What the FDA labels say about taking them together
Ketamine and theophylline
Ketamine's FDA label of March 27, 2026 names theophylline in its drug interactions section, and theophylline's label names ketamine too. The theophylline label: “20% decrease Ketamine Pharmacologic.”
Check it at the source: the ketamine FDA label on DailyMed (effective March 27, 2026, Par Health USA, LLC); the theophylline FDA label on DailyMed (effective March 10, 2026, Strides Pharma Science Limited).
What does the ketamine label say about theophylline?
Ketamine label, drug interactionsDRUG INTERACTIONS Theophylline or Aminophylline: Do not co-administer with KETALAR as concomitant use may lower the seizure threshold ( 7.1 ).
Ketamine label, warnings and precautionsTheophylline or Aminophylline: Concomitant administration of KETALAR and theophylline or aminophylline may lower the seizure threshold [see Drug Interactions ( 7.1 )].
Source: FDA drug label (Ketalar), Par Health USA, LLC, effective March 27, 2026 (SPL set 14e8f864-8b8a-4e7e-8439-e510d3107063), via openFDA; the full label on DailyMed
What does the theophylline label say about ketamine?
Theophylline label, drug interactions20% decrease Ketamine Pharmacologic.
Source: FDA drug label (Theophylline), Strides Pharma Science Limited, effective March 10, 2026 (SPL set b7a90ccf-9c32-40cc-9008-7e55b3da4dfd), 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
| Ketamine | Theophylline | |
|---|---|---|
| Labeled for | n/a | Asthma |
| Boxed warning | No | No |
| Pharmacy cost (NADAC) | $0.556 per mL 500 mg/10 mL vial | $0.330 per tablet 300 mg tablet |
| Shortage now | A presentation being discontinued | 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