Letter to the Editor
I thank Andrew Somogyi and Elizabeth Phillips for their article on the role of pharmacogenomics in drug therapy.1 However, I am surprised and concerned that their discussion is limited to recently identified genes and will mislead the casual reader about the importance of genetic testing in daily practice.
For example, glucose 6-phosphate dehydrogenase (G6PD) deficiency has been acknowledged as ‘the most common enzyme deficiency in the world’.2 Its role in acute drug-induced haemolytic anaemia has been known for over half a century.3 Medicines including primaquine and rasburicase are definite triggers for drug-induced haemolytic anaemia in patients with G6PD deficiency, but other commonly used drugs can also possibly cause it, including some sulphur-containing antibiotics, quinolones, high doses of aspirin and paracetamol.
Genetic testing also enables early diagnosis of other haemoglobinopathies such as sickle cell anaemia and beta-thalassemia. Many patients with these are also sensitive to drug-induced haemolytic anaemia via oxidative stress from medicines similar to the list above.4
Testing for G6PD deficiency is rebateable on the Medicare Benefits Schedule, but genetic testing for haemoglobinopathies are often not. More importantly, most direct-to-consumer genetic testing kits would include these conditions for investigation. In our increasingly multicultural society, awareness of these genetic conditions is ever so relevant to those of Asian, Mediterranean and African ethnicities.
Many recent review articles continue to list G6PD deficiency as an important exemplar when discussing advances in pharmacogenomics.2,3,5,6 I fear that its conspicuous absence in this Australian Prescriber article will only reinforce the mistaken triviality of this common condition in the psyche of prescribing doctors.
- Somogyi AA, Phillips E. Genomic testing as a tool to optimise drug therapy. Aust Prescr 2017;40:101-4.
- Alfirevic A, Pirmohamed M. Adverse drug reactions and pharmacogenomics: recent advances. Per Med 2008;5:11-23.
- Luzzatto L, Seneca E. G6PD deficiency: a classic example of pharmacogenetics with on-going clinical implications. Br J Haematol 2014;164:469-80.
- Fibach E, Rachmilewitz E. The role of oxidative stress in hemolytic anemia. Curr Mol Med 2008;8:609-19.
- Khan DA. Pharmacogenomics and adverse drug reactions: primetime and not ready for primetime tests. J Allergy Clin Immunol 2016;138:943-55.
- Collins SL, Carr DF, Pirmohamed M. Advances in the pharmacogenomics of adverse drug reactions. Drug Saf 2016;39:15-27.
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