Which local anesthetic is inappropriately paired with its clinical application because of toxicity concerns?

Which local anesthetic is inappropriately paired with its clinical application because of toxicity concerns?

• A. Tetracaine, topical anesthesia
• B. Bupivacaine, intravenous anesthesia
• C. Prilocaine, infiltrative anesthesia
• D. Chloroprocaine, epidural anesthesia

Answer: (B)

Toxicity risk rises with local anesthetics that are highly lipid-soluble and potent, because they reach high plasma concentrations quickly and strongly depress excitable tissues, especially the heart. Bupivacaine is exceptionally cardiotoxic due to its high lipid solubility and strong, long-lasting blockade of cardiac sodium channels. That makes intravascular or intravenous regional administration particularly dangerous because even small amounts entering the circulation can cause severe arrhythmias or cardiac arrest. Because of this, using bupivacaine for intravenous regional anesthesia (a Bier block) is avoided; safer alternatives like lidocaine or prilocaine are preferred for IV use. The other pairings align with common practice. Tetracaine, though long-acting, is routinely used for topical anesthesia of mucosal surfaces and the eye, where controlled, localized absorption limits systemic toxicity. Prilocaine is widely used for infiltrative anesthesia in minor procedures, with attention to dose to avoid methemoglobinemia. Chloroprocaine is an ultra-short-acting ester suitable for epidural anesthesia in appropriate settings, especially when rapid recovery is desired.

Toxicity risk rises with local anesthetics that are highly lipid-soluble and potent, because they reach high plasma concentrations quickly and strongly depress excitable tissues, especially the heart. Bupivacaine is exceptionally cardiotoxic due to its high lipid solubility and strong, long-lasting blockade of cardiac sodium channels. That makes intravascular or intravenous regional administration particularly dangerous because even small amounts entering the circulation can cause severe arrhythmias or cardiac arrest. Because of this, using bupivacaine for intravenous regional anesthesia (a Bier block) is avoided; safer alternatives like lidocaine or prilocaine are preferred for IV use.

The other pairings align with common practice. Tetracaine, though long-acting, is routinely used for topical anesthesia of mucosal surfaces and the eye, where controlled, localized absorption limits systemic toxicity. Prilocaine is widely used for infiltrative anesthesia in minor procedures, with attention to dose to avoid methemoglobinemia. Chloroprocaine is an ultra-short-acting ester suitable for epidural anesthesia in appropriate settings, especially when rapid recovery is desired.