Besides the desired beneficial effects that glucocorticosteroid have on the immune system, many other undesired adverse effects are induced. Glucocorticoid receptors are widespread over all kinds of tissues and organs. The effect GCs have on increased risk for infections can easily be explained by their immune suppressive actions. As can be deduced from their physiological effect, glucocorticosteroid supplement will result in exaggeration of these effects. Decreased uptake and utilisation of glucose combined with increased gluconeogenesis will result in hyperglycemia (and eventually diabetes). There will be redistribution of fat and obesity as seen in Cushings syndrome (too much glucocorticosteroids).
In muscles GCs cause myopathy and in bone osteoporosis because of the increased osteoclast and decreased osteoblast activity. Hypertension and edema occur because GCs reduce vasodilation and retain fluids. Patients own glucocorticoid production will decrease because of the negative feedback effect of GC supplement. High GC levels can have effect on the brain (comparable with long-term stress effects) and cause neuropsychiatric diseases. Additional adverse effects are glaucoma in the eye and thinning of the skin when used topically.An example of how to dose glucocorticosteroids with good effects and least as possible adverse effects is shown in steroids and therapy.