What the FDA labels say about taking them together
Ethinyl estradiol/ferrous fumarate/levonorgestrel and tizanidine
Ethinyl estradiol/ferrous fumarate/levonorgestrel's FDA label of October 18, 2024 names tizanidine in its drug interactions section; the tizanidine labels PlainMeds reads (3) do not name ethinyl estradiol/ferrous fumarate/levonorgestrel. The ethinyl estradiol/ferrous fumarate/levonorgestrel label: “Contraceptives on Other Drugs Combined oral contraceptives containing EE may inhibit the metabolism of other compounds and increase their plasma concentrations.”
Check it at the source: the ethinyl estradiol/ferrous fumarate/levonorgestrel FDA label on DailyMed (effective October 18, 2024, Xiromed, LLC); the tizanidine FDA label on DailyMed (effective January 2, 2026, Legacy Pharma USA, Inc.).
What does the ethinyl estradiol/ferrous fumarate/levonorgestrel label say about tizanidine?
Ethinyl estradiol/ferrous fumarate/levonorgestrel label, drug interactionsContraceptives on Other Drugs Combined oral contraceptives containing EE may inhibit the metabolism of other compounds (e.g., cyclosporine, prednisolone, theophylline, tizanidine, and voriconazole) and increase their plasma concentrations.
Source: FDA drug label (Joyeaux), Xiromed, LLC, effective October 18, 2024 (SPL set 655b2c93-cfae-d44f-c128-c816bbd88e45), via openFDA; the full label on DailyMed
What does the tizanidine label say about ethinyl estradiol/ferrous fumarate/levonorgestrel?
Tizanidine's label (effective January 2, 2026) and its 2 other brand-application labels do not name ethinyl estradiol/ferrous fumarate/levonorgestrel 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/ferrous fumarate/levonorgestrel | Tizanidine | |
|---|---|---|
| Labeled for | Birth control | Muscle spasms and spasticity |
| Boxed warning | Yes | No |
| Pharmacy cost (NADAC) | $3.45 per tablet 28 tablet | $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