Famciclovir and Theophylline Interaction
Drug interaction information between Famciclovir and Theophylline.
Famciclovir and Theophylline have a documented minor interaction in FDA labeling.
FDA drug labeling documents a minor-severity interaction between Famciclovir 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
Studies show that theophylline does not change how the body breaks down or uses famciclovir.
FDA Label Information
7.2 Potential for Other Drugs to Affect Penciclovir No clinically significant alterations in penciclovir pharmacokinetics were observed following single-dose administration of 500 mg famciclovir after pretreatment with multiple doses of allopurinol, cimetidine, theophylline, zidovudine, promethazine, when given shortly after an antacid (magnesium and aluminum hydroxide), or concomitantly with emtricitabine.
Famciclovir Also Interacts With
- Allopurinol minor
- Digoxin minor
- Probenecid minor
- Cimetidine minor
- Promethazine 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 Famciclovir + 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 Famciclovir's 7. In the minor band specifically: Famciclovir has 7 (also Allopurinol, Digoxin, Probenecid, Cimetidine); Theophylline has 54 (also Propranolol, Methotrexate, Diazepam, Lithium).
What mechanism field is on file for Famciclovir and Theophylline?
Studies show that theophylline does not change how the body breaks down or uses famciclovir.
Theophylline carries more major-labeled pairs than Famciclovir
SPL source-record counts only. This page's band is minor · classes on file: Famciclovir (Antiviral (Nucleoside Analog)); Theophylline (Methylxanthine Bronchodilator).
Theophylline has 27 major-labeled pairs vs Famciclovir's 0. This page itself is in the minor band, not the major band.
0 major · 0 moderate · 7 minor · 7 total
- Other minor peers for Famciclovir
- Allopurinol
- Digoxin
- Probenecid
- Cimetidine
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.