What the FDA labels say about taking them together
Atropine/diphenoxylate and meperidine
Atropine/diphenoxylate's FDA label of February 23, 2026 names meperidine in its warnings section; the meperidine labels PlainMeds reads (2) do not name atropine/diphenoxylate.
Check it at the source: the atropine/diphenoxylate FDA label on DailyMed (effective February 23, 2026, Pfizer Laboratories Div Pfizer Inc); the meperidine FDA label on DailyMed (effective November 29, 2025, EPIC PHARMA, LLC).
What does the atropine/diphenoxylate label say about meperidine?
Atropine/diphenoxylate label, warningsInteraction with Meperidine Hydrocholoride Since the chemical structure of diphenoxylate hydrochloride is similar to that of meperidine hydrochloride, the concurrent use of Lomotil with monoamine oxidase (MAO) inhibitors may, in theory, precipitate hypertensive crisis.
Source: FDA drug label (Lomotil), Pfizer Laboratories Div Pfizer Inc, effective February 23, 2026 (SPL set f170584a-1072-4fd7-b1dc-6756703483b9), via openFDA; the full label on DailyMed
What does the meperidine label say about atropine/diphenoxylate?
Meperidine's label (effective November 29, 2025) and its 1 other brand-application label do not name atropine/diphenoxylate 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/diphenoxylate | Meperidine | |
|---|---|---|
| Labeled for | Diarrhea | Pain |
| Boxed warning | No | Yes |
| Pharmacy cost (NADAC) | $0.139 per tablet 2.5-0.025 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