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Query: UMLS:C0036572 (seizures)
 80,221 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Magnesium sulfate is used for seizure prophylaxis in patients with preeclampsia. It also has significant effects on calcium metabolism and could, therefore, alter the pressor response to calcium-dependent vasoconstrictors. The present in vivo rat study examined the effect of magnesium sulfate to alter the pressor response to norepinephrine (NE) and angiotensin II (A II). Magnesium doses were chosen to approximate those used in treating preeclampsia. NE resulted in a significant rise in mean arterial pressure (delta MAP, 46 +/- 3.7 mmHg; p < 0.001). A II also resulted in a significant rise in MAP (delta MAP, 23 +/- 3.6 mmHg, p < 0.02). Magnesium sulfate alone had no significant effect on MAP but attenuated the pressor response to both NE (delta MAP, 16 +/- 1.5 mmHg) and A II (delta MAP, 12 +/- 2.5 mmHg). After discontinuation of the magnesium sulfate infusion, the control pressor responses to NE and A II were again seen (delta MAP, 39 +/- 3.5 mmHg and delta MAP, 28 +/- 4.2 mmHg, respectively). Although magnesium sulfate is not a primary antihypertensive agent, it may have effects on blood pressure by attenuating the actions of circulating vasoconstrictors.
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PMID:Effect of magnesium sulfate on the vascular actions of norepinephrine and angiotensin II. 141 60

A randomized prospective trial has shown that folic acid started before conception and continued for the first trimester reduces the risk of recurrence of neural tube defects by 72% in women with a previously affected child. Carbamazepine exposure in utero is associated with a 1% risk of spina bifida. Long-term follow-up of antenatal exposure to phenobarbital and carbamazepine in two groups of infants shows no neurologic differences between the two groups. Magnesium sulfate is more effective in prevention of recurrent eclamptic seizures than phenytoin. During pregnancy, the need for thyroxine increases in many women. Vitamin B6 and ginger are both effective for nausea and vomiting in early pregnancy. Low-dose aspirin does not change the course of preeclampsia when it is started after the diagnosis is made. Angiotensin-converting enzyme inhibitors cause significant disturbances of fetal and neonatal renal function. Prophylactic beta-adrenergic agents fail to prevent prematurity in twins. Oral tocolysis with magnesium chloride or ritodrine is no more effective than observation alone. The risk of primary pulmonary hypertension in the newborn after indomethacin tocolysis is increased with prolonged therapy. Lithium causes polyhydramnios from fetal diabetes insipidus in utero. Treatment of Ureaplasma urealyticum infection with erythromycin during pregnancy does not eliminate the organism from the lower genital tract and does not improve perinatal outcome.
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PMID:Drug therapy during pregnancy. 154 29

The characteristics and treatment of preeclampsia and eclampsia are reviewed. Risk factors for preeclampsia include (1) nulliparity, (2) a mother or sister(s) with a history of the disorder, (3) essential hypertension or renal disease, or (4) a twin or molar pregnancy. Preeclampsia is diagnosed when the systolic blood pressure (BP) increases by 30 mm Hg or the diastolic BP increases by 15 mm Hg after the 20th week of gestation and the BP rise is accompanied by edema, proteinuria, or both. Severe preeclampsia is diagnosed when the BP reaches or exceeds 160 mm Hg systolic or 110 mm Hg diastolic after bed rest. Eclampsia is the occurrence of seizures (in the preeclamptic patient) that cannot be attributed to other causes; it occurs in about 0.2% of preeclamptic patients. Magnesium sulfate (in the injectable, hydrated form) is the agent used most often for seizure prophylaxis in the preeclamptic patient in the United States. It is also used widely to control seizures once they develop. In the United States, diazepam is used to supplement magnesium sulfate if necessary to control seizures, but its use is not routine. Among antihypertensive agents, i.v. hydralazine is preferred in this country to control blood pressure in the severely preeclamptic or eclamptic patient. Several studies provide promising evidence that low-dose aspirin (60-150 mg daily beginning at 28-30 weeks of gestation) prevents preeclampsia in women who are at risk for its development. Until additional comparative studies are completed, magnesium sulfate and hydralazine will remain the standard of care for the treatment of preeclampsia in the United States.
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PMID:Treatment of preeclampsia and eclampsia. 161 13

