It is a corticosteroid drug with predominantly glucocorticoid and low mineralocorticoid activity, making it useful for the treatment of a wide range of inflammatory and auto-immune conditions such as asthma, rheumatoid arthritis, ulcerative colitis and Crohn's disease, multiple sclerosis, cluster headaches and systemic lupus erythematosus. It can also be used as an immunosuppressive drug for organ transplants and in cases of adrenal insufficiency (Addison's). Prednisolone acetate ophthalmic suspension is an adrenocortical steroid product prepared as a sterile ophthalmic suspension, used to reduce swelling, redness, itching, and allergic reactions affecting the eye. Corticosteroids inhibit the inflammatory response to a variety of inciting agents and probably delay or slow healing. They inhibit the edema, fibrin deposition, capillary dilation, leukocyte migration, capillary proliferation, fibroblast proliferation, deposition of collagen, and scar formation associated with inflammation. There is no generally-accepted explanation for the mechanism of action of ocular corticosteroids. However, corticosteroids are thought to act by the induction of phospholipase A2 inhibitory proteins, collectively called lipocortins. It is postulated that these proteins control the biosynthesis of potent mediators of inflammation such as prostaglandins and leukotrienes by inhibiting the release of their common precursor arachidonic acid. Arachidonic acid is released from membrane phospholipids by phospholipase A2. Corticosteriods are capable of producing a rise in intraocular pressure.