What the FDA labels say about taking them together
Dicyclomine and quinidine
Dicyclomine's FDA label of August 6, 2026 names quinidine in its drug interactions section; the quinidine label PlainMeds reads does not name dicyclomine. The dicyclomine label: “… dicyclomine hydrochloride: amantadine, antiarrhythmic agents of Class I (e.g., quinidine), antihistamines, antipsychotic agents (e.g., phenothiazines), benzodiazepines, MAO inhibitors, narcotic analgesics (e.g. …”
Check it at the source: the dicyclomine FDA label on DailyMed (effective August 6, 2026, Lannett Company, LLC); the quinidine FDA label on DailyMed (effective February 1, 2018, Sun Pharmaceutical Industries, Inc.).
What does the dicyclomine label say about quinidine?
Dicyclomine label, drug interactionsDrugs with Anticholinergic Activity The following agents may increase certain actions or side effects of anticholinergic drugs including dicyclomine hydrochloride: amantadine, antiarrhythmic agents of Class I (e.g., quinidine), antihistamines, antipsychotic agents (e.g., phenothiazines), benzodiazepines, MAO inhibitors, narcotic analgesics (e.g., meperidine), nitrates and nitrites, sympathomimetic agents, tricyclic antidepressants, and other drugs having anticholinergic activity.
Source: FDA drug label (Dicyclomine Hydrochloride), Lannett Company, LLC, effective August 6, 2026 (SPL set bd2cba10-70ec-4d1f-b46c-53d1de2ee130), via openFDA; the full label on DailyMed
What does the quinidine label say about dicyclomine?
Quinidine's label (effective February 1, 2018) does not name dicyclomine 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
| Dicyclomine | Quinidine | |
|---|---|---|
| Labeled for | Irritable bowel syndrome | Atrial fibrillation |
| Boxed warning | No | Yes |
| Pharmacy cost (NADAC) | $0.059 per tablet 20 mg tablet | $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