This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Pregnancy, Subject name: Pharmacology
Drug used to prevent premature birth includes all except- 
Select and explain. 
A. Ritodrin, B. Ergometrine, C. Magnesium sulfate, D. Atosiban
B: Ergometrine
Answer: B: Ergometrine 
Explanation: Ans. is 'b'i.e., Ergometrine Tocolyticso These drugs are used to decrease uterine contractions to delay the labour when there is premature onset of contraction. Tocolytic drugs are b2-agonists (ritodrin), magnesium sulfate, ethyl alcohol, progesterone, diazoxide, calcium channel blocker (nifedipine), atosiban (oxytocin antagonist), NSAIDs and nitrate.