Built-in Blocker: Drug and antidote in the same molecule

In cases of serious side effects or overdoses of medications, it can be vital to have a fast-acting antidote on hand. This is especially true of drugs that inhibit blood clotting, which are used to prevent and treat thromboses and embolisms, to treat heart attacks, and, in higher doses, in dialysis and in heart surgeries involving a heart-lung machine. Overdoses can lead to life-threatening hemorrhages.