Bromethalin is described as an alternative rodenticide to warfarin. Its primary mechanism is which?

• A. Inhibition of vitamin K recycling
• B. Uncoupling oxidative phosphorylation
• C. Glycine receptor antagonism
• D. Acetylcholinesterase inhibition

Answer: (B)

Bromethalin works by uncoupling oxidative phosphorylation in mitochondria, particularly in brain cells. By dissipating the proton gradient across the inner mitochondrial membrane, it stops ATP production even though electron transport continues. The resulting ATP depletion impairs energy-dependent processes, including the Na+/K+-ATPase pump, leading to cellular swelling and cerebral edema. The central nervous system is especially sensitive, so this energy failure manifests as tremors, hyperexcitability, and seizures. This mechanism is different from anticoagulant rodenticides that inhibit vitamin K recycling, and it’s not a glycine receptor antagonist or acetylcholinesterase inhibitor, which would cause other toxic effects. Bromethalin’s hallmark is mitochondrial uncoupling and neural energy failure.