A randomized controlled trial of phenobarbital in neonates with hypoxic ischemic encephalopathy

Novel Therapeutics for Neonatal Seizures

Neonatal seizures are a common neurologic emergency for which therapies have not significantly changed in decades. Improvements in diagnosis and pathophysiologic understanding of the distinct features of acute symptomatic seizures and neonatal-onset epilepsies present exceptional opportunities for development of precision therapies with potential to improve outcomes. Herein, we discuss the pathophysiology of neonatal seizures and review the evidence for currently available treatment. We present emerging therapies in clinical and preclinical development for the treatment of acute symptomatic neonatal seizures. Lastly, we discuss the role of precision therapies for genetic neonatal-onset epilepsies and address barriers and goals for developing new therapies for clinical care.

Oxytocin mediates neuroprotection against hypoxic-ischemic injury in hippocampal CA1 neuron of neonatal rats

Neonatal hypoxic-ischemic encephalopathy (NHIE) is one of the most prevalent causes of death during the perinatal period. The lack of exposure to oxytocin is associated with NHIE-mediated severe brain injury. However, the underlying mechanism is not fully understood. This study combined immunohistochemistry with electrophysiological recordings of hippocampal CA1 neurons to investigate the role of oxytocin in an in vitro model of hypoxic-ischemic (HI) injury (oxygen and glucose deprivation, OGD) in postnatal day 7-10 rats. Immunohistochemical analysis showed that oxytocin largely reduced the relative intensity of TOPRO-3 staining following OGD in the hippocampal CA1 region. Whole-cell patch-clamp recording revealed that the OGD-induced onset time of anoxic depolarization (AD) was significantly delayed by oxytocin. This protective effect of oxytocin was blocked by pretreatment with [d(CH2)51, Tyr (Me)2, Thr4, Orn8, des-Gly-NH29] vasotocin (dVOT, an oxytocin receptor antagonist) or bicuculline (a GABA_A receptor antagonist). Interestingly, oxytocin enhanced inhibitory postsynaptic currents in CA1 pyramidal neurons, which were abolished by tetrodotoxin or dVOT. In contrast, oxytocin had no effect on excitatory postsynaptic currents but induced an inward current in 86% of the pyramidal neurons tested. Taken together, these results demonstrate that oxytocin receptor signaling plays a critical role in attenuating neonatal neural death by facilitating GABAergic transmission, which may help to regulate the excitatory-inhibitory balance in local neuronal networks in NHIE patients.

Efficacy and Side Effect Profile of Clobazam in Children with Different Etiologies of Epilepsy from a Single Center

Objectives:

Clobazam is a long-acting antiepileptic drug that belongs to benzodiazepines used in the polytherapy of childhood epilepsy. In this study, our aim is to retrospectively evaluate the effectiveness and side effect profile of clobazam in children with different etiologies of epilepsy, mostly drug resistant.

Methods:

Forty patients aged 0-18 years that were admitted to Okmeydanı Training and Research Hospital pediatric neurology outpatient clinic between January 2017–January 2019 and prescribed clobazam were included in this study. The data of the patients who gave informed consent were extracted retrospectively from the outpatient clinic files. The patients with no seizures over 50% reduction in seizures were classified as clobazam-responsive, whereas the patients with less than 50% reductions in seizures, patients who had no response, and who manifested side effects and stopped using the drug were classified as clobazam-unresponsive.

Results:

Twenty-three of the patients (57.5%) were male, 17 were (42.5%) were female. The average onset age of epilepsy was 31.8±37.2 months, while the average age for the prescription of clobazam was 70.6±48.9 months. The types of seizures were focal in 23 patients (57.5%) and generalized in 17 (42.5%) patients. Thirty-three (82.5%) patients had been using double or triple combinations of eight different antiepileptic drugs when clobazam was added to their treatment and accepted as drug-resistant epilepsy. The etiology of twenty one patients (52.5%) was unknown. In the remaining 19 patients (47.5%), the most common cause was structural and others were genetic, infectious and metabolic. Thirty one of the patients (77.5%) were responsive to clobazam. Of them, fifteen (37.5%) had no seizures, and 16 had a reduction in seizures (>50%). Nine (22.5%) patients were accepted as unresponsive to clobazam. The mean dose per kg was 0.7±0.3 mg/kg/day with a median of 0.63 mg/kg/day. Side effects of clobazam were encountered in 18 patients (45%); these resulted in the cessation of administration in only six (15%) patients. The side effects that cause the cessation of clobazam were sedation, refusal to take the drug due to the taste, irritability, hypersalivation, and malaise. Four patients (10%) had their doses reduced, seven patients (17.5%) responsive to clobazam although with side effects continued taking the drug as prescribed. The most common side effects of all were hyperactivity and sedation consecutively.

