Doxycycline vs Levonorgestrel: side-by-side comparison
Doxycycline (Tetracycline antibiotic) and Levonorgestrel (Synthetic progestin (emergency contraception)) 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 | Doxycycline | Levonorgestrel |
|---|---|---|
| Therapeutic class | Tetracycline antibiotic | Synthetic progestin (emergency contraception) |
| CAS | 564-25-0 | 797-63-7 |
| ATC | J01AA02 | G03AC03 |
| Molecular weight | 444.43 g/mol | 312.5 g/mol |
| Brands with this active ingredient | 1 | 1 |
What they share
Doxycycline and Levonorgestrel 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
Doxycycline acts by a different mechanism than Levonorgestrel, 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
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. 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.
Indications compared
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… 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…
Safety profile
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. Levonorgestrel: Les effets indésirables fréquents de la contraception d'urgence comprennent nausées, céphalées, fatigue, vertiges, tension mammaire et modifications du cycle menstruel.
Questions fréquentes
Is Doxycycline better than Levonorgestrel? ▾
Doxycycline and Levonorgestrel are not "better or worse" — they treat different things. The sensible question is which fits your specific need.
Can Doxycycline and Levonorgestrel 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 Doxycycline
Products with Levonorgestrel
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