Moderate to Severe Psoriasis: "Off-label" Systemic Medications
There are additional systemic medications that are not approved by the FDA for treating psoriasis and psoriatic arthritis. However, some doctors prescribe them off-label—a common and accepted medical practice.
Hydrea (hydroxyurea) is an oral cancer medication found to be effective for psoriasis in the late 1960s. Hydrea can produce significant improvement in stable plaque psoriasis, but it also has potentially dangerous side effect, including bone marrow toxicity. Long-term use has been associated with skin cancer.
Isotretinoin is an oral retinoid approved as a treatment for severe cystic acne. The most common side effects of isotretinoin are eye and lip dryness, and nosebleeds. Bone spurs and hair loss occur to a lesser degree.
Isotretinoin has the potential for severe birth defects if a woman becomes pregnant while the drug is still in her system. A woman on isotretinoin should use reliable birth control one month before treatment, during treatment and for at least one month afterward.
Mycophenolate mofetil is used for the prevention of organ transplant rejection, as well as in the treatment of several inflammatory or autoimmune skin diseases. It has been used in combination with cyclosporine. Because it is an immunosuppressive agent, people with compromised immune systems should not take it.
Sulfasalazine is a combination anti-inflammatory and antibiotic commonly used for treating psoriatic arthritis. Many people cannot tolerate sulfasalazine because of allergy to sulfa, or because of side effect, including nausea, vomiting and loss of appetite.
6-thioguanine is an oral medication approved for treating certain types of leukemia. 6-Thioguanine has been reported to be effective for psoriasis, including treatment of pustular psoriasis. 6-Thioguanine must be used under close supervision due to the potential side effects associated with suppression of the bone marrow.