Conclusion:

Clobazam is an effective treatment for ensuring seizure freedom in pediatric epilepsy, mostly drug-resistant. The side effects are at tolerable levels in patients who are responsive to the drug.

Prophylactic barbiturate use for the prevention of morbidity and mortality following perinatal asphyxia

BACKGROUND

Seizures are common following perinatal asphyxia and may exacerbate secondary neuronal injury. Barbiturate therapy has been used for infants with perinatal asphyxia in order to prevent seizures. However, barbiturate therapy may adversely affect neurodevelopment leading to concern regarding aggressive use in neonates.

OBJECTIVES

To determine the effect of administering prophylactic barbiturate therapy on death or neurodevelopmental disability in term and late preterm infants following perinatal asphyxia.

SEARCH METHODS

We used the standard search strategy of the Cochrane Neonatal Review group to search the Cochrane Central Register of Controlled Trials (CENTRAL, 2015, Issue 11), MEDLINE via PubMed (1966 to 30 November 2015), EMBASE (1980 to 30 November 2015), and CINAHL (1982 to 30 November 2015). We also searched clinical trials databases, conference proceedings, and the reference lists of retrieved articles for randomized controlled trials (RCT) and quasi-RCTs.

SELECTION CRITERIA

We included all RCTs or quasi-RCTs of prophylactic barbiturate therapy in term and late preterm infants without clinical or electroencephalographic evidence of seizures compared to controls following perinatal asphyxia.

DATA COLLECTION AND ANALYSIS

Three review authors independently selected, assessed the quality of, and extracted data from the included studies. We assessed methodologic quality and validity of studies without consideration of the results. The review authors independently extracted data and performed meta-analyses using risk ratios (RR) and risk differences (RD) for dichotomous data and mean difference for continuous data with 95% confidence intervals (CI). For significant results, we calculated the number needed to treat for an additional beneficial outcome (NNTB) or for an additional harmful outcome (NNTH).

MAIN RESULTS

In this updated review, we identified nine RCTs of any barbiturate therapy in term and late preterm infants aged less than three days old with perinatal asphyxia without evidence of seizures. Eight of these studies compared prophylactic barbiturate therapy to conventional treatment (enrolling 439 infants) and one study compared barbiturate therapy to treatment with phenytoin (enrolling 17 infants). Prophylactic barbiturate therapy versus conventional treatment: one small trial reported a decreased risk of death or severe neurodevelopmental disability for barbiturate therapy (phenobarbital) versus conventional treatment (RR 0.33, 95% CI 0.14 to 0.78; RD -0.55, 95% CI -0.84 to -0.25; NNTB 2, 95% CI 1 to 4; 1 study, 31 infants) (very low quality evidence).Eight trials comparing prophylactic barbiturate therapy with conventional treatment following perinatal asphyxia demonstrated no significant impact on the risk of death (typical RR 0.88, 95% CI 0.55 to 1.42; typical RD -0.02, 95% CI -0.08 to 0.05; 8 trials, 429 infants) (low quality evidence) and the one small trial noted above reported a significant decrease in the risk of severe neurodevelopmental disability (RR 0.24, 95% CI 0.06 to 0.92; RD -0.43, 95% CI -0.73 to -0.13; NNTB 2, 95% CI 1 to 8; 1 study, 31 infants) (very low quality evidence).A meta-analysis of the six trials reporting on seizures in the neonatal period demonstrated a statistically significant reduction in seizures in the prophylactic barbiturate group versus conventional treatment (typical RR 0.62, 95% CI 0.48 to 0.81; typical RD -0.18, 95% CI -0.27 to -0.09; NNTB 5, 95% CI 4 to 11; 6 studies, 319 infants) (low quality evidence). There were similar results in subgroup analyses based on type of barbiturate and Sarnat score. Prophylactic barbiturate therapy versus other prophylactic anticonvulsant therapy: one study reported on prophylactic barbiturate versus prophylactic phenytoin. There was no significant difference in seizure activity in the neonatal period between the two study groups (RR 0.89, 95% CI 0.07 to 12.00; 1 trial, 17 infants).

