Phenobarbital as Anticonvulsant Prophylaxis in Patients With Traumatic Brain Injury at Risk for Alcohol Withdrawal Syndrome

Background: Anticonvulsant prophylaxis (ACP) for early post-traumatic seizures (PTS) is recommended in patients with traumatic brain injury (TBI). Phenobarbital (PB) may be used to prevent alcohol withdrawal syndrome (AWS) in at-risk patients. The dual-purpose use of PB in the TBI population would allow for consolidation of pharmacotherapy. Objective: The primary objective of this study was to determine the frequency of early PTS in TBI patients at risk of AWS treated with PB as ACP. Secondary objectives included determining rates of over sedation and endotracheal intubation. Methods: Patients received an intravenous (IV) loading dose of PB at 15-20 mg/kg followed by 1 mg/kg every 12 hours for 7 days with a goal level of 15-20 mcg/mL. Medication data, seizure frequency, and episodes of over sedation and endotracheal intubation were collected. Results: Eighty patients were treated with PB over a 1-year period. Thirty-nine patients were analyzed. Median loading dose was 19.9 (Interquartile Range 19.1-20.0) mg/kg with a median post load level of 21.7 mcg/mL (IQR 18.3-25.8) mcg/mL. One patient (2.6%) had electrographic evidence for early PTS. PB was discontinued in 4 (10.3%) patients out of concern for over sedation. One patient required endotracheal intubation after rapid PB loading. Conclusion: The frequency of early PTS was low when PB was used as primary ACP in patients with TBI at risk for AWS. Over sedation is a potential adverse effect that should be considered in the choice of ACP. No conclusions can be drawn as to the effectiveness of PB in preventing AWS.

The Impact of Strong Inducers on Direct Oral Anticoagulant Levels

PURPOSE

The concomitant use of direct oral anticoagulants (DOAC) and strong P-glycoprotein (P-gp) and cytochrome P450 3A4 (CYP3A4) inducers may lead to reduced DOAC levels and therapeutic failure. This study aimed to describe DOAC concentrations in patients receiving strong P-gp and CYP3A4 inducers, in relation to individual risk factors for high or low DOAC levels.

METHODS

We retrospectively identified hospitalized patients simultaneously receiving a DOAC and carbamazepine, phenobarbital, phenytoin, or rifampicin between 2016 and 2021. Among them, patients who underwent DOAC measurement at steady state were included. DOAC peak or trough levels were compared with on-therapy ranges observed in pivotal trials. Individual risk factors for high or low DOAC levels were identified.

RESULTS

We included 17 patients (median age 75 years), mainly receiving apixaban and carbamazepine. For 5 patients (29%), DOAC trough or peak level was below the expected range. Among the remaining 12 patients, 8 had at least one measurement in the lower quartile of the range. The median number of risk factors for drug accumulation was 0 (range 0-1) in patients with ≥1 measurement below the range and 2 (range 0-3) in other patients. DOAC measurement led to treatment adjustments in 9 patients (DOAC dose increase or switch).

CONCLUSION

Our data suggest a significant risk of reduced DOAC levels in patients taking strong P-gp and CYP3A4 inducers, especially those without risk factors for drug accumulation. DOAC measurement could help manage this relevant drug-drug interaction.

Researching on the compliance of epilepsy patients of the Phenobarbital Epilepsy Management Project in a rural area of China: A retrospective study

ABSTRACT

The aim of this study was to explore the compliance of epilepsy patients in the Phenobarbital Epilepsy Management Project in a rural area of China and its influencing factors, so as to provide the basis for further strategies.A retrospective study researching on the compliance of epilepsy patients in the Phenobarbital Epilepsy Management Project of Rural China was conducted. The Nan County, Hunan Province as a typical rural China was selected as the study site. We collected the compliance and other relative factors from 2017 to 2019 though the Phenobarbital Epilepsy Management Project data system.The good compliance patients in the Phenobarbital Epilepsy Management Project in a rural area of China were 98.99% (393/397); only 4 cases had poor compliance. The factors affecting the compliance of epilepsy patients were "adverse reactions of digestive tract symptoms," "how the patient felt physically, mentally, or working and learning ability during this period," and "the ratio of the attack to the previous one."The rate of good compliance among the epilepsy patients in the Phenobarbital Epilepsy Management Project in a rural area of China was high. More attention to education, patients' psychology, and the curative effect of family members may improve the compliance of patients with epilepsy further.

