What the FDA labels say about taking them together
Atropine/difenoxin and meperidine
Atropine/difenoxin's FDA label of March 23, 2026 names meperidine in its drug interactions section; the meperidine labels PlainMeds reads (2) do not name atropine/difenoxin.
Check it at the source: the atropine/difenoxin FDA label on DailyMed (effective March 23, 2026, Legacy Pharma USA Inc.); the meperidine FDA label on DailyMed (effective November 29, 2025, EPIC PHARMA, LLC).
What does the atropine/difenoxin label say about meperidine?
Atropine/difenoxin label, drug interactionsDrug Interactions Since the chemical structure of difenoxin hydrochloride is similar to meperidine hydrochloride, the concurrent use of MOTOFEN ® with monoamine oxidase inhibitors may, in theory, precipitate a hypertensive crisis.
Source: FDA drug label (Motofen), Legacy Pharma USA Inc., effective March 23, 2026 (SPL set 1fa11c67-5492-469c-9475-6bfa0e5e9ff8), via openFDA; the full label on DailyMed
What does the meperidine label say about atropine/difenoxin?
Meperidine's label (effective November 29, 2025) and its 1 other brand-application label do not name atropine/difenoxin in these sections. A label lists what its studies and reports found; it is not a complete list.
Source: FDA drug label (Meperidine Hydrochloride), EPIC PHARMA, LLC, effective November 29, 2025 (SPL set fae5cc34-5917-4445-9516-25f97ffca8db), 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
| Atropine/difenoxin | Meperidine | |
|---|---|---|
| Labeled for | Diarrhea | Pain |
| Boxed warning | No | Yes |
| Pharmacy cost (NADAC) | $6.91 per tablet 1-0.025 mg tablet | $0.157 per mL 50 mg/5 mL solution |
| Shortage now | No current entry | Listed; available |
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