Stelara is an immune system suppressant that alleviates inflammation caused by a chemical, according to Drugs.com. The drug is primarily used to treat plaque psoriasis and psoriatic arthritis.
Stelara is administered by injection under the skin with an initial 45-milligram dose, followed by another dose four weeks later, notes Drugs.com. Maintenance doses of 45 milligrams are given every 12 weeks thereafter.
Plaque psoriasis is characterized by patches of inflamed, scaling and red skin, which is caused by the rapid overproduction of skin cells due to an immune system disorder, notes WebMD. Psoriatic arthritis couples the symptoms of psoriasis with joint pain, stiffness and inflammation.