What the FDA labels say about taking them together
Fosamprenavir and quinidine
Fosamprenavir's FDA label of September 15, 2023 names quinidine in its drug interactions section; the quinidine label PlainMeds reads does not name fosamprenavir. The fosamprenavir label: “Therapeutic concentration monitoring, if available, is recommended for antiarrhythmics.”
Check it at the source: the fosamprenavir FDA label on DailyMed (effective September 15, 2023, Mylan Pharmaceuticals Inc.); the quinidine FDA label on DailyMed (effective February 1, 2018, Sun Pharmaceutical Industries, Inc.).
What does the fosamprenavir label say about quinidine?
Fosamprenavir label, drug interactionsConcomitant Drug Class/Drug Name: Antiarrhythmics: Amiodarone, disopyramide, lidocaine (systemic), and quinidine; Effect on Concentration of Amprenavir or Concomitant Drug: ↑ Antiarrhythmics; Clinical Comment: Therapeutic concentration monitoring, if available, is recommended for antiarrhythmics.
Source: FDA drug label (Fosamprenavir Calcium), Mylan Pharmaceuticals Inc., effective September 15, 2023 (SPL set 3a1424d8-844c-4e24-9ebd-b2c2b61b61a3), via openFDA; the full label on DailyMed
What does the quinidine label say about fosamprenavir?
Quinidine's label (effective February 1, 2018) does not name fosamprenavir 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
| Fosamprenavir | Quinidine | |
|---|---|---|
| Labeled for | HIV | 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