after being informed about the study and potential risks. All patients giving written consent will be randomized by double blind manner into 2 groups each one containing 30 patients , (Group M) : will be given intravenous infusion of magnesium sulfate at a dose of 4 gm intravenously over 20 min as a loading dose then MgSO4 intravenous infusion is continued at a rate of 1 gm/h for 24 h or until obtain and stabilize the targeted blood pressure..
(Group L) : The patients will be given intravenous infusion of labetalol (Trandate™,) available in 20 ml ampoules containing 100mg labetalol (5mg/ml). Starting the infusion with 20mg/h and then titrate to obtain and stabilize the targeted blood pressure by adjusting the infusion as required every 15 - 30min to a maximum dose of 160mg/hr.
