Erythromycin
Effects Management
Increase in theophylline serum effects with toxicity due to decreased theophylline metabolism. Theophylline serum concentrations should be closely monitored when erythromycin is added, discontinued or when dosing changes occur. Dosing adjustments of theophylline may be necessary.
 
Effects and precautions
Donít take with fruit juice or wine, which decrease the drugís effectiveness.