Levonorgestrel vs Cetirizine: side-by-side comparison
Levonorgestrel (Synthetic progestin (emergency contraception)) and Cetirizine (Second-generation H1 antihistamine) 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 | Cetirizine |
|---|---|---|
| Therapeutic class | Synthetic progestin (emergency contraception) | Second-generation H1 antihistamine |
| CAS | 797-63-7 | 83881-51-0 |
| ATC | G03AC03 | R06AE07 |
| Molecular weight | 312.5 g/mol | 388.89 g/mol |
| Brands with this active ingredient | 1 | 1 |
What they share
Levonorgestrel and Cetirizine 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 Cetirizine, 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. Cetirizine: La cétirizine bloque sélectivement les récepteurs H1 périphériques de l'histamine, antagonisant les effets de l'histamine libérée par les mastocytes lors des réactions allergiques.
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… Cetirizine: La cétirizine est autorisée chez l'adulte et l'enfant dans le traitement de la rhinite allergique, saisonnière comme perannuelle, de la conjonctivite allergique et de l'urticaire chronique idiopathique.
Safety profile
Levonorgestrel: Les effets indésirables fréquents de la contraception d'urgence comprennent nausées, céphalées, fatigue, vertiges, tension mammaire et modifications du cycle menstruel. Cetirizine: La cétirizine est généralement bien tolérée.
Questions fréquentes
Is Levonorgestrel better than Cetirizine? ▾
Levonorgestrel and Cetirizine are not "better or worse" — they treat different things. The sensible question is which fits your specific need.
Can Levonorgestrel and Cetirizine 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 Cetirizine
Les informations publiées sur ce site sont fournies à titre documentaire et pédagogique. Elles ne remplacent pas l'avis d'un professionnel de santé qualifié.