G6PD Deficiency and Adverse Drug Reactions

Glucose-6-phosphate dehydrogenase (G6PD) deficiency, also known as favism, is the most common enzyme deficiency in the world, caused by the presence of mutations in the G6PD gene. It is characterized by episodes of hemolysis that can be triggered by certain factors, including many drugs.

Glucose-6-phosphate dehydrogenase (G6PD) deficiency is a metabolic disorder in which the destruction of red blood cells (hemolysis) occurs when a person is exposed to certain triggers such as drugs, foods (such as fava beans), or stressful situations or infection.

It is an X-linked inherited disease, so it is more common in men, who may also have a more severe phenotype. It is important to note that heterozygous women may show some symptoms due to the X chromosome inactivation process.

In general, the disease does not produce symptoms until the body is exposed to the triggers.

The most common symptoms of the hemolytic episode are:

• Dark-colored urine
• Fever
• Abdominal pain
• Fatigue
• Paleness
• Rapid heart rate
• Jaundice

Regarding the treatment of G6PD deficiency, there is no specific treatment for the disease itself, but episodes of hemolysis can be effectively managed by discontinuing the triggering drug or food. In more severe, although rare, cases, a blood transfusion may be necessary.

Therefore, it is important that carriers of some variant of predisposition to G6PD deficiency are aware of the triggering agents of hemolysis episodes and avoid their consumption.

Regulatory agencies around the world advise against the use of certain medications in people with G6PD deficiency. It is important to note that exposure to certain drugs can trigger episodes of hemolysis in people with G6PD deficiency. The CPIC (Clinical Pharmacogenetics Implementation Consortium) guideline recommends avoiding the consumption of the following medications and compounds due to the high risk of hemolysis:

• Dapsone: antibiotic used to treat leprosy and some skin infections.
• Methylene blue
• Pegloticase
• Rasburicase
• Tafenoquine
• Primaquine
• Nitrofurantoin
• Toluidine blue

There are other compounds that should be used with caution, as they may increase the risk of hemolysis in people with G6PD deficiency. In addition to the above drugs, there are many others in which special caution should be taken due to the increased risk of hemolysis in people carrying G6PD deficiency. These include: sulfoxones, ascorbic acid, bupivacaine, ciprofloxacin, diethylamine, dimenhydrinate, dimercaprol, dorzolamide, enoxacin, furalidone, gliclazide, glimepiride, hydroxychloroquine, nitric oxide, acetylsalicylic acid, or sulfamethoxazole, among others.

It is essential that patients with G6PD deficiency are aware of the risks associated with certain medications, especially those used to treat malaria, such as primaquine and tafenoquine. These medications are specifically contraindicated in people with G6PD deficiency due to their ability to trigger hemolysis and endanger the patient's health. Ensuring that the medications used do not interfere with red blood cell function is essential to avoid serious complications.