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Progestogen-only contraceptive implant

Etonogestrel

Brand names: Nexplanon, Implanon NXT

A progestogen used for long-acting reversible contraception, available as a subdermal implant and as the active progestogen in some combined hormonal and vaginal ring products.

Dosing — being independently re-sourced

ClinCalc Pro is rebuilding its dose data from primary open sources — the manufacturer SmPC (eMC), the WHO Model Formulary and other official references — under clinician review. This drug's structured dose is not yet published here. Confirm all doses against the product SmPC and your local formulary before prescribing.

Clinical monograph

How it works

It inhibits ovulation, thickens cervical mucus and alters the endometrium, preventing fertilisation and implantation.

Prescribing in practice

  • Contraindicated in active venous thromboembolism and in current or past breast cancer; exclude pregnancy before insertion.
  • The implant must be correctly inserted and located subdermally; impalpable or deep implants require imaging and specialist removal.
  • Irregular or unpredictable bleeding is common and is a frequent reason for discontinuation; counsel beforehand.

Monitoring

Check the implant is palpable after insertion and review bleeding pattern, blood pressure and contraceptive needs periodically.

Counselling the patient

  • Bleeding patterns often change and may be irregular, especially at first.
  • The implant provides long-acting contraception but does not protect against sexually transmitted infections.
  • Note the insertion date and when replacement or removal is due.

Evidence & guidelines

Long-acting reversible contraception including the progestogen implant is recommended as highly effective by NICE.

Reference: FSRH CEU guidance; NICE CKS; Drug verified in RxNorm (NLM); confirm dosing against the manufacturer SPC (eMC). Verify against your local formulary and current prescribing references before prescribing. Monograph status: clinician-reviewed (2026-07-04).

Related

Curated clinical cross-links plus same-class fallbacks.

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