Drug interactions
Levonorgestrel + Nelfinavir
Severity: Moderate
Levonorgestrel and Nelfinavir: moderate interaction.
Last updated
For healthcare professionals — reference only. This page is a brief summary, not medical advice and not a substitute for official labeling or clinical judgement. Always verify before prescribing or dispensing.
Summary
Nelfinavir may alter hormonal contraceptive exposure, which can affect contraceptive reliability or increase progestogenic adverse effects. Clinical significance for a levonorgestrel intrauterine system, which has mainly local action, is limited.
What this interaction means in plain words
Levonorgestrel and Nelfinavir can affect each other. The combination is often manageable, but it may need a change of dose, a change of timing, or extra checks while both are taken.
Levonorgestrel belongs to Endocrine; Nelfinavir belongs to Anti Virals.
Why it happens
Nelfinavir inhibits CYP3A4 but also has some inducing effects on hormone metabolism, producing variable exposure changes.
What to do
Monitor for progestogenic adverse effects and bleeding pattern changes; for oral products consider an additional barrier method.
What to ask your pharmacist
- Should I take them at different times of day?
- Does the dose of either medicine need to change?
- Is there anything I should avoid, such as alcohol or certain foods, while on both?
Pro+ members
Unlock the full page
Create an account and start a Pro+ trial to unlock the full management advice for Levonorgestrel and Nelfinavir, the additional notes, the evidence detail and the whole-prescription interaction checker.
- Full clinical management advice
- Additional notes
- Evidence detail
- Interaction checker for a whole prescription
Try Pro+ free for 7 days on the web. No card needed.
Other interactions of Levonorgestrel
Other interactions of Nelfinavir
- Alfuzosin + Nelfinavir Contraindicated
- Avanafil + Nelfinavir Contraindicated
- Dronedarone + Nelfinavir Contraindicated
- Eletriptan + Nelfinavir Contraindicated
- Ergotamine + Nelfinavir Contraindicated
- Flibanserin + Nelfinavir Contraindicated
Frequently asked questions
Can I take Levonorgestrel with Nelfinavir?
MediHelp rates the interaction as moderate. Levonorgestrel and Nelfinavir can affect each other. The combination is often manageable, but it may need a change of dose, a change of timing, or extra checks while both are taken. Nelfinavir may alter hormonal contraceptive exposure, which can affect contraceptive reliability or increase progestogenic adverse effects. Clinical significance for a levonorgestrel intrauterine system, which has mainly local action, is limited.
How serious is the interaction between Levonorgestrel and Nelfinavir?
MediHelp rates it moderate, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Monitor for progestogenic adverse effects and bleeding pattern changes; for oral products consider an additional barrier method.
What other medicines interact with Levonorgestrel?
MediHelp also lists interactions of Levonorgestrel with, for example, Amobarbital, Apalutamide, Belzutifan. The full list is on the Levonorgestrel page.
Full monographs, dosing and an interaction checker in the MediHelp app
Open the complete reference, check multi-drug interactions and use dosing tools in the MediHelp app.
