All medication has side effects which may vary from serious to mild. It is strongly recommended to stop using COMBIVENT and get immediate emergency medical help if you have any of these signs of an allergic reaction including hives, difficulty breathing and swelling of your face, lips, tongue, or throat. Stop using COMBIVENT and contact your healthcare professional immediately if you experience any of the noted serious side effects: bronchospasm (wheezing, chest tightness, trouble breathing), chest pain and fast, pounding, or uneven heart beats, swelling of your ankles or feet, vision problems, eye pain, or seeing halos around lights, pain or burning with urination, increased blood pressure, severe headache, blurred vision, trouble concentrating, chest pain, numbness, seizure hoarse voice, sore throat, cough, runny or stuffy nose, constipation or diarrhea, nausea or upset stomach, headache, leg cramps