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Does Theophylline Interact with Erythromycin Ethylsuccinate?

Theophylline and Erythromycin Ethylsuccinate have a major drug interaction according to U.S. FDA drug labeling data. Erythromycin may increase serum theophylline levels, potentially causing toxicity. Theophylline may decrease erythromycin concentrations by ~35%, resulting in subtherapeutic erythromycin levels. The mechanism involves unknown mechanism for decreased erythromycin concentrations; theophylline toxicity likely due to cyp3a inhibition. Patients taking both medications should consult their healthcare provider before starting, stopping, or changing the dosage of either drug. This information is based on official FDA drug labeling sourced from OpenFDA and the NIH National Library of Medicine.

Severity
Major
Theophylline Class
Methylxanthine
Management
Close medical supervision required
Data Source
U.S. FDA via OpenFDA

How This Interaction Works

The interaction between Theophylline and Erythromycin Ethylsuccinate occurs because unknown mechanism for decreased erythromycin concentrations; theophylline toxicity likely due to cyp3a inhibition. Clinically, this means erythromycin may increase serum theophylline levels, potentially causing toxicity. theophylline may decrease erythromycin concentrations by ~35%, resulting in subtherapeutic erythromycin levels. This is classified as a major interaction, meaning it could cause serious harm if not properly managed. Your healthcare provider may need to adjust dosages, substitute one medication, or increase monitoring frequency.

What To Tell Your Doctor or Pharmacist

If you are taking Theophylline and your doctor is considering prescribing Erythromycin Ethylsuccinate (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
💊 Theophylline(Theophylline)+💊 Erythromycin Ethylsuccinate(E.E.S 400)

Severity & Interaction Details

⚠️
major
Use with caution — major interaction
Serious risk of clinically significant harm. Generally avoid; if used, monitor closely.
Severity scale
MinorContra
On record
Yes
Drug A class
Methylxanthine
Drug B class
—
Source
NLP:erythromycin ethylsuccinate

What this means in plain English

Erythromycin may increase serum theophylline levels, potentially causing toxicity. Theophylline may decrease erythromycin concentrations by ~35%, resulting in subtherapeutic erythromycin levels.

What the FDA label says

"Unknown mechanism for decreased erythromycin concentrations; theophylline toxicity likely due to CYP3A inhibition"

📖 Source: NLP:erythromycin ethylsuccinate

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Data sourced from U.S. FDA drug labeling via openFDA and the NIH National Library of Medicine. For informational purposes only. Always consult your pharmacist or physician.