Clinical pharmacokinetic properties of magnesium sulphate in women with pre-eclampsia and eclampsia.

<bold>Background: </bold>The pharmacokinetic basis of magnesium sulphate (MgSO4 ) dosing regimens for eclampsia prophylaxis and treatment is not clearly established.<bold>Objectives: </bold>To review available data on clinical pharmacokinetic properties of MgSO4 when used for women with pre-eclampsia and/or eclampsia.<bold>Search Strategy: </bold>MEDLINE, EMBASE, CINAHL, POPLINE, Global Health Library and reference lists of eligible studies.<bold>Selection Criteria: </bold>All study types investigating pharmacokinetic properties of MgSO4 in women with pre-eclampsia and/or eclampsia.<bold>Data Collection and Analysis: </bold>Two authors extracted data on basic pharmacokinetic parameters reflecting the different aspects of absorption, bioavailability, distribution and excretion of MgSO4 according to identified dosing regimens.<bold>Main Results: </bold>Twenty-eight studies investigating pharmacokinetic properties of 17 MgSO4 regimens met our inclusion criteria. Most women (91.5%) in the studies had pre-eclampsia. Baseline serum magnesium concentrations were consistently <1 mmol/l across studies. Intravenous loading dose between 4 and 6 g was associated with a doubling of this baseline concentration half an hour after injection. Maintenance infusion of 1 g/hour consistently produced concentrations well below 2 mmol/l, whereas maintenance infusion at 2 g/hour and the Pritchard intramuscular regimen had higher but inconsistent probability of producing concentrations between 2 and 3 mmol/l. Volume of distribution of magnesium varied (13.65-49.00 l) but the plasma clearance was fairly similar (4.28-5.00 l/hour) across populations.<bold>Conclusion: </bold>The profiles of Zuspan and Pritchard regimens indicate that the minimum effective serum magnesium concentration for eclampsia prophylaxis is lower than the generally accepted level. Exposure-response studies to identify effective alternative dosing regimens should target concentrations achievable by these standard regimens.<bold>Tweetable Abstract: </bold>Minimum effective serum magnesium concentration for eclampsia prophylaxis is lower than the generally accepted therapeutic level. [ABSTRACT FROM AUTHOR]