What is the toxic dose of bupivacaine (Marcaine) with epinephrine?

• A. 225 mg
• B. 175 mg
• C. 250 mg
• D. 200 mg

Answer: (A)

Bupivacaine with epinephrine allows a higher maximum safe dose because epinephrine constricts blood vessels, slowing how quickly the drug enters the bloodstream and reducing peak plasma levels. The commonly cited maximum recommended dose is 3 mg per kilogram of body weight, and in an average adult this translates to about 225 mg. This 225 mg figure serves as a practical toxic-dose threshold: staying at or below it minimizes the risk of systemic toxicity, while exceeding it raises the danger of LAST (local anesthetic systemic toxicity), which can affect the brain and heart.

In real clinical terms, the exact toxic dose varies with weight and other factors (age, cardiovascular status, comorbidities), but the 225 mg cap for an average adult is a widely used reference. The other amounts fall short of this practical limit or exceed it for typical adults, which is why 225 mg is the best anchor for assessing toxic-dose risk with epinephrine present.