The efficacy of phenytoin in relation to serum levels in severe pre-eclampsia and eclampsia.
OBJECTIVE
To investigate the efficacy of phenytoin in relation to total and free serum levels in patients with severe pre-eclampsia and eclampsia.


METHODS
Prospective descriptive study.


METHODS
Labour Ward, King Edward VIII Hospital, Durban, South Africa. Tertiary referral centre serving an underprivileged community.


METHODS
Eleven patients admitted with a hypertensive crisis. Four patients had eclampsia and 7 had impending eclampsia.


METHODS
Free and total phenytoin levels; efficacy of phenytoin as an anticonvulsant and side-effects of therapy.


RESULTS
Although total phenytoin levels were within the therapeutic range, free phenytoin levels were abnormally high in all patients. Three patients (2 with eclampsia and 1 with imminent eclampsia) each had a seizure after phenytoin treatment had been initiated.


CONCLUSIONS
Neither total nor free phenytoin levels were good predictors of seizure control. It is postulated that the poor performance of phenytoin as an anticonvulsant in severe eclampsia may relate to inadequate distribution of the drug to the brain as a result of cerebral oedema and poor cerebral perfusion rather than paradoxical seizure activity associated with high free phenytoin levels.
Naidu
S
S
Department of Obstetrics and Gynaecology, Faculty of Medicine, University of Natal, Durban, South Africa.
Moodley
J
J
Botha
J
J
McFadyen
L
L
D000293:Adolescent; D000328:Adult; D004305:Dose-Response Relationship, Drug; D004461:Eclampsia / Q000097:blood* / Q000188:drug therapy; D005260:Female; D006801:Humans; D010672:Phenytoin / Q000009:adverse effects / Q000097:blood* / Q000627:therapeutic use*; D011225:Pre-Eclampsia / Q000097:blood / Q000188:drug therapy; D011247:Pregnancy; D011256:Pregnancy Outcome; D011446:Prospective Studies
D010672:Phenytoin