This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Gynaecology & Obstetrics
Which of the following drug is not used in the treatment of preterm labour? 
Select and explain. 
A. Ritodrine, B. MgSO4, C. Salbutamol, D. Chlorpromazine
D: Chlorpromazine
Answer: D: Chlorpromazine 
Explanation: Ritodrine, salbutamol and magnesium sulphate are tocolytic drugs used to terminate preterm labour and delivery. Other tocolytic drugs are isoxsuprine, indomethacin, calcium channel blockers, glyceryl trinitrate, atosiban and glyceryl trinitrate. Reference: Textbook of Obstetrics By D C Dutta, 6e page 508.