What the FDA labels say about taking them together
Methacholine and theophylline
Methacholine's FDA label of July 15, 2026 names theophylline in its drug interactions section; the theophylline label PlainMeds reads does not name methacholine.
Check it at the source: the methacholine FDA label on DailyMed (effective July 15, 2026, Methapharm Inc.); the theophylline FDA label on DailyMed (effective March 10, 2026, Strides Pharma Science Limited).
What does the methacholine label say about theophylline?
Methacholine label, drug interactionsBeta-Agonists, Anticholinergics, and Theophylline Beta-agonists, anticholinergics, and theophylline inhibit the response of airways to Provocholine; therefore, hold these drugs before Provocholine use for the following duration:
Source: FDA drug label (Provocholine), Methapharm Inc., effective July 15, 2026 (SPL set e8983096-65e6-41f2-8b6f-bbf0a7227307), via openFDA; the full label on DailyMed
What does the theophylline label say about methacholine?
Theophylline's label (effective March 10, 2026) does not name methacholine in these sections. A label lists what its studies and reports found; it is not a complete list.
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
| Methacholine | Theophylline | |
|---|---|---|
| Labeled for | n/a | Asthma |
| Boxed warning | Yes | No |
| Pharmacy cost (NADAC) | n/a | $0.330 per tablet 300 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