Treatment of epilepsy for people with Alzheimer's disease

BACKGROUND

Any type of seizure can be observed in Alzheimer's disease. Antiepileptic drugs seem to prevent the recurrence of epileptic seizures in most people with Alzheimer's disease. There are pharmacological and non-pharmacological treatments for epilepsy in people with Alzheimer's disease, however there are no current systematic reviews to evaluate the efficacy and tolerability of these treatments. This review aims to investigate these different modalities. This is an updated version of the Cochrane Review previously published in 2018.

OBJECTIVES

To assess the efficacy and tolerability of pharmacological or non-pharmacological interventions for the treatment of epilepsy in people with Alzheimer's disease (including sporadic Alzheimer's disease and dominantly inherited Alzheimer's disease).

SEARCH METHODS

For the latest update, on 3 August 2020 we searched the Cochrane Register of Studies (CRS Web) and MEDLINE (Ovid, 1946 to 31 July 2020). CRS Web includes randomized or quasi-randomized controlled trials from PubMed, EMBASE, ClinicalTrials.gov, the World Health Organization International Clinical Trials Registry Platform (ICTRP), the Cochrane Central Register of Controlled Trials (CENTRAL), and the Specialized Registers of Cochrane Review Groups, including Cochrane Epilepsy. In an effort to identify further published, unpublished and ongoing trials, we searched ongoing trials registers, reference lists and relevant conference proceedings; we also contacted trial authors and pharmaceutical companies.

SELECTION CRITERIA

We included randomized and quasi-randomized controlled trials investigating treatment for epilepsy in people with Alzheimer's disease, with the primary outcomes of proportion of participants with seizure freedom and proportion of participants experiencing adverse events.

DATA COLLECTION AND ANALYSIS

Two review authors independently screened the titles and abstracts of identified records, selected studies for inclusion, extracted data, cross-checked the data for accuracy and assessed the methodological quality. We performed no meta-analyses due to there being limited available data.

MAIN RESULTS

We included one randomized controlled trial (RCT) on pharmacological interventions; the trial included 95 participants. No studies were found for non-pharmacological interventions. Concerning the proportion of participants with seizure freedom, no significant differences were found for the comparisons of levetiracetam versus lamotrigine (RR) 1.20, 95% CI 0.53 to 2.71; 67 participants; very low-certainty evidence), levetiracetam versus phenobarbital (RR 1.01, 95% CI 0.47 to 2.19; 66 participants; very low-certainty evidence), or lamotrigine versus phenobarbital (RR 0.84, 95% CI 0.35 to 2.02; 57 participants; very low-certainty evidence). It seemed that levetiracetam could improve cognition and lamotrigine could relieve depression, while phenobarbital and lamotrigine could worsen cognition, and levetiracetam and phenobarbital could worsen mood. The risk of bias relating to allocation, blinding and selective reporting was unclear. We judged the certainty of the evidence for all outcomes to be very low.

AUTHORS' CONCLUSIONS

This review does not provide sufficient evidence to support levetiracetam, phenobarbital or lamotrigine for the treatment of epilepsy in people with Alzheimer's disease. Regarding efficacy and tolerability, no significant differences were found between levetiracetam, phenobarbital and lamotrigine. Large RCTs with a double-blind, parallel-group design are required to determine the efficacy and tolerability of treatment for epilepsy in people with Alzheimer's disease.

Statewide Emergency Medical Services Protocols for Status Epilepticus Management

Although seizures are common in prehospital settings, standardized emergency medical services (EMS) treatment algorithms do not exist nationally. We examined nationwide variability in status epilepticus treatment by analyzing 33 publicly available statewide EMS protocols. All adult protocols recommend intravenous benzodiazepines (midazolam, n = 33; lorazepam, n = 23; diazepam, n = 24), 30 recommend intramuscular benzodiazepines (midazolam, n = 30; lorazepam, n = 8; diazepam, n = 3), and 27 recommend intranasal benzodiazepines (midazolam, n = 27; lorazepam, n = 3); pediatric protocols also frequently recommend rectal diazepam (n = 14). Recommended dosages vary widely, and first- and second-line agents are designated in only 18 and 2 states, respectively. Given this degree of variability, standardized national EMS guidelines are needed. ANN NEUROL 2021;89:604-609.

