Does Theophylline Interact with Cimetidine Hydrochloride?
CDI records a major classification for Theophylline and Cimetidine Hydrochloride. The stored summary is: Cimetidine reduces hepatic metabolism of theophylline, increasing blood levels. Adverse clinical effects reported; monitoring recommended regardless of cimetidine dosing. The mechanism involves inhibition of microsomal enzyme metabolism. Patients taking both medications should consult their healthcare provider before starting, stopping, or changing the dosage of either drug. This record was extracted from drug labeling through openFDA. NIH/NLM RxNorm is used for drug identities. The summary and severity classification are CDI's processed information, not a verbatim source quotation. Product, route, and patient circumstances matter.
Evidence status
A current label comparison is not yet available for this record. The summary and severity are stored CDI information; they have not been independently validated on this page against the exact product label.
Confirm the medicine, formulation, route, and applicable warning with your pharmacist or prescriber. Independent clinical review has not been recorded.
Saved label reference on DailyMed. This identifier has not been checked here as support for the current claim.
- Stored CDI classification
- Major
- Theophylline Class
- Methylxanthine
- Management
- Confirm exact products with your pharmacist
- Data Source
- U.S. FDA via OpenFDA
Recorded Mechanism
Inhibition of microsomal enzyme metabolism
What To Tell Your Doctor or Pharmacist
If you are taking Theophylline and your doctor is considering prescribing Cimetidine Hydrochloride (or vice versa), make sure to:
- Inform your doctor and pharmacist of all current medications, including over-the-counter drugs and supplements
- Ask whether the benefits of combining these medications outweigh the risks for your specific situation
- Ask what symptoms to watch for that would indicate the interaction is causing problems
- Ask how frequently you should be monitored while these are co-prescribed
- Ask whether any dosage adjustments are needed
- Never stop or change either medication without first consulting your healthcare provider