Certain drugs such as troleandomycin (TAO), erythromycin ( Ery-Tab , EryPed 200), and clarithromycin ( Biaxin ) and ketoconazole ( Nizoral ) can reduce the ability of the liver to metabolize (breakdown) corticosteroids and this may lead to an increase in the levels and side effects of corticosteroids in the body. On the other hand, phenobarbital, ephedrine , phenytoin ( Dilantin ), and rifampin ( Rifadin , Rimactane ) may reduce the blood levels of corticosteroids by increasing the breakdown of corticosteroids by the liver. This may necessitate an increase of corticosteroid dose when they are used in combination with these drugs.
Another common fear about corticosteroids is that they will cause growth suppression in children. To date, many studies have been done that prove that corticosteroids do not stunt a child's growth. Six years of ongoing studies in children and adolescents who used inhaled corticosteroids show that the speed of growth may be slowed by about 1 cm. over one year in children. However, these children catch up and do attain their full adult height. In some studies, these children grew even taller than their siblings. Interestingly, poorly controlled asthma can actually contribute to growth suppression.