Seizure prophylaxis is standard intrapartum therapy for patients with pregnancy-induced hypertension. Magnesium sulfate is used in the United States in spite of limited literature comparing its efficacy with other anticonvulsants. Fifty patients with pregnancy-induced hypertension were prospectively randomized to receive magnesium sulfate or phenytoin for seizure prophylaxis. Patients were observed for toxicity, side effects, and labor outcomes, and the neonates were evaluated for side effects of the therapy. Three patients were excluded with adverse reactions to medications (one in magnesium sulfate group, two in phenytoin group). No differences were found in patient tolerance, adverse reactions, or neonatal outcomes between groups. Maternal free phenytoin levels were 13.0% +/- 0.4% of total phenytoin (serum albumin, 2.5 to 3.5 gm/dl), significantly higher than in nonpregnant patients. Neither free phenytoin levels nor percentage of total phenytoin that was free correlated significantly with maternal albumin levels. The pharmacokinetics of phenytoin loading in the massively obese pregnant patient may differ and require further evaluation. Phenytoin is a well-tolerated alternative to magnesium sulfate for seizure prophylaxis in the patient with mild pregnancy-induced hypertension.
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PMID:Magnesium sulfate versus phenytoin for seizure prophylaxis in pregnancy-induced hypertension. 195 52

Magnesium sulfate is commonly used in tocolytic regimens and as prophylaxis against seizures. Nifedipine may be used simultaneously in either situation. With the isolated perfused rat heart model (Sprague-Dawley rats), we investigated the effects of these agents on cardiac function. Whereas each agent alone depressed cardiac performance, the two drugs together had maximal depressive effects on the heart.
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PMID:Nifedipine enhances the cardiac toxicity of magnesium sulfate in the isolated perfused Sprague-Dawley rat heart. 238 58

Magnesium sulfate has been used as an anticonvulsant in the treatment of eclampsia, but efficacy of magnesium in other types of seizure disorders is poorly documented. We examined the effects of magnesium sulfate (MgSO4) on seizures produced in mice by maximal electroshock (MES) and pentylenetetrazol (PTZ), MgSO4 injection (6.7 mEq/kg i.p.) caused weakness in all animals. With suprathreshold electroshock, 10/10 controls and 11/12 treated animals had seizures with tonic hind limb extension (P = NS). Electroshock threshold was unaltered by magnesium treatment (n = 48; P = 0.47). PTZ induced clonic seizures in 12/12 controls and 5/14 treated animals (P less than 0.05). This difference was likely due to muscular weakness because frequency of EEG spikes was the same in PTZ and PTZ + MgSO4 groups. Mean serum magnesium levels were 2.3 +/- 0.3 mEq/l in animals not given MgSO4; 10.9 +/- 1.4 mEq/l and 12.8 +/- 2.2 mEq/l in treated animals with and without seizures (P = NS). We conclude that magnesium sulfate had no significant anticonvulsant activity in mouse MES and PTZ models for epilepsy. The relevance of these findings to the possible efficacy of magnesium sulfate in eclamptic seizures and other types of epilepsy remains to be determined.
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PMID:Parenteral magnesium sulfate fails to control electroshock and pentylenetetrazol seizures in mice. 261 92

Selected articles on hypertensive diseases in pregnancy from the past year are highlighted. The concept that endothelial cell dysfunction plays an important role in the pathogenesis of preeclampsia has been strengthened. The initial inciting event is still unclear, but inadequate implantation and decreased antioxidant activity may play a role. Magnesium sulfate is still the anticonvulsant of choice for seizure prophylaxis, but the exact mechanism of its action remains controversial. The ideal screening test to identify those patients likely to develop preeclampsia is still lacking, and the side effects and risks of aspirin prophylaxis are not yet known. The results from the National Institutes of Health-sponsored multicenter trial on this subject should be forthcoming.
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PMID:Hypertension in pregnancy. 842 34

