This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: CHF, Angina Pectoris and Myocardial Infarction, Subject name: Pharmacology
Organic nitrates can lead to the development of tolerance when used chronically. Which of the following preparations is least likely to develop tolerance: 
Select and explain. 
A. Sustained release oral nitroglycerine, B. Sublingual nitroglycerine, C. Transdermal nitroglycerine, D. Oral pentaerythritol tetranitrate
B: Sublingual nitroglycerine
Answer: B: Sublingual nitroglycerine 
Explanation: Tolerance develops to nitrates, when these are present constantly in the blood. Sublingual route leads to immediate action of nitrates and these act for a sho time. Other preparations mentioned in the question are more likely to give consistent plasma levels of nitrates leading to development of tolerance.