Ask your doctor or pharmacist before using any other medicine, including over-the-counter medicines, vitamins, and herbal products.
Make sure your doctor knows if you are using medicines for breathing problems such as theophylline (Slo-Bid?, Theo-Dur®).
Tell your doctor if you use medicines, foods, or drinks that contain caffeine. You may need to avoid all caffeine for several hours before your test. Carefully follow your doctor's instructions about eating and drinking before your test.
Make sure your doctor knows if you are pregnant or breastfeeding, or if you have asthma or myasthenia gravis. Tell your doctor if you have a history of chest pain (angina), heart disease, or heart rhythm problems.