Eclampsia is a leading cause of maternal mortality. The prevention of seizure activity in pre-eclampsia and recurrent seizures in eclamptic patients is an essential aspect of management. Many drugs with anticonvulsant properties have been used to treat patients with pre-eclampsia and eclampsia. Magnesium sulfate is a significantly better drug than either diazepam or phenytoin for preventing recurrent seizures in eclamptic patients. Magnesium sulfate has diverse cardiovascular and neurological effects and also alters calcium metabolism. Although the drug crosses the placenta and may affect the fetus, these effects are clinically small and fetal morbidity has been shown to be reduced in randomised studies comparing magnesium sulfate to either phenytoin or benzodiazepines. Dosage regimens of magnesium sulfate are empirical. Because adverse effects of this agent are related to toxicity, the establishment of greater efficacy by using higher dosage regimens needs to be tested against a greater risk of adverse effects. The most serious toxicity related to magnesium sulfate use is magnesium sulfate use is neuromuscular blockade that may result in respiratory arrest. Magnesium sulfate is now the drug choice for treating eclamptic patients. However, further studies are required to establish the role of this agent as a prophylactic agent in the prevention of eclampsia.
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PMID:Role of magnesium sulfate in seizure prevention in patients with eclampsia and pre-eclampsia. 887 73

Randomized trials are the optimal approach for evaluations of treatment efficacy but may not always be feasible. We study the adequacy of the case-control design in evaluating efficacy in a situation where the investigated therapy, namely the administration of magnesium sulfate for the prevention of eclampsia in patients with preeclampsia, has a suspected strong protective effect. A total of 66 cases of eclampsia were ascertained from among deliveries occurring between 1977 and 1992 at two hospitals in Houston, Texas. Randomly selected preeclamptic controls were matched to cases based on hospital and month of delivery. Magnesium sulfate administration prior to seizure occurrence had a strong protective effect against eclampsia in patients with preeclampsia (OR, 0.02; 95% CI, 0.01-0.05). This protective effect remained when controls were stratified by the degree of severity of preeclampsia (mild-to-moderate OR, 0.03, 95% CI, 0.01-0.09 and severe OR, 0.005; 95% CI, 0.0005-0.04) and when cases were stratified by the timing of the first seizure (antepartum and intrapartum seizures OR, 0.01; 95% CI, 0.003-0.05 and postpartum seizures OR, 0.03; 95% CI, 0.005-0.15). The effect also remained after adjustment for other important predictors in a multivariate logistic regression model (OR, 0.11; 95% CI, 0.03-0.38). The results of this study are in support of a recent randomized trial on the efficacy of magnesium sulfate as a prophylactic agent against eclampsia. Although there are serious potential sources of bias in this study, the magnitude of the protective effect of magnesium sulfate minimizes the likelihood that this effect can be explained by bias. Observational studies could be appropriate complements or alternatives to randomized trials in situations where a strong treatment effect is expected.
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PMID:A case-control evaluation of treatment efficacy: the example of magnesium sulfate prophylaxis against eclampsia in patients with preeclampsia. 917

Eclampsia continues to be a major cause of maternal morbidity and mortality rates, especially in underdeveloped nations. Our data indicate that eclampsia may represent the end stage of at least two very different pathophysiological pathways: one in which cerebral perfusion is low because of vasospasm and another in which cerebral perfusion is increased because of abnormal autoregulation and a failure of the normal protective mechanisms. Magnesium sulfate has been extensively used in the management and prevention of eclamptic seizures in the United States and has been recently shown to be superior to both diphenylhydantoin and diazepam. We have shown that magnesium sulfate is a potent vasorelaxant and that its action may depend on improving cerebral perfusion. Nimodipine, a calcium channel blocker with selective cerebrovascular effect, is currently under investigation in severe preeclampsia. The data show that it is as effective as magnesium sulfate in preventing eclampsia, with less maternal and fetal side effects. Magnesium sulfate and nimodipine have opposite effects on the estimated cerebral perfusion pressure as determined with the Doppler ultrasound. We speculate that the estimated cerebral perfusion pressure may be used to determine the type of cerebrovascular abnormality and the most appropriate treatment in each individual patient with preeclampsia.
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PMID:Prevention of eclampsia. 1010 72


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