Haematology and ART

The most commonly observed haematological adverse drug reaction is macrocytic anaemia and neutropenia and is related to zidovudine intake, being an effect of the drug’s direct suppressive effect on bone marrow. This adverse effect is quite rare, but can be life threatening. It can occur within weeks or months from drug initiation and the risk of it is higher in patients with advanced HIV disease and with co-administration of other bone marrow suppressants (e.g. TMP-SMX, pyrimethamine, interferon, ribavirin, ganciclovir) (1,2).

Patients taking zidovudine and stavudine often develop clinically insignificant macrocytosis (increase in the mean red cell volume - MCV) that occurs usually four months after treatment initiation. Macrocytosis is observed in 80% of patients taking zidovudine and because of that it can be used as a surrogate marker of patient adherence to treatment (3-5).

1. Blood 1991;77:2109
2. Current haemoglobin levels are more predictive of disease progression than haemoglobin measured at baseline in patients receiving antiretroviral treatment for HIV-1 infection. JD Kowalska, A Mocroft, A Blaxhult, R Colebunders, J van Lunzen, D Podlekareva, A-BE Hansen, L Machala, I Yust and T Benfield for the EuroSIDA Study Group.
AIDS Res Hum Ret. 2007; 23 (10): 1183-1188
3. Volberding PA, Lagakos SW, Koch MA, et al. Zidovudine in asymptomatic human immunodeciency virus infection. A controlled trial in persons with fewer than 500 CD4-positive cells per cubic millimetre.
N Engl J Med 1990;322:941-9
4. Steele RH, Keogh GL, Quin J, Fernando SL, Stojkova V. Mean cell volume (MCV) changes in HIV-positive patients taking nucleoside reverse transcriptase inhibitors (NRTIs): a surrogate marker for adherence.
Int J STD AIDS 2002;13:748-754
5. Romanelli F. Macrocytosis as an indicator of medication (zidovudine) adherence in patients with HIV infection.
AIDS Patient Care STDs 2002;16:405-411