AUTHORS' CONCLUSIONS

We found only low or very low quality evidence addressing the use of prophylactic barbiturates in infants with perinatal asphyxia. Although the administration of prophylactic barbiturate therapy to infants following perinatal asphyxia did reduce the risk of seizures, there was no reduction seen in mortality and there were few data addressing long-term outcomes. The administration of prophylactic barbiturate therapy for late preterm and term infants in the immediate period following perinatal asphyxia cannot be recommended for routine clinical practice. If used at all, barbiturates should be reserved for the treatment of seizures. The results of the current review support the use of prophylactic barbiturate therapy as a promising area of research. Future studies should be of sufficient size and duration to detect clinically important reductions in mortality and severe neurodevelopmental disability and should be conducted in the context of the current standard of care, including the use of therapeutic hypothermia.

Strategies to prevent reperfusion injury to the brain following intrapartum hypoxia-ischemia

Hypoxia-ischemia is an infrequent event which may occur prior to or during delivery, following a period of decreased placental and/or fetal blood flow. Following recovery, a reperfusion phase and secondary energy failure may occur 6-48 h subsequent to the initial insult. Therapeutic hypothermia may be offered to infants at risk for evolving encephalopathy if identified within the 6 h therapeutic window, and should be instituted as early as possible for eligible infants. Additionally, the clinician must pay close attention to supportive measures such as avoidance of hyperthermia, as well as comprehensive management of clinical or electrographic seizures, blood pressure, blood glucoses, and carbon dioxide levels.

Perinatal and early postnatal factors underlying developmental delay and disabilities

A delay in meeting developmental milestones may be secondary to perinatal events, involving complicated interactions between mother and fetus during delivery. Maternal factors including weight, diet, and morbidities can affect neonatal adaptation and later development. Prematurity, low birth weight, and previous intrauterine insults as well as complications during delivery of a previously normal fetus increase the risk for perinatal stress. In this article, the literature on perinatal and early postnatal factors that underlie risks for developmental delay and disabilities is reviewed. Studies that concern neuroprotective therapies and prediction of long-term neurologic outcome by clinical examination, neuroimaging techniques, and electroencephalographic studies are reviewed as well.

How phenobarbital revolutionized epilepsy therapy: the story of phenobarbital therapy in epilepsy in the last 100 years

Phenobarbital (phenobarbitone) was first used as an antiepileptic drug 100 years ago, in 1912. This article tells the story of the discovery of its antiepileptic action, its early development, and the subsequent course of its clinical use over the 100-year period. The side effects, pharmacokinetics, and misuse of barbiturates are considered, along with the more recent clinical trials and the drug's current clinical utilization. The introduction of controlled drug regulations, the comparative cost of phenobarbital, and its inclusion on the World Health Organization (WHO) essential drug list are discussed. It is one of the few drugs on the formulary in 1912 that is still listed today, and remarkably its efficacy in epilepsy has not been significantly bettered. The current recommendation by the WHO is that phenobarbital should be offered as the first option for therapy for convulsive epilepsy in adults and children if availability can be ensured. This is rated as a strong recommendation because of the proven efficacy and low cost of phenobarbital, and despite its perceived side-effect profile and the practical problems of access. Whether this recommendation puts "a hierarchy on the brain," as has been suggested, is arguable. Much still needs to be learned about the drug's effects, and the issues raised by phenobarbital have lessons for all antiepileptic drug therapy.

