Your doctor or pharmacist may already be aware of any possible drug interactions and may be monitoring you for them. Do not start, stop, or change the dosage of any medicine before checking with your doctor or pharmacist first.
Before using this medication, tell your doctor or pharmacist of all prescription and nonprescription/herbal products you may use, especially of: adenosine, adrenaline-like drugs (e.g., ephedrine, phenylephrine, pseudoephedrine), allopurinol, aminoglutethimide, certain antiarrhythmic drugs (e.g., mexiletine, propafenone), anti-seizure drugs (e.g., carbamazepine, phenytoin, phenobarbital), benzodiazepines (e.g., diazepam, flurazepam), certain beta blockers (e.g., propranolol), birth control pills, cimetidine, digoxin, disulfiram, fluvoxamine, interferon, isoproterenol, moricizine, pentoxifylline, riociguat, rifampin, St John's wort, sulfinpyrazone, tacrine, thiabendazole, ticlopidine, verapamil, zileuton.
Check the labels on all your medicines (e.g., cough-and-cold products, diet aids) because they may contain ingredients that could increase the side effects of this medication. Ask your pharmacist about using those products safely.
Tobacco/marijuana smoking decreases blood levels of this medication. Tell your doctor if you smoke or have recently stopped smoking. Your dose of medication may need to be adjusted.
Caffeine and alcohol can increase the side effects of this medication. Avoid drinking large amounts of beverages containing alcohol or caffeine (e.g., coffee, tea, colas), or eating large amounts of chocolate.
Certain diets (high protein/low carbohydrate or high carbohydrate/low protein) may change the effect of theophylline. Tell your doctor if you are following a dietary plan or eat beef every day. The dose of your medicine may need to be adjusted.
Theophylline is very similar to aminophylline and oxtriphylline. Do not take medications containing aminophylline or oxtriphylline while using theophylline.
This medication may interfere with certain laboratory tests (e.g., blood sugar, cholesterol, uric acid, dipyridamole-thallium imaging tests), possibly causing false test results. Make sure laboratory personnel and all your doctors know you use this drug.
Laboratory tests for drug blood levels may be affected by other drugs/foods, possibly causing false test results. Tell all your doctors and laboratory personnel if you use any of the following products: caffeine, theobromine, chocolate, furosemide, sulfathiazole, phenylbutazone, probenecid, acetaminophen, cefazolin, cephalothin.
This document does not contain all possible interactions. Therefore, before using this product, tell your doctor or pharmacist of all the products you use. Keep a list of all your medications with you, and share the list with your doctor and pharmacist.