What is the main adverse reaction associated with high doses of benzimidazoles?

Benzimidazoles, a class of anthelmintic agents, are primarily used to treat infections caused by various helminths. At high doses, one of the significant adverse reactions associated with benzimidazoles is bone marrow suppression. This can lead to a decrease in blood cell production, resulting in conditions such as anemia, leukopenia, or thrombocytopenia. The mechanism behind this adverse effect is related to the drug's interference with the synthesis of microtubules, which are crucial for cellular division, including that of bone marrow cells.

While other adverse reactions such as gastrointestinal disturbances (like nausea and vomiting) or skin reactions can occur, they are generally not as serious or as frequently associated with high doses of benzimidazoles as bone marrow suppression. This specific adverse reaction underscores the need for careful monitoring when administering these medications, particularly at higher doses, to avoid potentially severe hematological consequences.