This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Medical, surgical and gynaecological illness complicating pregnancy, Subject name: Gynaecology & Obstetrics
True about MgSO4 
Select and explain. 
A. Not a tocolytic, B. Used In management of eclampsia, C. Doesnt Cause neonatal respiratory depression, D. Can be given in myasthenia gravis
B: Used In management of eclampsia
Answer: B: Used In management of eclampsia 
Explanation: The drug of choice for control and prevention of convulsion in eclampsia is magnesium sulphate ,usually given by Pritchard&;s regime.The mechanism of action thought to have a peripheral action at the neuromuscular junction,by competing with calcium for entry into the cells.It may also have central action.It is used as tocolytic also.in case of magnesium toxicity,there can be respiratory depression.Absolute contraindications are Myasthenia gravis and myocardial infarction. TEXT BOOK OF OBSTETRICS,Sheila Balakrishnan,2nd edition,page no.268