Theophylline and Erythromycin Interaction
Drug interaction information between Theophylline and Erythromycin.
Theophylline and Erythromycin have a documented minor interaction in FDA labeling.
FDA drug labeling documents a minor-severity interaction between Theophylline and Erythromycin. This page displays the available source-record category and label text. The category is not an individual risk estimate or medication-combination direction.
How They Interact
Erythromycin stops the liver from breaking down theophylline properly. This causes theophylline to stay in your system longer and reach higher levels.
FDA Label Information
If theophylline is being initiated in a patient who is already taking a drug that inhibits theophylline clearance (e.g., cimetidine, erythromycin), the dose of theophylline required to achieve a therapeutic serum theophylline concentration will be smaller. 40% increase Clarithromycin Similar to erythromycin. Erythromycin Erythromycin metabolite decreases theophylline clearance by inhibiting cytochrome P450 3A3.
Theophylline Also Interacts With
- Metoprolol major
- Albuterol major
- Omeprazole major
- Amoxicillin major
- Famotidine major
Erythromycin Also Interacts With
- Eplerenone major
- Pitavastatin major
- Risperidone major
- Sildenafil major
- Lefamulin moderate
Frequently Asked Questions
What SPL severity band is on file for Theophylline + Erythromycin?
Compiled FDA labeling labels this pair minor. That is a source-record field, not an individual medication-combination decision.
Which drug in this pair has the larger labeled-interaction portfolio?
Theophylline has 86 labeled pairs on file vs Erythromycin's 63. In the minor band specifically: Theophylline has 54 (also Propranolol, Methotrexate, Diazepam, Lithium); Erythromycin has 53 (also Acetaminophen/Oxycodone, Alprazolam, Atorvastatin, Bromocriptine).
What mechanism field is on file for Theophylline and Erythromycin?
Erythromycin stops the liver from breaking down theophylline properly. This causes theophylline to stay in your system longer and reach higher levels.
Theophylline carries more major-labeled pairs than Erythromycin
SPL source-record counts only. This page's band is minor · classes on file: Theophylline (Methylxanthine Bronchodilator); Erythromycin (Macrolide Antibiotic).
Theophylline has 27 major-labeled pairs vs Erythromycin's 4. This page itself is in the minor band, not the major band.
27 major · 5 moderate · 54 minor · 86 total
- Other minor peers for Theophylline
- Propranolol
- Methotrexate
- Diazepam
- Lithium
4 major · 6 moderate · 53 minor · 63 total
- Other minor peers for Erythromycin
- Acetaminophen/Oxycodone
- Alprazolam
- Atorvastatin
- Bromocriptine
Sources: FDA Drug Labels (SPL) via openFDA (2026). This is for informational purposes only and is not medical advice. This registry does not provide individual medication-combination directions.
Read our methodology - how this data is sourced, computed, and verified.