The theophylline in this medicine may add to the central nervous system stimulant effects of caffeine-containing foods or beverages such as chocolate, cocoa, tea, coffee, and cola drinks. Avoid eating or drinking large amounts of these foods or beverages while taking this medicine. If you have any questions about this, check with your doctor.
The phenobarbital in this medicine will add to the effects of alcohol and other CNS depressants (medicines that slow down the nervous system, possibly causing drowsiness). Some examples of CNS depressants are antihistamines or medicine for hay fever, other allergies, or colds; sedatives, tranquilizers, or sleeping medicine; prescription pain medicine or narcotics; other barbiturates; medicine for seizures; muscle relaxants; or anesthetics, including some dental anesthetics. Check with your doctor before taking any of the above while you are using this medicine.
A change in your usual behavior or physical well-being may affect the way this medicine works in your body. Check with your doctor if you:
- have a fever of 102 °F or higher for at least 24 hours or higher than 100 °F for longer than 24 hours.
- start or stop smoking.
- start or stop taking another medicine.
- change your diet for a long time.
Before you have myocardial perfusion studies (a medical test that shows how well blood is flowing to your heart), tell the medical doctor in charge that you are taking this medicine. The results of the test may be affected by this medicine.
This medicine may cause some people to become dizzy, lightheaded, drowsy, or less alert than they are normally. Make sure you know how you react to this medicine before you drive, use machines, or do anything else that could be dangerous if you are dizzy or are not alert.