Final answer:
Nitrofurantoin is contraindicated in G6PD patients due to the risk of oxidative stress causing hemolytic anemia. Sulfonamides and chloramphenicol are also contraindicated for the same reason.
Step-by-step explanation:
Nitrofurantoin is contraindicated in patients with glucose-6-phosphate dehydrogenase (G6PD) deficiency because it can induce oxidative stress in red blood cells (RBCs), leading to hemolysis. G6PD is an enzyme that is crucial for protecting RBCs from oxidative damage. Without enough G6PD, RBCs are more vulnerable to being destroyed by certain drugs that induce oxidative stress.
Other drugs contraindicated for G6PD-deficient patients include sulfonamides, chloramphenicol, and primaquine. These drugs can also lead to oxidative damage of RBCs, resulting in hemolytic anemia. Some can trigger the same damaging effect on the red blood cells in patients with G6PD deficiency because of the increased oxidative stress or interference with the pathways that help in maintaining red blood cell integrity.