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Linaclotide-associated severe diarrhoea affecting desogestrel progestogen-only pill absorption — DFSRH MCQ

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EasyIrritable Bowel SyndromeLinaclotide-associated severe diarrhoea affecting desogestrel progestogen-only pill absorptionDFSRH

A 34-year-old woman with moderate-to-severe constipation-predominant irritable bowel syndrome recently started linaclotide after inadequate response to conventional laxatives. She uses desogestrel 75 micrograms daily, taken consistently at 08:00. Today she took desogestrel at 08:00 and developed severe watery diarrhoea at 09:00, followed by several further episodes. The diarrhoea resolved by 21:00, and she seeks contraceptive advice at 22:30. She has not taken a replacement pill. All preceding pills were taken correctly. She had condomless intercourse 2 days ago but has had no intercourse since the diarrhoea began. Which is the most appropriate contraceptive advice?

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

Reveal the answer and explanation

Correct answer: E — Take one desogestrel pill now and the next at the usual time; use condoms for 48 hours and do not offer emergency contraception

Explanation lettering: C = shown as A · A = shown as B · D = shown as C · B = shown as D

Severe watery diarrhoea soon after a progestogen-only pill may prevent adequate absorption, so the 08:00 desogestrel tablet cannot be relied upon. A replacement tablet should be taken as soon as possible. Because she presents 14.5 hours after the original tablet was due, the replacement is outside the 12-hour window for a desogestrel POP; missed-pill guidance therefore applies. She should take a tablet now, take the next tablet at the usual time, and use condoms or abstain until correct pill-taking has continued for 48 hours. Emergency contraception is not indicated. With correctly used desogestrel POP before the missed dose, intercourse occurring before that dose is not considered to confer pregnancy risk; she has had no intercourse during the interval of potentially reduced protection. A is incorrect because the potentially unabsorbed pill requires replacement. B incorrectly treats intercourse before the missed desogestrel pill as an indication for emergency contraception. C applies a 7-day precaution interval, which is used for missed drospirenone POP rather than desogestrel POP. D correctly advises replacement but overlooks that it is being taken more than 12 hours late. Linaclotide is not a hepatic enzyme inducer; the contraceptive concern arises from severe diarrhoea impairing intestinal absorption, not from a metabolic drug interaction.

Reference: FSRH Guideline: Progestogen-only Pills (August 2022, amended July 2023) — https://www.fsrh.org/Common/Uploaded%20files/documents/fsrh-ceu-clinical-guideline-progestogen-only-pills-aug22-amended-11july-2023-.pdf Constella 290 micrograms hard capsules — Summary of Product Characteristics (19 June 2026) — https://www.medicines.org.uk/emc/product/2041/smpc