Emergency Contraception at 68 Hours in a Patient With a BMI of 34 and Epilepsy
Ms. R., 26, arrives at your pharmacy at 19:00 on a Sunday, 68 hours after unprotected intercourse, and asks for 'the morning-after pill.' She is 1.68 m tall and weighs 96 kg (BMI 34). Her medications are lamotrigine 150 mg BID for epilepsy and sertraline 50 mg daily. She has no migraine with aura, no history of venous thromboembolism, blood pressure 118/74 mmHg, and no allergies. Her last menstrual period began 16 days ago and was normal. She uses no regular contraception and is not breastfeeding. She has heard of the copper IUD but says, 'I'd rather just take a pill - can't I do that?' She is willing to have a pregnancy test today, which is negative. She asks how effective each option is and whether the pill will interact with her seizure medication.
1. Compare the emergency contraception options for this patient and recommend one, with rationale.
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| Option | Timing | Efficacy notes | Fit for this patient |
|---|---|---|---|
| Levonorgestrel 1.5 mg | ≤72 h (better the sooner) | Declines with delay; reduced at BMI >30 or weight >70 kg | Within the window at 68 h, but the least favourable efficacy profile |
| Ulipristal acetate 30 mg | ≤120 h | More effective than levonorgestrel, especially at 72–120 h; some decline at higher BMI but still preferred over levonorgestrel | Good option if an IUD is not feasible |
| Copper IUD | ≤5 days (120 h) | Most effective (>99%); BMI-independent; also long-term contraception | Best option, if same-day insertion is available |
Recommendation: offer the copper IUD first and arrange same-day insertion through a clinic or gynecologist. If that is not possible today, provide ulipristal 30 mg now rather than levonorgestrel, because she is 68 hours out and has a BMI of 34. Levonorgestrel is the fallback only if ulipristal is unavailable.
Counsel: none of these are abortifacients; they work mainly by delaying ovulation. Ulipristal may be less effective if ovulation has already occurred, so she needs a pregnancy test in 3 weeks. If she chooses the IUD, it can stay for up to 10 years and is the most reliable option.
2. Address the lamotrigine interaction and seizure risk, and explain how you would counsel her.
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Lamotrigine: a single dose of levonorgestrel or ulipristal is not expected to meaningfully alter lamotrigine concentrations - lamotrigine is not a strong enzyme inducer, and neither emergency contraceptive is a major inhibitor of its glucuronidation. So the emergency contraception itself does not compromise seizure control.
The real interaction is with ongoing hormonal contraception. Estrogen-containing contraceptives induce lamotrigine glucuronidation and can lower lamotrigine levels by about 50%, increasing seizure risk; stopping them can raise levels and cause toxicity (diplopia, ataxia, rash). If she starts a combined pill, patch or ring, her neurologist should be involved and the lamotrigine dose may need to increase. A copper IUD or levonorgestrel IUD avoids this interaction entirely - another reason to favour the IUD here.
Counsel: do not stop lamotrigine; report any increase in seizure frequency, rash, or new neurological symptoms; use condoms until a regular method is established.
3. What follow-up and additional care do you provide after she leaves the pharmacy?
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Follow-up:
- Pregnancy test in 3 weeks if menses is late or abnormal; a negative test today does not exclude conception from this exposure.
- STI screening: offer chlamydia/gonorrhea nucleic acid testing, HIV and syphilis serology, and discuss window periods and treatment.
- Contraception plan: if she chose ulipristal, wait 5 days before starting a hormonal method; use condoms in the interim. If she chose the IUD, confirm insertion and check strings.
- Adherence and safety: document the consultation, the option chosen and the rationale; provide written information.
- Scope of practice: in provinces where pharmacists can prescribe emergency contraception, prescribe; otherwise refer urgently to a clinic that can see her today, given the 120-hour window.
- If she develops abdominal pain or heavy bleeding: assess for ectopic pregnancy.