What the FDA labels say about taking them together
Aminophylline and metronidazole
Aminophylline's FDA label of May 22, 2026 names metronidazole in its drug interactions section; the metronidazole labels PlainMeds reads (4) do not name aminophylline. The aminophylline label: “… ketoconazole; lomefloxacin mebendazole medroxyprogesterone methylprednisolone metronidazole metoprolol nadolol nifedipine nizatidine norfloxacin ofloxacin omeprazole prednisone, prednisolone ranitidine rifabutin …”
Check it at the source: the aminophylline FDA label on DailyMed (effective May 22, 2026, Hospira, Inc.); the metronidazole FDA label on DailyMed (effective September 3, 2024, Aurobindo Pharma Limited).
What does the aminophylline label say about metronidazole?
Aminophylline label, drug interactionsalbuterol, systemic and inhaled amoxicillin ampicillin, with or without sulbactam atenolol azithromycin caffeine, dietary ingestion cefaclor co-trimoxazole (trimethoprim and sulfamethoxazole) diltiazem dirithromycin enflurane famotidine felodipine finasteride hydrocortisone isoflurane isoniazid isradipine influenza vaccine ketoconazole; lomefloxacin mebendazole medroxyprogesterone methylprednisolone metronidazole metoprolol nadolol nifedipine nizatidine norfloxacin ofloxacin omeprazole prednisone, prednisolone ranitidine rifabutin roxithromycin sorbitol (purgative doses do not inhibit theophylline absorption) sucralfate terbutaline, systemic terfenadine tetracycline tocainide
Source: FDA drug label (Aminophylline), Hospira, Inc., effective May 22, 2026 (SPL set 9a663ef3-881f-48bd-2689-3713b24545c2), via openFDA; the full label on DailyMed
What does the metronidazole label say about aminophylline?
Metronidazole's label (effective September 3, 2024) and its 3 other brand-application labels do not name aminophylline in these sections. A label lists what its studies and reports found; it is not a complete list.
Source: FDA drug label (Metronidazole), Aurobindo Pharma Limited, effective September 3, 2024 (SPL set f68397ee-67db-472e-8607-4300064e37df), 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
| Aminophylline | Metronidazole | |
|---|---|---|
| Labeled for | Asthma | Bacterial infections |
| Boxed warning | No | Yes |
| Pharmacy cost (NADAC) | n/a | $0.102 per tablet 250 mg tablet |
| Shortage now | No current entry | In shortage |
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