Effects of the NKCC1 inhibitors bumetanide, azosemide, and torasemide alone or in combination with phenobarbital on seizure threshold in epileptic and nonepileptic mice

The sodium-potassium-chloride (Na-K-Cl) cotransporter NKCC1 is found in the plasma membrane of a wide variety of cell types, including neurons, glia and endothelial cells in the brain. Increased expression of neuronal NKCC1 has been implicated in several brain disorders, including neonatal seizures and epilepsy. The loop diuretic and NKCC inhibitor bumetanide has been evaluated as an antiseizure agent alone or together with approved antiseizure drugs such as phenobarbital (PB) in pre-clinical and clinical studies with varying results. The equivocal efficacy of bumetanide may be a result of its poor brain penetration. We recently reported that the loop diuretic azosemide is more potent to inhibit NKCC1 than bumetanide. In contrast to bumetanide, azosemide is not acidic, which should favor its brain penetration. Thus, azosemide may be a promising alternative to bumetanide for treatment of brain disorders such as epilepsy. In the present study, we determined the effect of azosemide and bumetanide on seizure threshold in adult epileptic mice. A structurally related non-acidic loop diuretic, torasemide, which also blocks NKCC1, was included in the experiments. The drug effects were assessed by determing the maximal electroshock seizure threshold (MEST) in epileptic vs. nonepileptic mice. Epilepsy was induced by pilocarpine, which was shown to produce long-lasting increases in NKCC1 in the hippocampus, whereas MEST did not alter NKCC1 mRNA in this region. None of the three loop diuretics increased MEST or the effect of PB on MEST in nonepileptic mice. In epileptic mice, all three diuretics significantly increased PB's seizure threshold increasing efficacy, but the effect was variable upon repeated MEST determinations and not correlated with the drugs' diuretic potency. These data may indicate that inhibition of NKCC1 by loop diuretics is not an effective means of increasing seizure threshold in adult epilepsy.

Sex differences in vascular reactivity in mesenteric arteries from a mouse model of acute intermittent porphyria

BACKGROUND AND AIMS

Acute intermittent porphyria (AIP) results from a partial deficiency of porphobilinogen deaminase (PBGD). Symptomatic AIP patients, most of whom are women, experience acute attacks characterized by severe abdominal pain and abrupt increases in blood pressure. Here, we characterized the reactivity of mesenteric arteries from male and female AIP mice with ~30% of normal PBGD activity and wild type C57BL/6 mice.

METHODS

An acute porphyric attack was induced in AIP mice by treatment with phenobarbital. Vascular responses to K⁺, phenylephrine (PE), acetylcholine (ACh), and hemin were determined (Wire Multi Myograph).

RESULTS

Maximal contraction to PE was increased in arteries from male and female AIP mice (p < .05) during an induced attack of acute porphyria. Female AIP arteries had increased sensitivity to PE (p < .05) even after nitric oxide (NO) blockade with N_ω-nitro-L-arginine methyl ester (L-NAME) (p < .05). Maximal relaxation to ACh was similar in males and females with lower sensitivity in female AIP arteries (p < .05). Hemin induced greater relaxation in AIP arteries in both males and females (p < .05).

SUMMARY/CONCLUSIONS

Sex differences in this AIP mouse model include a pro-contractile response in females. These alterations may contribute to the increased blood pressure during an acute attack and provide a novel mechanism of action whereby heme ameliorates the attacks.

