What the FDA labels say about taking them together
Loperamide and quinidine
Loperamide's FDA label of June 3, 2026 names quinidine in its drug interactions (prescription label) section; the quinidine label PlainMeds reads does not name loperamide. The loperamide label: “DRUG INTERACTIONS Effects of Other Drugs on Loperamide Concomitant use of Loperamide Hydrochloride Capsules with inhibitors of CYP3A4 (e.g., itraconazole) or CYP2C8 (e.g., gemfibrozil) or inhibitors of P-glycoprotein …”
Check it at the source: the loperamide FDA label on DailyMed (effective June 3, 2026, Aurobindo Pharma Limited); the quinidine FDA label on DailyMed (effective February 1, 2018, Sun Pharmaceutical Industries, Inc.).
What does the loperamide label say about quinidine?
Loperamide label, drug interactions (prescription label)DRUG INTERACTIONS Effects of Other Drugs on Loperamide Concomitant use of Loperamide Hydrochloride Capsules with inhibitors of CYP3A4 (e.g., itraconazole) or CYP2C8 (e.g., gemfibrozil) or inhibitors of P-glycoprotein (e.g., quinidine, ritonavir) can increase exposure to loperamide.
Source: FDA drug label (Loperamide Hydrochloride), Aurobindo Pharma Limited, effective June 3, 2026 (SPL set 8e4004be-bf79-4631-9e38-c4e7b6726313), via openFDA; the full label on DailyMed
What does the quinidine label say about loperamide?
Quinidine's label (effective February 1, 2018) does not name loperamide 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
| Loperamide | Quinidine | |
|---|---|---|
| Labeled for | Diarrhea | Atrial fibrillation |
| Boxed warning | Yes | Yes |
| Pharmacy cost (NADAC) | $0.0549 per capsule 2 mg capsule | $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