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Lamotrigine and CHC — DFSRH MCQ

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HardPharmacologyLamotrigine and CHCDFSRH

A patient with epilepsy is stable on lamotrigine monotherapy and requests a combined vaginal ring. Maintaining seizure control is her priority. What is the best response?

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Correct answer: D — Choose non-CHC contraception or coordinate with the epilepsy team

The best answer is “Choose non-CHC contraception or coordinate with the epilepsy team”. Ethinylestradiol-containing CHC can substantially lower lamotrigine concentrations, risking loss of seizure control, while lamotrigine levels may rise during a hormone-free interval and cause adverse effects. The vaginal ring is still CHC and does not avoid this interaction. A non-CHC method avoids those fluctuations; if CHC is strongly preferred, coordinated specialist monitoring and dose planning are needed.

Reference: CoSRH/FSRH, Drug Interactions with Hormonal Contraception (May 2022): https://www.cosrh.org/Common/Uploaded%20files/documents/drug-interactions-with-hormonal-contraception-5may2022.pdf