Its mechanism of action is believed to be based on its inhibition of the enzyme ribonucleotide reductase by scavenging tyrosyl free radicals as they are involved in the reduction NDPs.
Chronic myelogenous leukemia
Sickle-cell disease (breaks down cells that are prone to sickle, as well as increasing fetal hemoglobin content)
AIDS as an adjunct to ddI in combination antiretroviral therapies
Biochemical research as a DNA replication inhibitor that causes ribonucleotide depletion and results in DNA double strand breaks near replication forks (see DNA repair)
Moderate to severe psoriasis (slows down the rapid division of skin cells)
500 milligrams once or twice a day, or more if pancytopenia does not develop.
Reported side-effects are: drowsiness, nausea, vomiting and diarrhea, constipation, mucositis, anorexia, stomatitis, bone marrow toxicity (which may take 7-21 days to recover after the drug has been discontinued), alopecia (hair loss), skin changes, abnormal liver enzymes, creatinine and blood urea nitrogen.
Category D - investigational or post-marketing data show risk to the fetus. However, potential benefits may outweigh the potential risk. Generally this rating is reserved for drugs with no safer alternatives.
Contraindications are: severe anemia, bone marrow depression or neutropenia.