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