How the interaction occurs:
When these two medicines are taken together, your body may process theophylline more quickly.
What might happen:
The blood level of your theophylline may decrease, so it may not work as well.
What you should do about this interaction:
Let your healthcare professionals know you are taking these medicines together. If your doctor prescribes these two medicines together, you may need your theophylline level checked to be sure you are receiving the right dose.If you have been medicines together on a regular schedule, and then the barbiturate (e.g. phenobarbital) or hydantoin (e.g. phenytoin) is stopped by your doctor, your may also need to have your theophylline level checked to make sure you are at a safe and effective dose.If you experience problems with your breathing, severe nausea/vomiting, tremors, heart palpitations or other effects, contact your doctor. It may be necessary to adjust the dose of your medicine.Your healthcare professionals (e.g. doctor or pharmacist) may already be aware of this drug interaction and may be monitoring you for it. Do not start, stop, or change the dosage of any medicine before checking with them first.
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