skip to main content

Contraception during tamoxifen treatment for current breast cancer — DFSRH MCQ

Instant feedback + full explanation. One question, done properly.

HardDuloxetineContraception during tamoxifen treatment for current breast cancerDFSRH

A 38-year-old woman attends for contraception following treatment for oestrogen receptor-positive invasive breast cancer diagnosed 7 months ago. She completed breast-conserving surgery and radiotherapy and is receiving adjuvant tamoxifen. She wants highly effective reversible contraception and declines sterilisation. She is on day 5 of a normal menstrual period, has had no intercourse since it began, and has no contraindication to intrauterine contraception. She also takes duloxetine 60 mg daily for chronic neuropathic pain. This predates tamoxifen, and no medication-interaction review is documented. Her pain is well controlled and she has previously developed marked dizziness after missing duloxetine doses. Which management plan is most appropriate?

Educational content. Not a substitute for clinical judgement or local policy.

Reveal the answer and explanation

Correct answer: E — Insert a copper intrauterine device; continue duloxetine pending prompt prescriber and oncology review

The copper intrauterine device is the preferred highly effective reversible method. FSRH recommends highly effective non-hormonal contraception first-line after breast cancer; hormonal methods should generally be avoided, with current breast cancer corresponding to UKMEC 4. Tamoxifen is not contraceptive, and pregnancy should be avoided during treatment. Duloxetine does not induce CYP3A and therefore does not create the usual enzyme-induction concern about contraceptive failure. However, it is a moderate CYP2D6 inhibitor. CYP2D6 contributes to conversion of tamoxifen to endoxifen, and CYP2D6 inhibition can reduce endoxifen exposure. The clearest regulatory recommendation concerns potent inhibitors, so the evidence does not justify unilateral immediate withdrawal of established duloxetine. The potential interaction nevertheless merits prompt review by the relevant prescriber and oncology team, who can assess whether a carefully tapered switch is appropriate. Abrupt discontinuation is specifically discouraged because withdrawal reactions are common. A and B provide progestogen exposure during current breast cancer. C has the same eligibility problem and initiates an unnecessary taper before specialist review. D selects the correct contraceptive method but immediate duloxetine cessation risks clinically significant withdrawal. E therefore integrates contraceptive eligibility, tamoxifen pharmacology and safe sequencing of medication review.

Reference: FSRH CEU Guidance: Supporting Contraceptive Choices for Individuals Who Have or Have Had Breast Cancer (November 2023) — https://www.fsrh.org/Common/Uploaded%20files/documents/fsrh-cadbc-guidance-document-15-nov-2023.pdf Tamoxifen 20mg Tablets — Summary of Product Characteristics (15 May 2026) — https://www.medicines.org.uk/emc/product/12211/smpc Duloxetine Milpharm 30mg gastro-resistant capsules — Summary of Product Characteristics (30 August 2024) — https://www.medicines.org.uk/emc/product/6980/smpc