PRECAUTIONS: Before using theophylline, tell your doctor or pharmacist if you are allergic to it; or to theobromine or caffeine; or if you have any other allergies.Before using this medication, tell your doctor or pharmacist your medical history, especially of: a certain breathing disorder (cystic fibrosis), glaucoma, diabetes, heart problems (e.g., congestive heart failure, irregular heartbeat), high blood pressure, kidney disease, liver disease (e.g., cirrhosis), seizures, stomach/intestinal ulcer, thyroid disease.This drug may make you dizzy. Do not drive, use machinery, or do any activity that requires alertness until you are sure you can perform such activities safely. Limit alcoholic beverages.If you develop a fever/flu-like symptoms while taking this medication, tell your doctor promptly. The dose of your medicine may need to be adjusted.Before having surgery, tell your doctor or dentist that you are using this medication.Caution is advised when using this drug in the elderly because they may be more sensitive to its effects. Careful monitoring of side effects and drug blood levels is recommended.Caution is advised when using this drug in children because they may be more sensitive to its effects. Careful monitoring of side effects, drug blood levels, and dose adjustment is recommended.During pregnancy, this medication should be used only when clearly needed. Discuss the risks and benefits with your doctor. Changes in your body during the last 3 months of pregnancy may affect the amount of this drug in your blood. Your doctor should carefully monitor the amount of drug in your blood, as well as any side effects, so that your dose may be changed if needed.This drug passes into breast milk and may have undesirable effects on a nursing infant (e.g., irritability). Consult your doctor before breast-feeding.

DRUG INTERACTIONS: 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.This drug should not be used with the following medication because very serious interactions may occur: febuxostat.If you are currently using the medication listed above, tell your doctor or pharmacist before starting theophylline.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, macrolide antibiotics (e.g., erythromycin, clarithromycin), isoproterenol, lithium, methotrexate, moricizine, pentoxifylline, certain quinolones (e.g., ciprofloxacin, enoxacin), 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.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.

Report Problems to the Food and Drug Administration You are encouraged to report negative side effects of prescription drugs to the FDA. Visit the FDA MedWatch website or call 1-800-FDA-1088. Need help identifying pills and medications? Use the pill identifier tool on RxList.