zafirlukast and Aquaphyllin Interactions

Interactions between zafirlukast and Aquaphyllin (theophylline)

theophylline and zafirlukast (Moderate Drug-Drug)

MONITOR: Limited clinical data suggest that zafirlukast may significantly increase theophylline serum concentrations. In addition, theophylline coadministration with zafirlukast may reduce zafirlukast plasma concentrations. The mechanism is unknown. A single study in 13 asthmatic patients reported a 30% decrease in mean zafirlukast concentration. The clinical significance of this reduction is unclear.

MANAGEMENT: If there is any change in either drug's regimen, the patient should be observed for altered theophylline and zafirlukast effect, and theophylline levels should be monitored closely. Other methylxanthines may interact with zafirlukast in a similar manner.