A 32-year-old woman with BMI 32 requests a subdermal progestogen implant (etonogestrel, Nexplanon). She takes enzyme-inducing medication (rifampicin). Which statement about efficacy and management is correct per UKMEC 2016 guidance?
- A UKMEC 2 — implant can be used; no additional contraception needed as rifampicin does not affect implant levels
- B UKMEC 3 — risks generally outweigh benefits; a barrier method or copper IUD should be offered instead
- C UKMEC 2 — implant can be used with additional barrier contraception and earlier replacement at 2 years instead of 3 ✓
- D UKMEC 1 — no restriction; implant is unaffected by hepatic enzyme inducers
Explanation
UK MEC (UKMEC 2016) classifies enzyme-inducing drugs (including rifampicin) with etonogestrel implant as UKMEC 2 (benefits outweigh risks, method can generally be used), not UKMEC 3. However, the practical advice is that enzyme inducers significantly lower etonogestrel plasma levels, reducing contraceptive efficacy. FSRH guidance recommends additional barrier contraception during rifampicin use and for 28 days afterwards, and consideration of earlier replacement (some guidelines suggest replacing at 2 years rather than 3 years). UKMEC 3 would mean risks generally outweigh benefits — this is not the correct category for this combination.
Reference: Shaw's Textbook of Gynaecology, 17th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.