What the FDA labels say about taking them together
Drospirenone/ethinyl estradiol and tizanidine
Drospirenone/ethinyl estradiol's FDA label of May 29, 2025 names tizanidine in its drug interactions section; the tizanidine labels PlainMeds reads (3) do not name drospirenone/ethinyl estradiol. The drospirenone/ethinyl estradiol label: “COCs Increasing the Plasma Concentrations of CYP450 Enzymes: In clinical studies, administration of a hormonal contraceptive containing EE did not lead to any increase or only to a weak increase in plasma concentrations …”
Check it at the source: the drospirenone/ethinyl estradiol FDA label on DailyMed (effective May 29, 2025, Bayer HealthCare Pharmaceuticals Inc.); the tizanidine FDA label on DailyMed (effective January 2, 2026, Legacy Pharma USA, Inc.).
What does the drospirenone/ethinyl estradiol label say about tizanidine?
Drospirenone/ethinyl estradiol label, drug interactionsCOCs Increasing the Plasma Concentrations of CYP450 Enzymes: In clinical studies, administration of a hormonal contraceptive containing EE did not lead to any increase or only to a weak increase in plasma concentrations of CYP3A4 substrates (e.g., midazolam) while plasma concentrations of CYP2C19 substrates (e.g., omeprazole and voriconazole) and CYP1A2 substrates (e.g., theophylline and tizanidine) can have a weak or moderate increase.
Source: FDA drug label (Yaz), Bayer HealthCare Pharmaceuticals Inc., effective May 29, 2025 (SPL set 065f33e4-b587-4e66-b896-ca9ab7b7c876), via openFDA; the full label on DailyMed
What does the tizanidine label say about drospirenone/ethinyl estradiol?
Tizanidine's label (effective January 2, 2026) and its 2 other brand-application labels do not name drospirenone/ethinyl estradiol 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
| Drospirenone/ethinyl estradiol | Tizanidine | |
|---|---|---|
| Labeled for | Acne, Birth control | Muscle spasms and spasticity |
| Boxed warning | Yes | No |
| Pharmacy cost (NADAC) | $0.151 per tablet 3-0.03 mg 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