Prophylactic anticonvulsants for prevention of immediate and early postcraniotomy seizures. Comparative double blind clinical trial of phenytoin and sodium valproate as anticonvulsant prophylaxis after craniotomy: efficacy, tolerability, and cognitive effects. Do prophylactic anticonvulsant drugs alter the pattern of seizures after craniotomy? Influence of surgery and antiepileptic drugs on seizures symptomatic of cerebral tumours. Phenytoin and postoperative epilepsy. A double-blind study.
Phenytoin (15 mg/kg) was administered intravenously to 189 patients shortly before their intracranial, supratentorial surgery was completed. Intravenous phenytoin of 5-6 mg/kg/day in three divided doses was administered daily for the first 3 postoperative days. Therapeutic serum levels (10-20 micrograms/mL) were achieved in 113 (59.8%) patients. An equally constituted, randomized control group of 185 patients received a placebo under identical conditions. The group receiving phenytoin had only one immediate and two early postoperative seizures. The 185 controls had four immediate and nine early postoperative seizures. None of the follow-up computed tomography scans of the patients with seizures showed postoperative hematoma. One patient had a significant tension pneumocranium, a possible cause of postoperative seizures. To avoid a decrease in the serum anticonvulsant level due to intraoperative blood loss, it is suggested that for patients who need an urgent or emergent craniotomy, prophylatic anticonvulsant medication should be given at least 20 minutes before completion of wound closure. To determine the efficacy, tolerability, and impact on quality of life and cognitive functioning of anticonvulsant prophylaxis with phenytoin or sodium valproate in patients after craniotomy.
                A prospective, stratified, randomised, double blind single centre clinical trial was performed, comparing two groups of 50 patients each, who underwent craniotomy for different pathological conditions and who were treated for 1 year after surgery with either 300 mg phenytoin/day or 1500 mg sodium valproate/day. During the study period patients were seen in the outpatient clinic at 1.5, 3, 6, and 12 months, when medical history, adverse events, and drug plasma concentrations were evaluated. Neuropsychological functioning and quality of life were assessed on the last three visits. In cases of a seizure an EEG was performed, drug plasma concentration assessed, and medication subsequently increased.
                Of the 100 included patients 14 (seven in each group) experienced one or more postoperative seizures. Severity of the seizures was comparable in the two groups. In all patients, drug plasma concentrations were in the low or subtherapeutic ranges at the time of the first postoperative seizure. Five patients in the phenytoin group and two in the valproate group had to stop their treatment due to drug related adverse events. Sixty patients completed the 12 month period. Analysis of neuropsychological and quality of life data showed no significant differences.
                For efficacy, tolerability, impact on cognitive functioning, and quality of life, no major differences were found between phenytoin and valproate prophylaxis. Valproate is an alternative for anticonvulsant prophylaxis in patients after craniotomy. A total of 276 patients with a high risk of developing postoperative seizures were randomised to treatment with carbamazepine or phenytoin for six or 24 months, or to no treatment. No significant differences were found (though the confidence limits were fairly wide) between the regimes in respect of the incidence of seizures or death. In a substantial proportion of the patients postoperative epilepsy remained a continuing disability. A high incidence of drug-related side effects was found in the treatment groups. Prophylactic anticonvulsants cannot therefore be recommended routinely following supratentorial craniotomy. One hundred and twenty-eight adult patients presenting with and operated on for supratentorial neoplasms were studied. Sixty-five had preoperative seizures and were treated with antiepileptic drugs (AEDs). Among the 63 patients without preoperative epileptic fits, 41 were given AEDs (either phenobarbital or phenytoin) as prophylactic treatment and 22 were not treated. The preoperative epilepsy course was considered with respect to tumour site and histological type. Early and late postoperative seizure occurrence was considered in the different groups of patients. The results suggest the usefulness of a short term preventive treatment with AEDs after surgery in patients without preoperative seizures. In patients with preoperative epilepsy, AEDs should be continued after surgery. However long-term AEDs treatment should not be recommended in patients without preoperative epilepsy. In fact, no significant difference in late seizure occurrence was found between preventively treated and untreated patients. A double-blind trial of phenytoin therapy following craniotomy was performed to test the hypothesis that phenytoin is effective in reducing postoperative epilepsy. A significant reduction in the frequency of epilepsy was observed in the group receiving the active drug up to the 10th postoperative week. Half of the seizures occurred in the first 2 weeks and two-thirds within 1 month of cranial surgery. High rates of epilepsy were observed after surgery in patients with meningioma, metastasis, aneurysm, and head injury. Routine prophylaxis with phenytoin (in a dosage of 5 to 6 mg/kg/day) would seem to be indicated, particularly in high-risk patients and, where possible, this treatment should be started 1 week preoperatively. Seizure control is best when therapeutic levels of phenytoin are maintained.
There is little evidence to suggest that AED treatment administered prophylactically is effective or not effective in preventing post-craniotomy seizures. The current evidence base is limited due to the differing methodologies employed in the trials and inconsistencies in reporting of outcomes. Further evidence from good-quality, contemporary trials is required in order to assess the effectiveness of prophylactic AED treatment compared to control groups or other AEDs in preventing post-craniotomy seizures properly.