Synthetic progestin (emergency contraception)
Levonorgestrel and grapefruit: a real interaction?
Grapefruit is famous as the juice that interacts with medications, and the warning is real for a number of drugs. Whether it matters specifically for Levonorgestrel (Levonorgestrel) at 1.5mg depends on whether the active ingredient Levonorgestrel is metabolised by CYP3A4 in the gut wall and how much that pathway contributes to first-pass metabolism.
The CYP3A4 mechanism
Grapefruit (and its juice) inhibits CYP3A4 enzymes in the gut wall, increasing the absorbed dose of medications metabolised by that enzyme. For drugs in the Synthetic progestin (emergency contraception) class that go through CYP3A4 first-pass metabolism, regular grapefruit consumption can raise plasma levels of Levonorgestrel by a clinically meaningful margin and amplify side effects.
What to do with Levonorgestrel
According to the prescribing information for Levonorgestrel, if grapefruit is flagged as an interaction, the safest practice is to avoid grapefruit entirely or to discuss timing with the prescriber. In emergency contraception, levonorgestrel works primarily by delaying or inhibiting ovulation when taken before the LH surge. A small occasional serving may be tolerable; daily large servings around the time of Levonorgestrel dosing are not recommended at 1.5mg.
Frequently asked questions
Can I eat grapefruit while on Levonorgestrel? ▾
For some Synthetic progestin (emergency contraception) medications, grapefruit is best avoided or limited because of CYP3A4 inhibition. Whether Levonorgestrel specifically is affected depends on Levonorgestrel; the prescribing information lists this. When in doubt, ask the pharmacist or check the patient leaflet.
How much grapefruit is too much with Levonorgestrel? ▾
For drugs where the interaction matters, even modest daily grapefruit intake (one whole grapefruit or one large glass of juice) can shift drug levels noticeably. For Levonorgestrel at 1.5mg, individual tolerance varies; the cautious choice is to avoid grapefruit if any interaction is mentioned.
Products containing Levonorgestrel
More on Levonorgestrel
- With alcoholLevonorgestrel and alcohol — is it safe to drink?
- With foodShould Levonorgestrel be taken with food?
- Side effectsLevonorgestrel side effects: common, rare and warning signs
- Dosage guideLevonorgestrel dosage guide: how much to take and when
- OnsetHow fast does Levonorgestrel start working?
- DurationHow long does Levonorgestrel last?
The information on this website is provided for reference and educational purposes only. It does not replace consultation with a qualified healthcare professional.