Allopurinol and Theophylline Interaction
Drug interaction information between Allopurinol and Theophylline.
Allopurinol and Theophylline have a documented minor interaction in FDA labeling.
FDA drug labeling documents a minor-severity interaction between Allopurinol and Theophylline. 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
Taking high doses of allopurinol can make it harder for the body to get rid of theophylline. This can lead to higher levels of theophylline in your system.
FDA Label Information
Theophylline Clinical Impact Concomitant use of allopurinol doses greater than or equal to 600 mg/day may decrease the clearance of theophylline. Intervention Monitor and adjust theophylline doses as reflected in the prescribing information.
Allopurinol Also Interacts With
- Pegloticase major
- Cyclosporine moderate
- Amoxicillin moderate
- Amoxicillin/Clavulanate moderate
- Warfarin minor
Theophylline Also Interacts With
- Metoprolol major
- Albuterol major
- Omeprazole major
- Amoxicillin major
- Famotidine major
Frequently Asked Questions
What SPL severity band is on file for Allopurinol + Theophylline?
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 Allopurinol's 10. In the minor band specifically: Allopurinol has 6 (also Warfarin, Ampicillin/Sulbactam, Famciclovir, Prazosin); Theophylline has 54 (also Propranolol, Methotrexate, Diazepam, Lithium).
What mechanism field is on file for Allopurinol and Theophylline?
Taking high doses of allopurinol can make it harder for the body to get rid of theophylline. This can lead to higher levels of theophylline in your system.
Theophylline carries more major-labeled pairs than Allopurinol
SPL source-record counts only. This page's band is minor · classes on file: Allopurinol (Xanthine Oxidase Inhibitor); Theophylline (Methylxanthine Bronchodilator).
Theophylline has 27 major-labeled pairs vs Allopurinol's 1. This page itself is in the minor band, not the major band.
1 major · 3 moderate · 6 minor · 10 total
- Other minor peers for Allopurinol
- Warfarin
- Ampicillin/Sulbactam
- Famciclovir
- Prazosin
27 major · 5 moderate · 54 minor · 86 total
- Other minor peers for Theophylline
- Propranolol
- Methotrexate
- Diazepam
- Lithium
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.