What is a common side effect of benzocaine use related to local anesthetics?

Benzocaine, a local anesthetic commonly used for topical applications, can lead to a side effect known as methemoglobinemia. This condition occurs when the iron in hemoglobin is oxidized to the ferric state, which impairs the blood’s ability to carry oxygen. In patients with methemoglobinemia, blood can take on a characteristic chocolate-brown color, and symptoms may include cyanosis, fatigue, and, in severe cases, respiratory distress.

The risk of methemoglobinemia is particularly associated with benzocaine due to its ability to be absorbed systemically when applied in high concentrations or to large surface areas. This makes awareness of the dosage and area of application crucial in preventing this potentially serious side effect. Other local anesthetics, such as lidocaine, do not share this risk in the same manner, highlighting the unique toxicity profile of benzocaine.

Understanding this complication is essential for clinicians to ensure patient safety and proper management of local anesthesia techniques in oral and maxillofacial surgery.