What is Primaquine and How Does it Work?

Primaquine is an antimalarial drug that is commonly used to treat malaria caused by Plasmodium species. It works by generating oxidative stress in the malarial parasite, damaging its cellular components and preventing its replication. However, this same mechanism of action can be harmful to the human host under certain conditions, especially for individuals with specific enzyme deficiencies.

What is Glucose-6-Phosphate Dehydrogenase (G6PD) Deficiency?

Glucose-6-phosphate dehydrogenase (G6PD) is an important enzyme in the body’s red blood cells. It is crucial for maintaining the balance of oxidative stress in the cells. G6PD helps produce NADPH, which is essential for protecting red blood cells from oxidative damage.

When there is a deficiency in G6PD, red blood cells are more vulnerable to oxidative stress. Without sufficient G6PD activity, the cells cannot produce enough NADPH, and they are more likely to undergo hemolysis (destruction of red blood cells) when exposed to oxidative agents such as primaquine.

Why is Primaquine Dangerous for People with G6PD Deficiency?

Primaquine generates oxidative stress as part of its mechanism to kill the malaria parasite. However, in individuals with G6PD deficiency, their red blood cells are less equipped to handle this oxidative stress. As a result:

• Red blood cells are more likely to break down, leading to hemolysis.

• This can result in hemolytic anemia, a serious condition where the body does not have enough red blood cells to carry oxygen.

Therefore, individuals with G6PD deficiency are at a higher risk of experiencing severe side effects when taking primaquine, including jaundice, fatigue, and anemia.

Correct Answer: Option 2 – Glucose 6-phosphate dehydrogenase

Primaquine is unsuitable for individuals with glucose-6-phosphate dehydrogenase (G6PD) deficiency because the lack of G6PD activity makes their red blood cells more susceptible to oxidative stress, leading to hemolysis and other complications.

Conclusion

Primaquine is an effective antimalarial drug, but it should be avoided in individuals with G6PD deficiency. This enzyme deficiency impairs the ability of red blood cells to cope with oxidative stress, making them more prone to damage by drugs like primaquine. It is essential for healthcare providers to screen for G6PD deficiency before prescribing drugs like primaquine to avoid dangerous side effects such as hemolysis.