In regards to bone marrow suppression, chloramphenicol has two major etiological manifestations. The first mechanism of bone marrow suppression affects the formation of blood cells such as erythrocytes, and this can be reversible since it is an early sign of toxicity. The second form of bone marrow suppression is bone marrow aplasia, which is associated with being late into toxicity and cannot be reversed in some cases.
The two forms of chloramphenicol-induced bone marrow suppression are: one affecting blood cell production early on, potentially reversible; and another, bone marrow aplasia, which is late-stage and often irreversible.