Diclofenac vs Levonorgestrel: side-by-side comparison
Diclofenac (NSAID (phenylacetic acid)) 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 | Diclofenac | Levonorgestrel |
|---|---|---|
| Therapeutic class | NSAID (phenylacetic acid) | Synthetic progestin (emergency contraception) |
| CAS | 15307-86-5 | 797-63-7 |
| ATC | M01AB05 | G03AC03 |
| Molecular weight | 296.15 g/mol | 312.5 g/mol |
| Brands with this active ingredient | 1 | 1 |
What they share
Diclofenac 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
Diclofenac 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
Diclofenac: Diclofenac reversibly inhibits cyclooxygenase enzymes COX-1 and COX-2, with somewhat greater selectivity for COX-2 than ibuprofen and naproxen. Levonorgestrel: In emergency contraception, levonorgestrel works primarily by delaying or inhibiting ovulation when taken before the LH surge.
Indications compared
Diclofenac: Diclofenac is approved in adults for the treatment of osteoarthritis, rheumatoid arthritis, ankylosing spondylitis, acute musculoskeletal pain, post-surgical pain, primary dysmenorrhoea, acute migraine and ureteric colic… Levonorgestrel: Levonorgestrel is approved for emergency contraception (single 1.5mg dose), regular oral contraception (combined with ethinylestradiol or as progestin-only), and as the active component of hormonal intrauterine devices f…
Safety profile
Diclofenac: Common adverse effects include gastrointestinal symptoms, headache, dizziness and elevated liver enzymes. Levonorgestrel: Common adverse effects of emergency contraceptive use include nausea, headache, fatigue, dizziness, breast tenderness and menstrual cycle changes.
Frequently asked questions
Is Diclofenac better than Levonorgestrel? ▾
Diclofenac and Levonorgestrel are not "better or worse" — they treat different things. The sensible question is which fits your specific need.
Can Diclofenac 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 Diclofenac
Products with Levonorgestrel
The information on this website is provided for reference and educational purposes only. It does not replace consultation with a qualified healthcare professional.