What is the risk associated with injecting local anesthetic into a patient's blood vessel?

Injecting local anesthetic into a patient's blood vessel significantly increases the risk of overdose because it allows the medication to enter the systemic circulation immediately. When local anesthetics are mistakenly injected into a blood vessel, rather than the intended tissue, higher concentrations of the drug can rapidly reach the heart and central nervous system. This can lead to cardiovascular and neurological toxicities, such as cardiac arrhythmias, hypotension, seizures, or even respiratory arrest, depending on the specific anesthetic used and the dose administered.

The risk of overdose is particularly concerning with certain local anesthetics that have higher systemic absorption rates or with larger volumes being injected. This highlights the importance of ensuring proper technique during administration, including aspiration to check for blood return, which can indicate the presence of a blood vessel. Consequently, understanding the pharmacological properties of local anesthetics and the implications of incorrect administration is vital in minimizing potential complications.