Metabolism
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An adverse response to antimalarial medication -
Samuel
W is an African-American recruit to the army. He was given the antimalarial
drug primaquine, and suffered a delayed reaction with kidney pain, dark urine,
and low red blood cell counts that led to anaemia and weakness. Centrifugation
of a blood sample showed a low haematocrit, and the plasma was red coloured.
Similar acute haemolytic attacks have been observed, predominantly in men of Afro-Caribbean origin, in response to primaquine and a variety of other drugs, including dapsone, the antipyretic acetylphenylhydrazine, the antibacterial bactrim/septrim, sulphonamides and sulphones, whose only common feature is that they all undergo cyclic non-enzymic reactions in the presence of oxygen to produce hydrogen peroxide and a variety of oxygen radicals that can cause oxidative damage to membrane lipids, leading to haemolysis. Moderately severe infection can also precipitate a haemolytic crisis in susceptible people.