Murine models of the human porphyrias: Contributions toward understanding disease pathogenesis and the development of new therapies

Mouse models of the human porphyrias have proven useful for investigations of disease pathogenesis and to facilitate the development of new therapeutic approaches. To date, mouse models have been generated for all major porphyrias, with the exception of X-linked protoporphyria (XLP) and the ultra rare 5-aminolevulinic acid dehydratase deficient porphyria (ADP). Mouse models have been generated for the three autosomal dominant acute hepatic porphyrias, acute intermittent porphyria (AIP), hereditary coproporphyria (HCP), and variegate porphyria (VP). The AIP mice, in particular, provide a useful investigative model as they have been shown to have acute biochemical attacks when induced with the prototypic porphyrinogenic drug, phenobarbital. In addition to providing important insights into the disease pathogenesis of the neurological impairment in AIP, these mice have been valuable for preclinical evaluation of liver-targeted gene therapy and RNAi-mediated approaches. Mice with severe HMBS deficiency, which clinically and biochemically mimic the early-onset homozygous dominant AIP (HD-AIP) patients, have been generated and were used to elucidate the striking phenotypic differences between AIP and HD-AIP. Mice modeling the hepatocutaneous porphyria, porphyria cutanea tarda (PCT), made possible the identification of the iron-dependent inhibitory mechanism of uroporphyrinogen decarboxylase (UROD) that leads to symptomatic PCT. Mouse models for the two autosomal recessive erythropoietic porphyrias, congenital erythropoietic porphyria (CEP) and erythropoeitic protoporphyria (EPP), recapitulate many of the clinical and biochemical features of the severe human diseases and have been particularly useful for evaluation of bone marrow transplantation and hematopoietic stem cell (HSC)-based gene therapy approaches. The EPP mice have also provided valuable insights into the underlying pathogenesis of EPP-induced liver damage and anemia.

Computational disease model of phenobarbital-induced acute attacks in an acute intermittent porphyria mouse model

INTRODUCTION

Acute intermittent porphyria (AIP) is characterized by hepatic over-production of the heme precursors when aminolevulinic acid (ALA)-synthase 1 is induced by endogenous or environmental factors. The aim of this study was to develop a semi-mechanistic computational model to characterize urine accumulation of heme precursors during acute attacks based on experimental pharmacodynamics data and support the development of new therapeutic strategies.

METHODS

Male AIP mice received recurrent phenobarbital challenge starting on days 1, 9, 16 and 30. 24-h urine excretion of ALA, porphobilinogen (PBG) and porphyrins from challenges D1, D9 and D30 constituted the training data set to build the mechanistic model using the population approach. In a second study, porphyrin and porphyrin precursor excretion from challenge D16 were used as a validation data set.

RESULTS

The computational model presented the following features: (i) urinary excretion of ALA, PBG and porphyrins was governed by unmeasured circulating heme precursor amounts, (ii) the circulating amounts of ALA and PBG were the precursors of circulating amounts of PBG and porphyrins, respectively, and (iii) the phenobarbital effect linearly increased the synthesis of circulating ALA and PBG levels. The model displayed good parameter precision (coefficient of variation below 32% in all parameters), and adequately described the experimental data. Finally, a theoretical hemin effect was implemented to illustrate the applicability of the model to dosage optimization in drug therapies.

CONCLUSIONS

A semi-mechanistic disease model was successfully developed to describe the temporal evolution of urinary heme precursor excretion during recurrent biochemical-induced acute attacks in AIP mice. This model represents the first computational approach to explore and optimize current and new therapies.

Characterization of the hepatic transcriptome following phenobarbital induction in mice with AIP

Acute Intermittent Porphyria (AIP), an autosomal dominant hepatic disorder, results from hydroxymethylbilane synthase (HMBS) mutations that decrease the encoded enzymatic activity, thereby predisposing patients to life-threatening acute neurovisceral attacks. The ~1% penetrance of AIP suggests that other genetic factors modulate the onset and severity of the acute attacks. Here, we characterized the hepatic transcriptomic response to phenobarbital (PB) administration in AIP mice, which mimics the biochemical attacks of AIP. At baseline, the mRNA profiles of 14,138 hepatic genes prior to treatment were remarkably similar between AIP and the congenic wild-type (WT) mice. After PB treatment (~120 mg/kg x 3d), 1347 and 1120 genes in AIP mice and 422 and 404 genes in WT mice were uniquely up- and down-regulated, respectively, at a False Discovery Rate < 0.05. As expected, the ALAS1 expression increased 4.5-fold and 15.9-fold in the WT and AIP mice, respectively. ALA-dehydrogenase also was induced ~1.7-fold in PB-induced AIP mice, but was unchanged in PB-induced WT mice. There was no statistically significant difference in the overall expression of 155 hepatic cytochrome P450 enzymes, although Cyp2c40, Cyp2c68, Cyp2c69, Mgst3 were upregulated only in PB-induced AIP mice (>1.9-fold) and Cyp21a1 was upregulated only in PB-induced WT mice (>9-fold). Notably, the genes differentially expressed in induced AIP mice were enriched in circadian rhythm, mitochondria biogenesis and electron transport, suggesting these pathways were involved in AIP mice responding to PB treatment. These results advance our understanding of the hepatic metabolic changes in PB-induced AIP mice and have implications in the pathogenesis of AIP acute attacks.

