What the FDA labels say about taking them together
Ethinyl estradiol/etonogestrel and tizanidine
Ethinyl estradiol/etonogestrel's FDA label of November 14, 2025 names tizanidine in its drug interactions section; the tizanidine labels PlainMeds reads (3) do not name ethinyl estradiol/etonogestrel. The ethinyl estradiol/etonogestrel label: “Effects of CHCs on Other Drugs CHCs containing ethinyl estradiol may inhibit the metabolism of other compounds and increase their plasma concentrations.”
Check it at the source: the ethinyl estradiol/etonogestrel FDA label on DailyMed (effective November 14, 2025, Organon LLC); the tizanidine FDA label on DailyMed (effective January 2, 2026, Legacy Pharma USA, Inc.).
What does the ethinyl estradiol/etonogestrel label say about tizanidine?
Ethinyl estradiol/etonogestrel label, drug interactionsEffects of CHCs on Other Drugs CHCs containing ethinyl estradiol may inhibit the metabolism of other compounds (e.g., cyclosporine, prednisolone, theophylline, tizanidine, and voriconazole) and increase their plasma concentrations.
Source: FDA drug label (NuvaRing), Organon LLC, effective November 14, 2025 (SPL set 55eb60e3-6f4d-40a3-8ee6-e7fd2d0c7d97), via openFDA; the full label on DailyMed
What does the tizanidine label say about ethinyl estradiol/etonogestrel?
Tizanidine's label (effective January 2, 2026) and its 2 other brand-application labels do not name ethinyl estradiol/etonogestrel in these sections. A label lists what its studies and reports found; it is not a complete list.
Source: FDA drug label (Zanaflex), Legacy Pharma USA, Inc., effective January 2, 2026 (SPL set 60c27d35-7349-4fc6-86ad-70fffdbe3e08), via openFDA; the full label on DailyMed
These are the labels' own sentences. PlainMeds does not grade interactions; a pharmacist or prescriber can say what they mean for one person's medicines.
Both medicines on the record
| Ethinyl estradiol/etonogestrel | Tizanidine | |
|---|---|---|
| Labeled for | Birth control | Muscle spasms and spasticity |
| Boxed warning | Yes | No |
| Pharmacy cost (NADAC) | $46.35 per ring Etonogestrel-ee vaginal ring | $0.0331 per tablet 4 mg tablet |
| Shortage now | No current entry | No current entry |
Source: FDA NDC Directory, CMS NADAC of October 7, 2026 and the FDA Drug Shortage Database (FDA files October 8, 2026)
What next?
- Check more medicines together
- up to five at once