This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Anesthesia, Subject name: Pharmacology
[{'content': 'Anesthetic agent with vasoconstrictor is contraindicated in \nSelect and explain. \nA. Digital block, B. Spinal block, C. Epidural block, D. Regional anesthesia', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Refer Katzung 11/e p446 Vasoconstrictors are contraindicated if LAs are used for organs with end aeries like tips of fingers, toes, nose, pinnacle, and penis due to risk of ischemia and necrosis', 'role': 'assistant'}]