New derivative of 1,2,4-triazole-3-thione (TP427) potentiates the anticonvulsant action of valproate, but not that of carbamazepine, phenytoin or phenobarbital in the mouse tonic-clonic seizure model

BACKGROUND

To assess the effects of 5-(3-chlorobenzyl)-4-hexyl-2,4-dihydro-3H-1,2,4-triazole-3-thione (TP427) on the protective anticonvulsant action of four classical antiepileptic drugs (carbamazepine, phenobarbital, phenytoin and valproate) in the tonic-clonic seizure model in mice, an isobolographic transformation of data was used.

METHODS

Electrically-induced tonic-clonic seizures were experimentally evoked in adult male albino Swiss mice. The anticonvulsant effects of TP427, when used singly, were determined by the calculation of the threshold increasing the dose by 20% (TID₂₀ value). The influence of TP427 on the anticonvulsant potency of four various classical antiepileptic drugs was determined with a subthreshold method. Types of interactions between drugs were determined using the isobolographic transformation of data. Additionally, total brain antiepileptic drug concentrations were measured.

RESULTS

TP427, when administered separately, significantly increased the threshold for electroconvulsions. The experimentally determined TID₂₀ value for TP427 was 11.71 mg/kg. Moreover, TP427 (10 mg/kg) significantly increased the anticonvulsant activity of valproate (p <  0.01), but not that of carbamazepine, phenobarbital or phenytoin in the mouse tonic-clonic seizure model. Isobolographic transformation of data confirmed that the interaction between TP427 and valproate was synergistic. Pharmacokinetic study revealed that TP427 increased total brain valproate concentrations, and had no impact on total brain concentrations of carbamazepine, phenobarbital or phenytoin in mice.

CONCLUSION

The synergistic interaction between TP427 and valproate in the mouse tonic-clonic seizure model might occur favorable for epilepsy patients in future. The combinations of TP427 with carbamazepine, phenobarbital and phenytoin were additive in the mouse tonic-clonic seizure model and also deserves clinical attention.

Treatment of epilepsy for people with Alzheimer's disease

BACKGROUND

Any type of seizure can be observed in Alzheimer's disease (AD). Antiepileptic drugs seem to prevent the recurrence of epileptic seizures in most people with AD. There are pharmacological and non-pharmacological treatments for epilepsy in people with AD. There are no current systematic reviews to evaluate the efficacy and tolerability of these treatments; this review aims to review those different modalities. This is an updated version of the original Cochrane Review published in Issue 11, 2016.

OBJECTIVES

To assess the efficacy and tolerability of pharmacological or non-pharmacological interventions for the treatment of epilepsy in people with AD (including sporadic AD and dominantly inherited AD).

SEARCH METHODS

For the latest update, on 10 July 2018 we searched the Cochrane Register of Studies (CRS Web), which includes the Cochrane Epilepsy Group's Specialized Register and the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE (Ovid 1946- ), ClinicalTrials.gov, and the WHO International Clinical Trials Registry Platform (ICTRP). In an effort to identify further published, unpublished and ongoing trials, we searched ongoing trials registers, reference lists and relevant conference proceedings, and contacted authors and pharmaceutical companies.

SELECTION CRITERIA

We included randomized and quasi-randomized controlled trials investigating treatment for epilepsy in people with AD, with the outcomes of proportion of participants with seizure freedom or proportion of participants experiencing adverse events.

