etonogestrel: clinical use

Prescribing considerations

• Exclude pregnancy and review medical, family and medication history before insertion.
• Assess thrombotic and arterial vascular risk factors, liver disease, breast pathology, unexplained bleeding, blood pressure and relevant mental-health history.
• Counsel that bleeding patterns are unpredictable and are a common reason for discontinuation.
• Insertion and removal must be undertaken aseptically by a clinician trained in the techniques; confirm palpability immediately afterwards.
• Localise a non-palpable implant using appropriate imaging rather than exploratory surgery. Consider chest imaging if it cannot be found in the arm.
• Review suitability during prolonged immobilisation, significant hypertension, new liver dysfunction, thrombosis or serious mood symptoms.

Contraindications and cautions

• Active venous thromboembolic disorder
• Known or suspected sex-steroid-sensitive malignancy
• Current or previous benign or malignant liver tumour
• Severe hepatic disease while liver function remains abnormal
• Undiagnosed vaginal bleeding
• Hypersensitivity to etonogestrel or an excipient

Monitoring

• Record blood pressure and perform a clinically directed examination before insertion.
• Confirm the implant is palpable after insertion and at relevant reviews; investigate promptly if it cannot be felt.
• Review bleeding changes when clinically indicated and exclude pregnancy or gynaecological pathology where appropriate.
• Monitor blood pressure, adverse effects, insertion-site problems and new interacting medicines.
• Monitor people with diabetes carefully for changes in glucose control after initiation.

Clinical pharmacology

Etonogestrel is the active metabolite of desogestrel and a high-affinity progesterone-receptor agonist. It primarily inhibits ovulation and also affects cervical mucus. It is highly protein bound, metabolised by reduction and hydroxylation, and its metabolites are excreted in urine and faeces.

Formulation and product differences

• The selected product is a single radiopaque, non-biodegradable ethylene-vinyl-acetate implant containing barium sulphate.
• It is supplied preloaded in a sterile, disposable applicator designed for subdermal insertion.
• Radiopacity supports localisation by imaging when the implant cannot be palpated.

Implant

Route: Implant

Strengths: 68 mg