Take this medication by mouth as directed by your doctor, usually once or twice daily. Since different manufacturers have different ways to take this medication, ask your doctor or pharmacist about the best time(s) to take your brand of theophylline and if you should take the drug with or without food.

Do not crush or chew the capsules or tablets. Doing so can release all of the drug at once, increasing the risk of side effects. Also, do not split the tablets unless they have a score line and your doctor or pharmacist tells you to do so. Swallow the whole or split tablet without crushing or chewing.

The dosage is based on your medical condition, response to treatment, age, weight, lab tests (theophylline blood levels), and other medications you may be taking. Be sure to tell your doctor and pharmacist about all the products you use (including prescription drugs, nonprescription drugs, and herbal products). To reduce your risk of side effects, your doctor may direct you to start this medication at a low dose and gradually increase your dose. Follow your doctor's instructions carefully.

Certain diets (such as high protein/low carbohydrate or high carbohydrate/low protein) may change the effect of theophylline. Tell your doctor if you have any major changes in your diet. Your doctor may need to adjust your dose.

Take this medication regularly to get the most benefit from it. To help you remember, take it at the same time(s) each day. Keep taking this medication even if you feel well. Do not increase your dose, take this drug more often, or stop taking it without first consulting your doctor.

Get medical help right away if your asthma symptoms worsen or if you are using your quick-relief inhaler more than usual or more often than prescribed.