DATA COLLECTION AND ANALYSIS

Two review authors independently screened the titles and abstracts of identified records, selected studies for inclusion, extracted data, cross-checked the data for accuracy and assessed the methodological quality. We performed no meta-analyses due to the limited available data.

MAIN RESULTS

We included one randomized controlled trial on pharmacological interventions with 95 participants. No studies were found for non-pharmacological interventions. Concerning the proportion of participants with seizure freedom, no significant differences were found for the comparisons of levetiracetam (LEV) versus lamotrigine (LTG) (risk ratio (RR) 1.20, 95% confidence interval (CI) 0.53 to 2.71), LEV versus phenobarbital (PB) (RR 1.01, 95% CI 0.47 to 2.19), or LTG versus PB (RR 0.84, 95% CI 0.35 to 2.02). It seemed that LEV could improve cognition and LTG could relieve depression, while PB and LTG could worsen cognition, and LEV and PB could worsen mood. Unclear risk of bias was found in allocation, blinding and selective reporting. We judged the quality of the evidence to be very low.

AUTHORS' CONCLUSIONS

This review does not provide sufficient evidence to support LEV, PB or LTG for the treatment of epilepsy in people with AD. Regarding efficacy and tolerability, no significant differences were found between LEV, PB and LTG. Large randomized controlled trials with a double-blind, parallel-group design are required to determine the efficacy and tolerability of treatment for epilepsy in people with AD.

Compatibility of Baclofen, Carvedilol, Hydrochlorothiazide, Mercaptopurine, Methadone Hydrochloride, Oseltamivir Phosphate, Phenobarbital, Propranolol Hydrochloride, Pyrazinamide, Sotalol Hydrochloride, Spironolactone, Tacrolimus Monohydrate, Ursodeoxycholic Acid, and Vancomycin Hydrochloride Oral Suspensions Compounded with SyrSpend SF pH4

Compounded liquid medication is frequently required in children to allow easy dose adjustment and overcome swallowing difficulties. The objective of this study was to evaluate the stability of oral suspensions compounded with SyrSpend SF PH4 and the commonly used active pharmaceutical ingredients baclofen 2.0 mg/mL, carvedilol 5.0 mg/mL, hydrochlorothiazide 2.0 mg/mL, mercaptopurine 10.0 mg/mL, methadone hydrochloride 10.0 mg/mL, oseltamivir phosphate 6.0 mg/mL, phenobarbital 9.0 mg/mL and 15.0 mg/mL, propranolol hydrochloride 0.5 mg/mL and 5.0 mg/mL, pyrazinamide 100.0 mg/mL, spironolactone 2.0 mg/mL and 2.5 mg/mL, sotalol hydrochloride 5.0 mg/mL, tacrolimus monohydrate 0.5 mg/mL, ursodeoxycholic acid 20.0 mg/mL, and vancomycin hydrochloride 25.0 mg/mL. Suspensions were compounded with raw powders, except for mercaptopurine, pyrazinamide, and sotalol hydrochloride, which were made from commercial tablets. Stability was assessed by measuring the percentage recovery at 0 (baseline), 60 days, and 90 days after compounding for suspensions made with raw powders, which were stored at 2ÅãC to 8ÅãC. The stability of tablets, which were stored at 2ÅãC to 8ÅãC and 20ÅãC to 25ÅãC, was assessed by measuring the percentage recovery at 0 (baseline), 7 days, 14 days, 30 days, 60 days, and 90 days. Active pharmaceutical ingredients quantification was performed by ultraviolet high-performance liquid chromatography via a stability-indicating method. Given the percentage of recovery of the active pharmaceutical ingredients within the suspensions, the beyond-use date of the final products (active pharmaceutical ingredients + vehicle) was at least 90 days for all suspensions in the conditions tested. This suggests that SyrSpend SF PH4 is suitable for compounding active pharmaceutical ingredients from different pharmacological classes.

