Final answer:
The drug adjuvant being administered in this case is a vasoconstrictor, which prolongs the density and duration of the block and causes vasoconstriction at the injection site.
Step-by-step explanation:
The drug adjuvant being administered in this case is a vasoconstrictor.
A vasoconstrictor is a substance that constricts or narrows blood vessels, which can prolong the density and duration of the block when used in anesthesia. It also causes vasoconstriction at the injection site.
The standard dosage of the adjuvant is 5mcg/ml (1:200,000); however, it is recommended to use a dosage of 1:400,000 when using it for a block.