This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Opioids and Alcohols, Subject name: Pharmacology
Morphine is used in the treatment of:- 
Select and explain. 
A. Hypeension, B. Cardiac arrhythmias, C. Acute left ventricular failure, D. A-V block
C: Acute left ventricular failure
Answer: C: Acute left ventricular failure 
Explanation: These are used as analgesic agents. Visceral, dull and constant pain is relieved more effectively than inflammatory pain. Opioids are however contraindicated in biliary colic. Morphine (i.v.) is useful in myocardial infarction as well as in pulmonary edema due to acute left ventricular failure.