Treatment of Alcohol Withdrawal Syndrome: Phenobarbital vs CIWA-Ar Protocol

BACKGROUND

Benzodiazepine-based therapy for alcohol withdrawal is associated with agitation and respiratory depression. Treatment can be complicated by a need for adjunctive therapy to control these symptoms and in patients requiring mechanical ventilation. Strong evidence for the effectiveness of alternative treatment modalities is lacking, despite the availability of promising pharmacological agents such as phenobarbital.

OBJECTIVE

To compare the standard of care for the treatment of alcohol withdrawal-a symptom-triggered benzodiazepine protocol used in conjunction with the revised Clinical Institute Withdrawal Assessment of Alcohol (CIWA-Ar) scale-with a phenobarbital protocol.

METHODS

Retrospective cohort study conducted from January 2016 through June 2017 at a 42-bed medical intensive care unit in a private teaching hospital in Nashville, Tennessee. The primary outcome was intensive care unit length of stay. Secondary outcomes included hospital length of stay, incidence of invasive mechanical ventilation, and use of adjunctive pharmacotherapy.

RESULTS

Patients who received phenobarbital had significantly shorter stays in the intensive care unit than did those who received therapy based on the CIWA-Ar scale (mean [SD], 2.4 [1.5] vs 4.4 [3.9] days; P < .001). Those who received phenobarbital also had significantly shorter hospital stays (4.3 [3.4] vs 6.9 [6.6] days; P = .004). The incidence of invasive mechanical ventilation was lower in the phenobarbital group (1 [2%] vs 14 [23%] patients; P < .001), as was use of adjunctive agents for symptom control, including dexmedetomidine (4 [7%] vs 17 [28%] patients; P = .002).

CONCLUSION

A phenobarbital protocol for the treatment of alcohol withdrawal is an effective alternative to the standard-of-care protocol of symptom-triggered benzodiazepine therapy.

A Randomized Controlled Trial of Phenobarbital and Levetiracetam in Childhood Epilepsy

Levetiracetam has been introduced for the control of seizures besides phenobarbital as monotherapy in children with epilepsy. This study was aimed to compare the effectiveness of these two drugs for the control of seizures in epilepsy. This randomized controlled trial was done to assess the efficacy and tolerability of levetiracetam compared to phenobarbital in childhood epilepsy and was conducted in Institute of Pediatric Neurodisorder and Autism (IPNA), Bangabandhu Sheikh Mujib Medical University (BSMMU), Dhaka, Bangladesh among children between 1 month to 15 years who were diagnosed as cases of epilepsy (idiopathic focal, generalized, focal with secondary generalization) according to ILAE to assess the effect of Levetiracetam (n=50) and Phenobarbital (n=68) from May 2015 to July 2016. The children were followed up for 12 months at 3 months interval to compare the seizure remission and side effects of Levetiracetam and Phenobarbital. The children in levetiracetam group was about 10 months older along with older age of onset of seizure (p=0.02) than those of phenobarbital group (p=0.03 and 0.02 respectively). GTCS was the most common type of seizure in both groups. During 3 months of intervention 55.8% patients of levetiracetam group achieved 50-75% seizure remission compared to 44.2% in phenobarbital group, at 6 months period 75-100% seizure remission observed among 57.4% patients of levetiracetam group compared to 42.6% of phenobarbital group (p=0.06), which continued to increase at 9 months in levetiracetam (n=33, 55.9%) compared to phenobarbital (n=26, 44.1%) and this value is statistically significant (p=0.05). No further improvement observed at 12 months follow up. Behavioral problem was reported among 4 patients of phenobarbital group without any evidence of cognitive deterioration, only 3 patients of levetiracetam experienced irritability, but no children of both group discontinued treatment due to side effects. Levetiracetam mono-therapy is more effective in controlling seizures in focal, generalized and focal with secondary generalization epilepsy compared to phenobarbital with minimum side effects.

Population pharmacokinetics of extended-release levetiracetam in epileptic dogs when administered alone, with phenobarbital or zonisamide

BACKGROUND

Extended-release levetiracetam (LEV-XR) has gained acceptance as an antiepileptic drug in dogs. No studies have evaluated its disposition in dogs with epilepsy.

HYPOTHESIS/OBJECTIVES

To evaluate the pharmacokinetics of LEV-XR in epileptic dogs when administered alone or with phenobarbital or zonisamide.

