What the FDA labels say about taking them together
Quinidine and verapamil
Quinidine's FDA label of February 1, 2018 names verapamil in its drug interactions section, and verapamil's label names quinidine too. The verapamil label: “Concomitant administration of quinidine preceded the severe hypotension in 3 of the 8 patients.”
Check it at the source: the quinidine FDA label on DailyMed (effective February 1, 2018, Sun Pharmaceutical Industries, Inc.); the verapamil FDA label on DailyMed (effective April 6, 2026, Zydus Pharmaceuticals (USA) Inc.).
What does the quinidine label say about verapamil?
Quinidine label, drug interactionsHepatic clearance of quinidine is significantly reduced during coadministration of verapamil, with corresponding increases in serum levels and half-life.
Quinidine label, warningsThis hazard may be decreased if partial atrioventricular block is achieved prior to initiation of quinidine therapy, using conduction-reducing drugs such as digitalis, verapamil, diltiazem, or a β-receptor blocking agent.
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
What does the verapamil label say about quinidine?
Verapamil label, drug interactionsIn a small number of patients with hypertrophic cardiomyopathy (IHSS), concomitant use of verapamil and quinidine resulted in significant hypotension.
Verapamil label, warningsConcomitant administration of quinidine (see PRECAUTIONS, Drug interactions ) preceded the severe hypotension in 3 of the 8 patients (2 of whom developed pulmonary edema).
Source: FDA drug label (Verapamil Hydrochloride, NDA020943), Wilshire Pharmaceuticals, Inc., effective November 27, 2024 (SPL set 5f665d08-e1e4-422a-88c2-d8834abf9e1a), via openFDA
Source: FDA drug label (Verapamil hydrochloride), Zydus Pharmaceuticals (USA) Inc., effective April 6, 2026 (SPL set e19ab8d8-dae5-489d-9805-7e7407bea06d), 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
| Quinidine | Verapamil | |
|---|---|---|
| Labeled for | Atrial fibrillation | High blood pressure, Atrial fibrillation, Angina |
| Boxed warning | Yes | No |
| Pharmacy cost (NADAC) | $4.92 per tablet 324 mg tablet | $0.191 per tablet 180 mg tablet |
| Shortage now | No current entry | A presentation being discontinued |
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