The therapeutic index of magnesium is said to be low, hence, there are
fears of toxicity when used as anticonvulsant in eclamptic patients.
The objective of this study was to determine the serum levels of
magnesium in eclamptic patients treated with magnesium sulphate and
relate the levels with clinical indicators. It was a prospective study
involving consecutive eclamptic patients that were managed between
January and December 2002, with magnesium sulphate as the sole
anticonvulsant agent, using a modified Pritchard regimen. Blood samples
were taken before the administration of the loading and maintenance
doses of magnesium sulphate and serum levels of magnesium were
estimated using the Jenway 605 colorimeter. There were 19 patients and
72 blood samples. The mean baseline serum magnesium was 0.72 ±
0.10mmol/L while serum magnesium levels when the patients were on
treatment ranged from 1.95 to 2.82mmol/L. No serum magnesium level was
greater than 3.0mmol/L and none of the patients had clinical evidence
of magnesium toxicity. We conclude that serum magnesium levels in these
patients were within the therapeutic range, therefore, routine
estimation of this cation is not necessary. Even where the laboratory
facility is available, it is suggested that serum estimation be limited
to cases where clinical monitors suggest toxicity. (Afr J Reprod Health
2005; 9[1]: 128-132
