Drug Interaction Report

Using dyphylline together with formoterol may increase cardiovascular side effects such as heart palpitations, increased heart and pulse rates, and blood pressure elevations. Combining these medications may also increase the risk of developing hypokalemia, or low blood potassium. Although the hypokalemia associated with these drugs is generally mild and does not cause problems, severe cases can occasionally lead to muscle weakness, paralysis, breathing and swallowing difficulties (due to muscle paralysis), and irregular heart rhythm. Side effects may be more likely if you are receiving formoterol or similar medications in the nebulized, oral, or injectable form. In addition, these medications given orally or by injection may sometimes reduce the blood levels and effects of dyphylline. You may need a dose adjustment or more frequent monitoring by your doctor to safely use both medications. Let your doctor know if your breathing worsens or you experience nausea, vomiting, constipation, abdominal cramping, confusion, dizziness, lightheadedness, fainting, muscle weakness, muscle cramps, numbness, tingling, rapid heartbeat, chest pain, and/or swelling in the legs or feet, as these may be symptoms of hypokalemia. It is important to tell your doctor about all other medications you use, including vitamins and herbs. Do not stop using any medications without first talking to your doctor.