A change in brand or formulation may necessitate a different dosage. Avoid eating excessive amounts of grilled or char-broiled foods. These foods may affect how much theophylline you need. Talk to your doctor before making changes in your diet. Avoid excessive use of caffeinated beverages such as coffee, tea, and cola.
Theophylline is related chemically to caffeine.
You may experience some side effects if you consume too much caffeine. Other, less serious side effects may occur, although they are not common at appropriate doses. Side effects other than those listed here may also occur. Talk to your doctor about any side effect that seems unusual or that is especially bothersome. Guaifenesin and theophylline interacts with many other drugs.