Magnesium sulphate in management of pre-eclampsia (dosing)

Dosing of magnesium sulphate in management of pre-eclampsia

Using magnesium sulphate as a neuroprotective agent against seizures is a well known fact. We have been taught to follow Pritchard's regimen all through medical school, but actually dealing with it in the labour ward is a whole other scenario!

In the Indian setup (especially a government setup), magnesium sulphate is not always found in the concentration it is to be administered.

The regimen calls for using:
0 hr dose of 4g 20% concentration MgSO4 IV, followed by 10g 50% MgSO4 given IM.
A maintenance dose of 50% MgSO4 is given 4 hourly.

However, MgSO4 is generally found in vials with 50% concentration. The following picture illustrates how to convert that to a 20% concentration solution for administering a loading dose of MgSO4.

Magnesium sulphate in management of pre-eclampsia (dosing) 

Hope that helps!

This post was written by our Medical Student Guest Author, Shruti Sanghvi. She said it was frequently asked in her vivas!