Treatment of hypoxic-ischemic encephalopathy in newborns

Hypoxic-ischemic (HI) brain injury is the most common cause of encephalopathy and seizures in term newborn infants. There is no single, valid test for birth asphyxia leading to HI brain injury, and thus this disorder is often poorly characterized, and the timing and etiology of the injury can be difficult to ascertain. Optimal management of HI brain injury involves prompt resuscitation, careful supportive care including prevention of hyperthermia and hypoglycemia, and treatment of clinical and frequent or prolonged subclinical seizures. Recent evidence suggests that therapeutic hypothermia by selective head or whole-body cooling administered within 6 hours of birth reduces the incidence of death or moderate/severe disability at 12 to 22 months. Hypothermia is a promising new therapy that physicians should consider within the context of a registry or study. Optimal seizure treatment remains controversial because the most widely used drug, phenobarbital, has limited efficacy, and the value of monitoring and treating subclinical seizures is uncertain. There is compelling need for well-designed clinical trials to address treatment of ongoing brain injury in the setting of hypoxia-ischemia and seizures. Emerging evidence from preclinical studies suggests that future therapy for HI brain injury and neonatal encephalopathy will combine novel neuroprotective and anti-seizure agents. Pilot clinical trials of newer anticonvulsants are ongoing and will provide critical information for care of neonatal seizures.

Effect of high-dose phenobarbital on oxidative stress in perinatal asphyxia: an open label randomized controlled trial

OBJECTIVE

To evaluate the effect of high dose phenobarbital on lipid peroxidation and antioxidant enzymes in perinatal asphyxia.

DESIGN

Open label, Randomized controlled trial.

SETTING

Neonatal intensive care unit of a tertiary care teaching hospital.

PARTICIPANTS

72 full term inborn neonates with severe birth asphyxia.

METHODS

Neonates were randomized to Study (phenobarbital) group and Control group. The infants in the study group received phenobarbital infusion (40 mg/kg) within first two hours of life while babies in the control group did not receive any phenobarbital. Rest of the management in both the groups was as per the unit protocol for the management of hypoxic ischemic encephalopathy. A cerebrospinal fluid examination was done at 12 ± 2 hours of life to determine the levels of superoxide dismutase, glutathione peroxidise and malonyldialdehyde. 60 neonates were followed up at 1 month of age when a detailed neurological examination was done.

RESULTS

Four neonates in the study group and six neonates in the control group died during the study. Two neonates in the study group were lost to follow up. The cerebrospinal fluid lipid peroxides and antioxidant enzymes were significantly lower in the phenobarbital group as compared to the control group. The neurological outcome at one month follow up was found to be comparable between the two groups.

CONCLUSION

Phenobarbital (40 mg/kg) given in the first two hours of life in term neonates with perinatal asphyxia led to a decrease in CSF levels of lipid peroxides and antioxidant enzymes at 12 ± 2 hours of life.

Prophylactic phenobarbital and whole-body cooling for neonatal hypoxic-ischemic encephalopathy

In infants with hypoxic-ischemic encephalopathy, cooling reduces death/neurodevelopmental impairment, whereas prophylactic anticonvulsants may not. This retrospective analysis shows no reduction in neurodevelopmental impairment (23% in prophylactic phenobarbital group vs 45% in controls, P = .3) but fewer clinical seizures in cooled infants who received prophylactic phenobarbital (15% vs 82% P < .0001).

Successful treatment of profound hypothermia of the newborn

We report a case of a profoundly hypothermic newborn with a core temperature of 25 degrees C with a successful recovery and normal neurological outcome at 3 and 6 months. This term male infant had been exposed to a temperature of -3 degrees C for approximately 30 min. Slow re-warming, using external modalities was used in addition to volume expansion, heparinization, antibiotics and sedation. There is limited information available concerning the safest and most effective method of re-warming hypothermic newborns. Slow re-warming has been advocated as it replicates the normal physiological process in a neonate, which minimizes a negative therapy impact.

CONCLUSION

The most significant decision regarding treatment is the identification of the most appropriate method and speed of re-warming. This report supports recommendations for gradual re-warming of a severely hypothermic newborn. Physiological cardiovascular mechanisms seemed to be intact during slow re-warming; this might be applicable to the treatment of profound hypothermia of the newborn.