This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: G.I.T, Subject name: Pharmacology
Morphine should not be used in: 
Select and explain. 
A. Ischaemic pain, B. Biliary colic, C. Cancer pain, D. Post-operative pain
B: Biliary colic
Answer: B: Biliary colic 
Explanation: Ans. B. Biliary colicOpioids have potent analgesic effect via mu, kappa receptor. They are known to increase the intrabilliary pressure by constricting the smooth muscle. Therefore, they are contraindicated in biliary colic.