Symbicort (budesonide and formoterol fumarate dihydrate) is a combination of a steroid and a long-acting bronchodilator used to prevent bronchospasm in people with (asthma) or (chronic obstructive pulmonary disease )(COPD). most Common side effects of Symbicort include: • throat irritation Rinse the mouth with water and spit the water out after each dose of SYMBICORT. (Do not swallow the water). This will help to lessen the chance of getting a fungus infection (thrush) in the mouth and throat. ع