Hydroxyurea (brand name: Hydrea) has been
on the market as an anti-cancer drug for over 30 years.
Initially, it was used to treat some types of leukemia, as well
as ovarian cancer and sickle cell anemia. However, it has
recently been shown to have powerful anti-retroviral properties.
The results of initial testing in HIV infected patients have been
- Administration: Hydroxyurea is taken
once daily by mouth, on an empty stomach.
- Indications: Hydroxyurea is prescribed
in some instances for leukemia, ovarian cancer, sickle cell anemia,
- Side Effects: Skin rash, fever, chills,
sore throat, mouth sores, bruising and bleeding, back pain.
- Contraindications: Pregnancy, anemia,
infections (particuarly primary VZV infection), kidney disease.
- Mechanism: Hydroxyurea alters the
cellular enzyme ribonucleotide reductase which normally facilitates
the formation of dNTP's. Without the presence of this enzyme,
HIV is unable to reverse transcribe its RNA to DNA. Thus,
Hydroxyurea reduces the viral load in some cases to levels which
are undetectable. There is some evidence that this effect
may persist for the long term, even when anti-viral therapy is
halted. Additionally, Hydroxyurea penetrates the brain
and lymph tissues, which may make it more effective than other
anti-HIV drugs at preventing or treating HIV infection of the
While this data is very exciting, it is not
yet clear whether the anti-viral effects observed in vitro will
be as profound in patients. Most of the clinical studies
conducted thus far had very small sample sizes and involved patients
with low viral loads initially. Finally, as Hydroxyurea
suppresses T cell maturation, it is unlikely that this will be
an effective treatment of patients with end-stage HIV infection.
For information that is slightly dated (1998-1999)
but very thorough, see:
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