Levonorgestrel vs Doxycycline: side-by-side comparison
Levonorgestrel (Synthetic progestin (emergency contraception)) and Doxycycline (Tetracycline antibiotic) belong to different therapeutic classes and are rarely substitutes for each other. The comparison is useful when a single patient is weighing both options for adjacent or overlapping needs.
| Property | Levonorgestrel | Doxycycline |
|---|---|---|
| Therapeutic class | Synthetic progestin (emergency contraception) | Tetracycline antibiotic |
| CAS | 797-63-7 | 564-25-0 |
| ATC | G03AC03 | J01AA02 |
| Molecular weight | 312.5 g/mol | 444.43 g/mol |
| Brands with this active ingredient | 1 | 1 |
What they share
Levonorgestrel and Doxycycline share the common regulatory framework for prescription active ingredients, bioequivalence standards for generics, and pharmacist oversight. Beyond that, points in common are limited.
Key differences
Levonorgestrel acts by a different mechanism than Doxycycline, with indications that barely overlap. Comparing the two is useful when a clinician has mentioned both in the same context or the patient wants to understand why one was prescribed instead of the other.
Mechanisms compared
Levonorgestrel: En contraception d'urgence, le lévonorgestrel agit principalement en retardant ou en inhibant l'ovulation lorsqu'il est pris avant le pic de LH. Doxycycline: La doxycycline se lie de façon réversible à la sous-unité ribosomique 30S des bactéries sensibles, inhibant la synthèse protéique en empêchant la fixation de l'aminoacyl-ARNt sur le site A du ribosome.
Indications compared
Levonorgestrel: Le lévonorgestrel est autorisé en contraception d'urgence (dose unique de 1,5 mg), en contraception orale régulière (associé à l'éthinylestradiol ou en progestatif seul), et comme principe actif des dispositifs intra-uté… Doxycycline: La doxycycline est autorisée chez l'adulte et l'adolescent dans le traitement de l'acné, de la rosacée, des infections des voies respiratoires, des pneumonies atypiques, des infections sexuellement transmissibles dont le…
Safety profile
Levonorgestrel: Les effets indésirables fréquents de la contraception d'urgence comprennent nausées, céphalées, fatigue, vertiges, tension mammaire et modifications du cycle menstruel. Doxycycline: Les effets indésirables fréquents comprennent troubles digestifs, photosensibilité, irritation œsophagienne en l'absence de prise avec une quantité d'eau suffisante et en position debout, et candidose vaginale.
Questions fréquentes
Is Levonorgestrel better than Doxycycline? ▾
Levonorgestrel and Doxycycline are not "better or worse" — they treat different things. The sensible question is which fits your specific need.
Can Levonorgestrel and Doxycycline be combined? ▾
Whether they can be combined depends on the indications and the interaction profile of each. If both are in a single prescription, the prescriber has weighed it; in self-medication they should never be combined.
Do they have the same side-effect profile? ▾
No — they belong to different classes and have distinct side-effect profiles. Each has its own prescribing information.
Products with Levonorgestrel
Products with Doxycycline
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