Acto Pred 500mg Injection is a steroid. It is used to treat a wide variety of medical conditions such as severe allergic reactions, allergic conditions, asthma, rheumatic disorder, skin and eye disorders, and nephrotic syndrome. It suppresses the immune system and provides relief from inflammation. Acto Pred 500mg Injection is generally given by a doctor or a nurse. Do not self-administered the injection at home. To get the most benefit, get this injection at evenly spaced times and continue using it until your prescription is finished, even if your symptoms disappear after a few days. The most common side effects of this medicine include mood changes, upset stomach, and pain, swelling, or redness at the site of injection. You could ask your doctor about ways of preventing or reducing these effects. You should stop taking it straight away if you have any signs of an allergic reaction. Signs of this include rash, swelling of the lips, throat, or face, swallowing or breathing problems, feeling dizzy or faint, and nausea.