Get emergency medical help if you have signs of an allergic reaction: hives; difficult breathing; swelling of your face, lips, tongue, or throat.
Call your doctor at once if you have:
shortness of breath (even with mild exertion), swelling, rapid weight gain;
bruising, thinning skin, or any wound that will not heal;
blurred vision, tunnel vision, eye pain, or seeing halos around lights;
severe depression, changes in personality, unusual thoughts or behavior;
new or unusual pain in an arm or leg or in your back;
bloody or tarry stools, coughing up blood or vomit that looks like coffee grounds;
seizure (convulsions); or
low potassium--leg cramps, constipation, irregular heartbeats, fluttering in your chest, increased thirst or urination, numbness or tingling.
Steroids can affect growth in children. Tell your doctor if your child is not growing at a normal rate while using  Medrol.
Common side effects may include:
fluid retention (swelling in your hands or ankles);
dizziness, spinning sensation;
changes in your menstrual periods;
headache;
mild muscle pain or weakness; or
stomach discomfort, bloating.
This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.
 Medrol side effects (more detail)
