What the FDA labels say about taking them together
Amiodarone and tizanidine
Tizanidine's FDA label of January 2, 2026 names amiodarone in its drug interactions section; the amiodarone labels PlainMeds reads (2) do not name tizanidine. The tizanidine label: “Adverse reactions such as hypotension, bradycardia, or excessive drowsiness can occur when Zanaflex is taken with other CYP1A2 inhibitors, such as zileuton, fluoroquinolones other than ciprofloxacin (which is …”
Check it at the source: the amiodarone FDA label on DailyMed (effective December 9, 2025, Chartwell RX, LLC); the tizanidine FDA label on DailyMed (effective January 2, 2026, Legacy Pharma USA, Inc.).
What does the amiodarone label say about tizanidine?
Amiodarone's label (effective December 9, 2025) and its 1 other brand-application label do not name tizanidine in these sections. A label lists what its studies and reports found; it is not a complete list.
Source: FDA drug label (Amiodarone Hydrochloride), Chartwell RX, LLC, effective December 9, 2025 (SPL set 5520f11d-968d-4f4f-bf57-d14369c0d746), via openFDA; the full label on DailyMed
What does the tizanidine label say about amiodarone?
Tizanidine label, drug interactionsConcomitant use of Zanaflex with moderate or weak CYP1A2 inhibitors (e.g., zileuton, antiarrhythmics [amiodarone, mexiletine, propafenone, and verapamil], cimetidine, famotidine, oral contraceptives, acyclovir, and ticlopidine) should be avoided.
Zanaflex label (Covis Pharma US, Inc, May 5, 2025), drug interactionsInhibitors other than Fluvoxamine and Ciprofloxacin Because of potential drug interactions, concomitant use of Zanaflex with other CYP1A2 inhibitors, such as zileuton, fluoroquinolones other than strong CYP1A2 inhibitors (which are contraindicated), antiarrhythmics (amiodarone, mexiletine, propafenone, and verapamil), cimetidine, famotidine, oral contraceptives, acyclovir, and ticlopidine) should be avoided.
Zanaflex label (Covis Pharma US, Inc, May 5, 2025), warnings and precautionsAdverse reactions such as hypotension, bradycardia, or excessive drowsiness can occur when Zanaflex is taken with other CYP1A2 inhibitors, such as zileuton, fluoroquinolones other than ciprofloxacin (which is contraindicated), antiarrhythmics (amiodarone, mexiletine, propafenone), cimetidine, famotidine, oral contraceptives, acyclovir, and ticlopidine).
Ontralfy label (Rosemont Pharmaceuticals, LLC, October 25, 2025), drug interactionsConcomitant use of Ontralfy with moderate or weak CYP1A2 inhibitors (e.g., zileuton, antiarrhythmics [amiodarone, mexiletine, propafenone, and verapamil], cimetidine, famotidine, oral contraceptives, acyclovir, and ticlopidine) should be avoided.
Source: FDA drug label (Zanaflex, NDA020397), Covis Pharma US, Inc, effective May 5, 2025 (SPL set 043d9e51-bfa2-4add-9058-5ece332f7e99), via openFDA
Source: FDA drug label (Ontralfy, NDA216190), Rosemont Pharmaceuticals, LLC, effective October 25, 2025 (SPL set 7b88c338-c0b7-4c08-bef6-a4ffc2f25df7), via openFDA
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
| Amiodarone | Tizanidine | |
|---|---|---|
| Labeled for | n/a | Muscle spasms and spasticity |
| Boxed warning | Yes | No |
| Pharmacy cost (NADAC) | $0.122 per tablet 200 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