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Introduction
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Implanon is a single, flexible sub-dermal implant 4cm x 2mm which contains 68mg of a synthetic progestagen, etonorgestrel. It is designed to be inserted under local anaesthetic directly under the skin of the inner aspect of the non-dominant upper arm
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The implant releases approximately 40 micrograms of etonorgestrel /day which:
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- inhibits ovulation by suppressing the LH surge
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- increases viscosity of cervical mucus, reducing sperm penetration and motility
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- provides effective contraception for 3 years
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After removal etonorgestrel levels fall rapidly and are undetectable after a week and the majority of women will ovulate in the first month.
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It is a highly effective, convenient contraceptive method with a Pearl Index of <0.07 per 100 woman years, provided it is inserted correctly at the correct time of the menstrual cycle.
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It is a recommendation of the TGA, RANZCOG and medical defence organizations that doctors prescribing Implanon have attended a training session in patient selection and counselling and Implanon insertion and removal techniques arranged by the manufacturer Organon. Wherever possible, it is also recommended that an experienced practitioner supervise the first insertion. A correctly inserted Implanon is easily palpable. Removal of Implanon after correct insertion is a simple procedure under local anaesthetic
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[Inquiries re training sessions to Organon - Tel: 1800 644546, clinical supervision at the Royal Women's Hospital available through arrangement with Choices Clinic Nurse Coordinator, Tel: 03 8345 3138.]
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Advantages of method
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- low cost PBS availability $23.10 - $3.70 with concession (2003)
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- suitable for women with a contraindication to oestrogen
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Contraindications
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Absolute:
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- undiagnosed vaginal bleeding
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- active thromboembolic disease
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- present or history of severe liver disease (abnormal LFT's)
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- progestagen dependent tumors
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- hypersensitivity to components of Implanon
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Relative:
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- long term use of liver enzyme inducing drugs can reduce efficacy
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- PH/FH thromboembolic disease - clinical trial data shows no adverse effects of Implanon on clotting parameters, likely that like other progestagen only methods i.e risk of VTE is minimal (esp. c.f. to OC pill) but data on VTE events limited
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- efficacy in women over 100kg could be less - such women were excluded from clinical trials and etonorgestrel levels are inversely related to body weight
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- women for whom regular periods are important
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Use in breast feeding has not been demonstrated to have adverse effects on infants to 6 months of age.
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Side effects
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Disturbance of menstrual pattern is usual, so the method will only be acceptable to women who can tolerate this.
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- bleeding approximating normal 35%;
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- frequent and or prolonged bleeding 18%.
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Menstrual disturbance is the commonest reason for removal requests. There is no proven method of treatment. NSAID'S e.g. mefanemic acid or oestrogen supplementation could be tried based on varying anecdotal results only.
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A research study of treatment for Implanon induced bleeding problems is being conducted at the Royal Women's Hospital. Inquiries to Choices Clinic (phone the Women's: 03 8345 2000).
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NB: Implanon is not recommended to control preexisting menstrual bleeding problems.
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Other: (5-10%)
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- breast tenderness, fluid retention
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- skin disorders (note pre-existing acne may improve with Implanon)
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Insertion
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Women wishing to have Implanon inserted can be referred to the Choices Clinic if their General Practitioner has not attended training course. Correct insertion technique and timing is essential as most failures since introduction to Australia have been due to the woman already being pregnant at the time of insertion or non-insertion (faulty insertion technique and position not checked post insertion)
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Implanon is effective immediately if inserted during day 1-5 of the patient's menstrual cycle. At any other time in the cycle it is important to be certain the patient could not be pregnant and alternative contraception should be used for seven days after insertion.
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It can be inserted with immediate effectiveness in women:
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- on COC (pref. pill free interval to minimize bleeding irregularities)
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- on Depo Provera before next injection due;
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- after termination of pregnancy.
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NB: in IUD users if insertion of Implanon not done day 1-5 of cycle IUD should be left in situ for 7 days post insertion as a preovulatory follicle may be present
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Insertion technique - see manufacturers instructions / training course
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NB: Implanon is not recommended to control pre-existing menstrual bleeding problems
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Post insertion dressing and pressure bandage to minimize bruising for 48 hours and Review 3 months
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Removal
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Women requesting removal of Implanon rod should be referred to their General Practitioner or to Choices Clinic (call Outpatient Clinic Appointments - 8345 3032 or Clinic Nurse Coordinator - 8345 3138). Implanon should generally not be removed in the Emergency Department, unless the attending doctor has attended a training course and the Implanon is easily palpable and alternative contraception can be provided if required.
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No clinician should incise the skin with a view to removing Implanon unless they can feel the rod clearly and they are sufficiently confident of their technique to be certain that they can remove it. Removal of a correctly inserted Implanon should be a simple procedure performed through a 2-3 mm incision under local anaesthetic
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Removal technique - see manufacturers instructions / training course.
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Management of women in whom Implanon is not palpable
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If Implanon is not palpable either:
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- it is not present (i.e. insertion failure)
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or
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- it has been inserted too deeply
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The woman should be advised to use alternative contraception until the situation is clarified.
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Implanon is usually identifiable by ultrasound examination by a sonographer with experience of the ultrasound appearance of Implanon - available through Royal Women's ultrasound service.
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Further management if removal required can be most efficiently arranged through Choices Clinic Nurse Coordinator. If Implanon is visible on ultrasound, removal can be arranged through the clinic either under local anaesthetic or under general anaesthetic by hospital general surgeon if required.
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If Implanon cannot be visualised on ultrasound, depending on the clinical situation:
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- presumptive evidence of non insertion can be based on progesterone levels consistent with ovulation;
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- serum level of etonorgestrel can be estimated (requires blood to be sent to Germany by Organon);
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- further imaging of arm by MRI will be arranged through Choices clinic.
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NB Implanon is not visible on Xray or CTscan
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Royal Women's Hospital Clinical Practice Guidelines (CPGs) are intended to provide guidance to health care professionals, based on a thorough evaluation of research evidence, on the practical assessment and management of specific clinical issues or situations. The guidelines allow some flexibility on the part of the health care professional based on the needs of the specific patient for whom they are caring.
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