Methylprednisolone can cause short-term and long-term side effects. Side effects that can occur during or shortly after an infusion include blood-pressure changes, heart rate changes, irregular heart rate, electrolyte imbalances, elevated blood sugar, flushing of the skin, sweating, metallic taste, difficulty sleeping, mood or behavior changes, psychosis, seizures, increased susceptibility to infection, and anaphylaxis (serious allergic reaction).
If you need to take IV methylprednisolone or oral prednisone on an ongoing basis, the long-term side effects of corticosteroids include (but are not limited to) weight gain, acne, thinning of skin, stretch marks, elevated blood sugar, elevated cholesterol, peptic ulcers, cataracts, glaucoma, weight gain, decreased bone density, increased risk of osteonecrosis of the bone, growth suppression, muscle wasting, and increased susceptibility to infection.