells and increased bone density. 

Because estradiol in Estreva gel does not pass through the gastrointestinal system but instead enters the blood directly and continuously, it is not metabolised (broken down) by the liver, as happens when estrogen is taken orally in tablet form. 

What does Estreva contain?

Estreva gel contains the active ingredient estradiol hemihydrate 0.1%, which is used for hormone replacement therapy (HRT) to relieve symptoms of estrogen deficiency in menopausal women. 

Each 50 g bottle of gel comes with a dosing pump that delivers a total of 100 doses of 0.5g gel containing 0.5mg estradiol per dose.

What are the side effects of Estreva?

Most medications have some side effects, but they are not experienced by everyone.  Some side effects are commonly experienced when taking Estreva, but others are not so common, and you should discuss any problems or concerns with your primary care physician. 

Common side effects when taking Estreva include irritation where the gel is applied, breast tenderness, breast pain, abdominal pain, nausea, oedema, and headache, breakthrough bleeding and spotting.

What are the health risks of Estreva?

Long-term use of estrogen-only HRT medication like Estreva gel does have risks attached, and it is, therefore, important to consider the risks versus the benefits.  There is an increased risk of breast cancer and endometrial cancer; also stroke and blood clot formation, that can result in deep vein thrombosis.

When should Estreva not be used?

Have a talk with your primary healthcare physician before taking Estreva so that you have a full understanding of what this medicine is for and how to use it.  There are some reasons for not taking a medication; these are called contraindications, and for Estreva you should consider the following before taking Estreva:

• Have you ever had an unusual reaction or an allergy when taking Estreva?
• Are you pregnant or breastfeeding?
• Do you have any problems with your liver or had a liver disease?
• Have you had an estrogen-dependent cancer including cancer of the breast or endometrium?
• Have you had any condition caused by a blood clot such as deep vein thrombosis (blood clots in the leg), pulmonary embolism (blood clot in the lungs)?
• Do you have a heart condition like angina and have you ever had cardiovascular disease, including a heart attack or stroke or uncontrolled high blood pressure?
• Have you had abnormal genital bleeding of unknown cause?

What medications interact with Estreva?

Some medicines interact with Estreva and may affect the way it works, or are affected by Estreva or increase side effects; you should discuss possible interactions with your primary care physician.  These may include medications that increase the metabolism of estrogen, such as anticonvulsants like phenytoin and carbamazepin, anti-infectives like rifampicin, rifabutin, nevirapine, efavirenz or preparations containing St John's Wort. 

If other medications may interact with Estreva, your doctor will discuss these with you. 

How should Estreva be used and for how long?

Estreva gel 0.1% comes with a dosing pump and each dose delivers 0.5g of gel containing 0.5 mg of estradiol. 

You should apply Estreva gel three times daily for either 24 or 28 days per month.  The dose you take may be adjusted by your doctor, and you should use your Estreva gel for as long as your doctor recommends.

You should apply Estreva gel by rubbing into clean, dry, unbroken skin on your abdomen, thighs, arms and shoulders but not the breasts or face.  Use a different sites for each application.  Do not apply to skin that is red or irritated and avoid contact with your eyes.  Allow the gel to dry on your skin for a few minutes and do not wash the skin or apply other skincare products until at least one hour after application.  Wash your hands after applying Estreva gel.  

Unless you have had your uterus removed, you will probably be taking a form of progesterone as well as Estreva

Missed dose of Estreva

If you miss a dose of Estreva gel take it as soon as you remember, unless it is time to take the next dose, then skip the missed dose.  Do not take a double dose.

How should Estreva be stored?

You should store your Estreva gel below 25°C in a cool dry place.