G6PD is an enzyme that helps protect red blood cells (RBCs) from destruction after they are exposed to certain "triggers" (certain medicines and some foods). When RBCs are destroyed, a temporary condition known as "anemia" occurs because of the low RBC amounts counts in the blood. Some people do not have enough G6PD to protect their RBCs and this condition is known as G6PD deficiency. G6PD deficiency is caused by inherited variations in the G6PD gene; because this is a genetic condition, G6PD deficiency is a life-long condition.
More than one hundred such variations exist in the G6PD gene. These variations can lead to the production of a G6PD enzyme with little or no function. A system designed to classify patients into 2 categories based on the ability of their G6PD to prevent damage is used by clinicians to help guide drug therapy decisions.
Priority G6PD phenotype
- G6PD deficiency – These patients have little or no working G6PD. About 400 million people have deficient G6PD enzyme activity. This deficiency is more common in people of African, Mediterranean or Southeast Asian descent. Without enough G6PD, certain medications can cause RBCs to break down and lose their ability to carry oxygen (a condition known as "hemolytic anemia"). Medications that need to be avoided in patients with G6PD deficiency include:
|Anti-infective medications||Dapsone, mafenide, nitrofurantoin, quinine, sulfacetamide, sulfadiazine, sulfanilamide, sulfamethoxazole (note: sulfamethoxazole is an ingredient in Septra® or Bactrim®)|
|Other miscellaneous medications||Methylene blue, pegloticase, phenazopyridine, rasburicase|
Most medicines don't need to be adjusted based on the following phenotype:
- Normal G6PD activity – These patients have normal G6PD activity. No particular medicines or food should be avoided based on G6PD status alone.
More information for patients
- "Do you know..." info sheet: G6PD deficiency
- "Do you know…" info sheet: G6PD deficiency (in Spanish)
More information for healthcare professionals
- Visit https://cpicpgx.org.
Legal Disclaimer: This page is intended to provide implementers with guidance on establishing a clinical pharmacogenetic program at their institution. Information contained on this page is for information and educational purposes only. Although reasonable efforts have been made to ensure that the information provided on this page is current, complete and, where appropriate, based on scientific evidence, St. Jude Children's Research Hospital makes no assurances as to whether the provided information will at all times be current or complete. St. Jude Children's Research Hospital, in offering this document, is not providing medical advice or offering a consultative opinion, and is not establishing a treatment relationship with any given individual. You, therefore, should not substitute information contained herein for your own professional judgment, nor should you rely on information provided herein in rendering a diagnosis or choosing a course of treatment for a particular individual.