Pegin Peginterferon alfa-2a [Pegylated Interferon alfa-2a] Theophylline
ModeratePeginterferon alfa-2a can raise the level of theophylline in the blood, because theophylline is broken down by the CYP1A2 enzyme. If you take both, theophylline levels should be monitored and the theophylline dose adjusted accordingly.
These medicines are often taken together with some care. Your doctor may change a dose, space them apart or check on you more often. Make sure your doctor and pharmacist know you take both.