an agent that interferes with viral replication by inhibiting the host cell enzyme ribonucleotide reductase, resulting in a reduction of the supply of the building blocks needed to make new DNA.

Indications: Has been shown to act synergistically with ddI and possibly d4T; not FDA-approved for management of HIV infection. Contraindications: Known hypersensitivity, significant bone marrow suppression, pregnancy. Dosage: 500 mg po bid. Toxicity: Bone marrow suppression, stomatitis, nausea, vomiting, rash; severe pancreatitis has been described infrequently. Pregnancy category D.

an anti-cancer drug that can boost ddI and d4T, but which is very rarely used now because of a high rate of side effects. A reduced dose of 300mg twice daily, may be more appropriate.

Hydroxyurea or hydroxycarbamide (the latter being the recommended International Non-Proprietary Name), (brand names include Hydrea®) is an antineoplastic drug used in hematological malignancies. It is also used as an antiretroviral agent (e.g., against HIV). Its mechanism of action is believed to be based on its inhibition of the enzyme ribonucleotide reductase by scavenging tyrosyl free radicals http://www.medscape.com/viewarticle/408266_8 as they are involved in the reduction NDPs http://www.ncbi.nlm.nih.gov/books/bv.fcgi?rid=stryer.section.3503.

One of the older anti-cancer drugs that is sometimes used in the treatment of psoriasis. When combined with acitretin, it can become more effective. Either in combination or alone, its use requires careful blood monitoring.

An anticancer drug that belongs to the family of drugs called antimetabolites.

A drug that has been shown to induce production of fetal hemoglobin. Fetal hemoglobin has a pair of gamma-globin molecules in place of the typical beta-globins of adult hemoglobin. Higher-than-normal levels of fetal hemoglobin can prevent sickling from occurring.