If used in a block, which is the only intermediate acting anesthetic without a vasoconstrictor?

If used in a block, which is the only intermediate acting anesthetic without a vasoconstrictor?

• A. Mepivicaine
• B. Prilocaine
• C. Articaine
• D. Lidocaine

Answer: (B)

Vasodilation level and inherent duration determine whether a local anesthetic can be used effectively for a block without a vasoconstrictor. Prilocaine has relatively low vasodilating tendency and yields a reliable intermediate duration even without added adrenaline, so it can be used for nerve blocks without a vasoconstrictor. The other agents generally rely more on a vasoconstrictor to achieve a comparable duration: lidocaine is a classic vasodilator that’s typically given with epinephrine to extend time and reduce bleeding; articaine’s strong vasodilatory effect necessitates a vasoconstrictor for a suitable block duration; mezpivacaine, while having less vasodilation than some, is not as consistently effective as prilocaine for blocks without vasoconstrictor.

Vasodilation level and inherent duration determine whether a local anesthetic can be used effectively for a block without a vasoconstrictor. Prilocaine has relatively low vasodilating tendency and yields a reliable intermediate duration even without added adrenaline, so it can be used for nerve blocks without a vasoconstrictor. The other agents generally rely more on a vasoconstrictor to achieve a comparable duration: lidocaine is a classic vasodilator that’s typically given with epinephrine to extend time and reduce bleeding; articaine’s strong vasodilatory effect necessitates a vasoconstrictor for a suitable block duration; mezpivacaine, while having less vasodilation than some, is not as consistently effective as prilocaine for blocks without vasoconstrictor.