An attempt was made to evaluate the therapeutic effectiveness and toxicity of hydroxyurea administered in intermittent courses over a period of 18 months for the treatment of 60 patients with severe or incapacitating psoriasis. Hydroxyurea produced satisfactory results (good to excellent) in 63% of the patients in the first six weeks of therapy and remained similarly effective in 50% of the patients given intermittent therapy over the 18-month study period. The eruption relapses almost always upon the discontinuance of the drug with the development of resistance to further therapy in 13% of patients. Fifteen percent of the patients experienced severe enough drug toxicity to necessitate its discontinuance. Hydroxyurea should be reserved for patients who have extensive psoriasis and need clinical response because of special circumstances.
Moschella SL, Greenwald MA. Psoriasis With HydroxyureaAn 18-Month Study of 60 Patients. Arch Dermatol. 1973;107(3):363-368. doi:10.1001/archderm.1973.01620180017005