Hormone Implants
Hormone implants are small crystalline slow release pellets containing 100% body / bio-identical hormones. Both estradiol 50mg and testosterone 100mg implants are unlicensed products.
Implants are usually given every 6 to 8 months, but not more frequently. A blood test is required every 6 to 12 months to monitor your hormone levels with the dose and frequency changed accordingly if necessary. Our guidelines follow safe practice to ensure normal therapeutic blood levels are maintained. The normal estradiol range is 300 to 600pmol but exceptionally a higher limit may be agreed.
Implant procedure
Implants are inserted under the skin, usually in the abdomen (stomach) or in the buttock. With a local anaesthetic, a small 5mm incision (cut) is made in the skin. Using an ‘introducer’ the implant is inserted under the skin into the fatty layer. The wound is covered with ‘steristrips’ and a sterile dressing which should remain in place for 48 hours and the wound kept dry. Occasionally a soluble stitch is used if the wound continues to bleed which will dissolve and falls out in 7 to 10 days, but if not it should be removed by a healthcare practitioner.
You may experience localised bruising, pain and discomfort at the wound site for a few days after the procedure and simple painkillers will help reduce symptoms. You will be left with a small scar from the incision. It is very rare for implant wounds to become infected and antibiotics may be prescribed by your GP if required. Occasionally testosterone implants may be rejected, if this occurs, contact your healthcare practitioner.
Risks and benefits of estradiol implants
Please speak to your clinician for individualised risks and benefits and ensure you are happy to continue this treatment. The risks and benefits of implants are the same as for any transdermal (via the skin) hormone replacement therapy (HRT).
Benefits include improved response when other treatments have failed and long-term bone protection. Risks include thromboembolic risk (blood clots) or stroke but comparable to other transdermal estradiols, when the serum estradiol remains within normal physiological range.
Tachyphylaxis
Estradiol levels will accumulate in the blood over time and studies have found that the estradiol may reach higher than normal levels in about 3% of women resulting in a return of symptoms sooner than six months; this is known as tachyphylaxis. If your estradiol results are high we will adjust your treatment accordingly and your next implant may be deferred.
Blood tests
To reduce the risks of tachyphylaxis a blood test is required two weeks before every implant. If the result is too high your implant may be deferred until it has returned within range. Some menopause symptoms may return before the next implant is due, in which case we advise you to use a ‘top-up’ of estradiol patch or gel which you’re GP can prescribe. You must stop using your ‘top-up’ estradiol or testosterone one week before you have a blood test but may resume again straight afterwards.
Endometrial protection of the womb
If you still have your uterus (womb) you will also be prescribed a progestogen/progesterone. This is to prevent the risk of developing endometrial hyperplasia (thickening of the womb lining) which may lead to endometrial cancer. Without adequate progestogenic opposition the additional risk increased cancer risk is 5 cases per 1000 women after 5 years of use. The gold standard is Mirena levonorgestrel intrauterine device (IUS) is used with implants for maximum protection but other options can be discussed with your clinician.
Discontinuing estradiol implants
Estrogen implants should be considered as a non-reversible HRT as it cannot be removed once inserted. If you are planning a family within 12 months of treatment this option is not suitable for you.
Estrogen implants give a therapeutic effect for 6 to 8 months. However, the residual implant may continue to release small amounts of estradiol for up to 18 to 24 months. Women who still have their uterus (womb) must continue using a progestogen, such as the Mirena IUS, until their serum estradiol blood test is within the postmenopausal range (<70pmol) or, continue with cyclical progesterone until no further bleeding occurs.
Testosterone implants
For women already on HRT, testosterone was licensed as a patch for loss of libido, but was withdrawn for commercial reasons, not safety concerns. Unlicensed testosterone implants deliver a normal female dose but depending upon an individual’s sensitivity, side effects may vary. The most common side effect is hair growth which is generally reversible. Less commonly acne, male pattern hair loss or deepening of the voice may occur.
(Unlicensed drug: a drug that is not licenced for use in the UK but can be used by specialists)