Effect of phenobarbital on seizure frequency and mortality in childhood cerebral malaria: a randomised, controlled intervention study.

BACKGROUND: Seizures commonly complicate cerebral malaria and are associated with an increased risk of death and neurological sequelae. We undertook a randomised study to assess the efficacy of intramuscular phenobarbital in preventing seizures in childhood cerebral malaria. METHODS: Children with cerebral malaria admitted to one hospital in Kilifi, Kenya, were randomly assigned a single intramuscular dose of phenobarbital (20 mg/kg) or identical placebo. Clinical tolerance was assessed at the start of the trial, with particular reference to respiratory depression and hypotension. Seizures were timed and recorded, and treated in a standard way. Plasma phenobarbital concentrations were measured. Analyses were by intention to treat. FINDINGS: 440 children with cerebral malaria were admitted to the hospital; 100 were not recruited to the study. Of the remaining 340, 170 received phenobarbital and 170 placebo. The drug was adequately absorbed and well tolerated. Seizure frequency was significantly lower in the phenobarbital group than in the placebo group (18 [11%] vs 46 [27%] children had three or more seizures of any duration; odds ratio 0.32 [95% CI 0.18-0.58]) but mortality was doubled (30 [18%] vs 14 [8%] deaths; 2.39 [1.28-4.64]). The frequency of respiratory arrest was higher in the phenobarbital group than in the placebo group, and mortality was greatly increased in children who received phenobarbital plus three or more doses of diazepam (odds ratio 31.7 [1.2-814]). INTERPRETATION: In children with cerebral malaria, phenobarbital 20 mg/kg provides highly effective seizure prophylaxis but is associated with an unacceptable increase in mortality. Use of this dose cannot, therefore, be recommended.

PIP: This randomized, placebo-controlled study assesses whether a single intramuscular dose of phenobarbital (20 mg/kg) given on admission to Kenyan children with cerebral malaria could lower the frequency of seizures, which complicate cerebral malaria by increasing the risk of death and neurological sequelae. A total of 340 children with cerebral malaria were admitted to the hospital; 170 received phenobarbital and 170 received placebo. The drug was adequately absorbed and well tolerated. Findings revealed a significantly lower frequency of seizures in the phenobarbital group than in the placebo group (18 [11%] vs. 46 [27%] children had 3 or more seizures of any duration; odds ratio (OR), 0.32; 95% confidence interval (CI), 0.18-0.58). However, mortality was doubled (30 [18%] vs. 14 [8%] deaths; OR, 2.39; 95% CI, 1.28-4.64) in the phenobarbital group. In addition, the frequency of respiratory arrest was higher in the phenobarbital group than in the placebo group, and mortality was greatly increased in children who received phenobarbital plus 3 or more doses of diazepam. In conclusion, although the phenobarbital dose of 20 mg/kg given to children with cerebral malaria provides highly effective seizure prophylaxis, an unacceptable increase in mortality is noted; hence, use of this dosage is not recommended.

Chloroquine is not a risk factor for seizures in childhood cerebral malaria.

OBJECTIVES: There are a number of case reports in the medical literature suggesting an association between the ingestion of chloroquine and subsequent seizure activity. Our study was designed to investigate the relationship between blood levels of chloroquine (CQ), its metabolite desethylchloroquine (DCQ), and seizures in children admitted to hospital with cerebral malaria. METHODS: Serial blood levels of CQ and DCQ were measured over the first 24 h of hospital admission in children with cerebral malaria. The number and duration of all seizures was recorded, and statistical analysis subsequently performed to determine the relationship between seizure activity and blood concentrations of CQ and DCQ. RESULTS: Chloroquine was detected in 92% (100/109) of admission blood samples. 54% (59/109) of the patients had one or more seizures after admission, while 8% (9/109) had an episode of status epilepticus. Median (interquartile range) baseline concentrations of CQ and DCQ were, respectively, 169.4 microg/ml (75.1-374.9) and 352.3 microg/ml (81.9-580.1) for those children who had seizures after admission, compared to CQ 227.5 microg/ml (79.4-430.2) and DCQ 364.0 microg/ml (131.3-709.4) for those who did not have seizures (P > 0.5 for all comparisons). Baseline concentrations of CQ and DCQ were not significantly associated with the occurrence of seizures lasting for 5 min or more. The nine children who had an episode of status epilepticus had significantly lower median admission levels of CQ than those without status epilepticus: 75.1 microg/l (7.4-116.5) vs. 227.5 microg/l (85.6-441.2), P = 0.02. Multivariate logistic regression analysis, taking into account factors likely to affect the risk of seizures in hospital, failed to change the significance of these results. CONCLUSIONS: These findings suggest that chloroquine does not play an important role in the aetiology of seizures in childhood cerebral malaria.