What the FDA labels say about taking them together
Cimetidine and pentoxifylline
Pentoxifylline's FDA label of May 15, 2026 names cimetidine in its drug interactions section; the cimetidine label PlainMeds reads does not name pentoxifylline. The pentoxifylline label: “Concomitant administration with cimetidine is reported to increase the average steady state plasma concentration of pentoxifylline (~25%) and the Metabolite I (~30%).”
Check it at the source: the cimetidine FDA label on DailyMed (effective July 15, 2026, Mylan Pharmaceuticals Inc.); the pentoxifylline FDA label on DailyMed (effective May 15, 2026, Rising Pharma Holdings, Inc.).
What does the cimetidine label say about pentoxifylline?
Cimetidine's label (effective July 15, 2026) does not name pentoxifylline in these sections. A label lists what its studies and reports found; it is not a complete list.
Source: FDA drug label (Cimetidine), Mylan Pharmaceuticals Inc., effective July 15, 2026 (SPL set 06c0a509-026f-44e0-9975-a94a8de51d43), via openFDA; the full label on DailyMed
What does the pentoxifylline label say about cimetidine?
Pentoxifylline label, drug interactionsConcomitant administration with cimetidine is reported to increase the average steady state plasma concentration of pentoxifylline (~25%) and the Metabolite I (~30%).
Source: FDA drug label (Pentoxifylline), Rising Pharma Holdings, Inc., effective May 15, 2026 (SPL set cd840a2c-2a0e-4b2b-84ff-a0406bb6fa37), 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
| Cimetidine | Pentoxifylline | |
|---|---|---|
| Labeled for | Acid reflux and ulcers | n/a |
| Boxed warning | No | No |
| Pharmacy cost (NADAC) | $0.236 per tablet 300 mg tablet | $0.227 per tablet 400 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