What the FDA labels say about taking them together
Etrasimod arginine and quinidine
Etrasimod arginine's FDA label of August 18, 2025 names quinidine in its drug interactions section; the quinidine label PlainMeds reads does not name etrasimod arginine. The etrasimod arginine label: “Prevention or Management; Seek the advice of a cardiologist before initiating VELSIPITY treatment with Class Ia, Class III anti-arrhythmic drugs, or other drugs that prolong the QT interval.”
Check it at the source: the etrasimod arginine FDA label on DailyMed (effective August 18, 2025, Pfizer Laboratories Div Pfizer Inc); the quinidine FDA label on DailyMed (effective February 1, 2018, Sun Pharmaceutical Industries, Inc.).
What does the etrasimod arginine label say about quinidine?
Etrasimod arginine label, drug interactionsPrevention or Management; Seek the advice of a cardiologist before initiating VELSIPITY treatment with Class Ia (e.g., quinidine, procainamide), Class III anti-arrhythmic drugs (e.g., amiodarone, sotalol), or other drugs that prolong the QT interval.
Source: FDA drug label (Velsipity), Pfizer Laboratories Div Pfizer Inc, effective August 18, 2025 (SPL set 65171e4a-d136-4abc-b08c-c40c1b486ff6), via openFDA; the full label on DailyMed
What does the quinidine label say about etrasimod arginine?
Quinidine's label (effective February 1, 2018) does not name etrasimod arginine in these sections. A label lists what its studies and reports found; it is not a complete list.
Source: FDA drug label (Quinidine Gluconate), Sun Pharmaceutical Industries, Inc., effective February 1, 2018 (SPL set 5023f053-fcc4-4c2c-aa59-9ec198ad185e), 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
| Etrasimod arginine | Quinidine | |
|---|---|---|
| Labeled for | Crohn's disease and ulcerative colitis | Atrial fibrillation |
| Boxed warning | No | Yes |
| Pharmacy cost (NADAC) | n/a | $4.92 per tablet 324 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