ANIMALS

Eighteen client-owned dogs on steady-state maintenance treatment with LEV-XR (Group L, n = 6), LEV-XR and phenobarbital (Group LP, n = 6), or LEV-XR and zonisamide (Group LZ, n = 6).

METHODS

Pharmacokinetic study. Blood samples were collected at 0, 2, 4, 8, and 12 hours after LEV-XR was administered with food. Plasma LEV concentrations were determined by high-pressure liquid chromatography. A population pharmacokinetic approach and nonlinear mixed effects modeling were used to analyze the data.

RESULTS

Treatment group accounted for most of the interindividual variation. The LP group had lower CMAX (13.38 μg/mL) compared to the L group (33.01 μg/mL) and LZ group (34.13 μg/mL), lower AUC (134.86 versus 352.95 and 452.76 hours·μg/mL, respectively), and higher CL/F (0.17 versus 0.08 and 0.07 L/kg/hr, respectively). The half-life that defined the terminal slope of the plasma concentration versus time curve (~5 hours) was similar to values previously reported for healthy dogs.

CONCLUSIONS AND CLINICAL IMPORTANCE

Considerable variation exists in the pharmacokinetics of LEV-XR in dogs with epilepsy being treated with a common dose regimen. Concurrent administration of phenobarbital contributed significantly to the variation. Other factors evaluated, including co-administration of zonisamide, were not shown to contribute to the variability. Drug monitoring may be beneficial to determine the most appropriate dose of LEV-XR in individual dogs.

Dose-dependent reversal of KCC2 hypofunction and phenobarbital-resistant neonatal seizures by ANA12

Neonatal seizures have an incidence of 3.5 per 1000 newborns; while hypoxic-ischemic encephalopathy (HIE) accounts for 50-60% of cases, half are resistant to 1st-line anti-seizure drugs such as phenobarbital (PB). Tyrosine receptor kinase B (TrkB) activation following ischemic injury is known to increase neuronal excitability by downregulation of K-Cl co-transporter 2 (KCC2); a neuronal chloride (Cl-) co-transporter. In this study, three graded doses of ANA12, a small-molecule selective TrkB antagonist, were tested in CD1 mice at P7 and P10 following induction of neonatal ischemia by a unilateral carotid ligation. The PB loading dose remained the same in all treatment groups at both ages. Evaluation criteria for the anti-seizure efficacy of ANA12 were: (1) quantitative electroencephalographic (EEG) seizure burden and power, (2) rescue of post-ischemic KCC2 and pKCC2-S940 downregulation and (3) reversal of TrkB pathway activation following ischemia. ANA12 significantly rescued PB resistant seizures in a dose-dependent manner at P7 and improved PB efficacy at P10. Additionally, female pups responded better to lower doses of ANA12 compared to males. ANA12 significantly reversed post-ischemic KCC2 downregulation and TrkB pathway activation at P7 when PB alone was inefficacious. Rescuing KCC2 hypofunction may be critical for preventing emergence of refractory seizures.

Outpatient Pharmacotherapy for Neonatal Abstinence Syndrome

OBJECTIVE

To determine differences in lengths of stay, length of therapy, emergency department (ED) utilization, and hospital readmissions between infants with neonatal abstinence syndrome (NAS) treated exclusively with inpatient pharmacotherapy compared with those discharged on outpatient pharmacotherapy.

STUDY DESIGN

This retrospective cohort study of infants enrolled in the Tennessee Medicaid program used administrative and vital records data from 2009 to 2011. Medical record review was used to confirm cases of NAS and classify treatment type. Negative binomial regression was used to compare length of therapy and ordinal regression was used to determine frequency of ED visits and hospital readmissions.

RESULTS

Among a cohort of 736 patients with confirmed NAS, 72.3% were treated with pharmacotherapy of which approximately one-half (45.5%) were discharged home on outpatient medications. For infants discharged on outpatient pharmacotherapy, initial hospital length of stay was shorter (11 vs 23 days; P < .001) and length of therapy was longer (60 vs 19 days; adjusted incidence rate ratio [aIRR] 2.84, 95%CI 2.31-3.52). After adjusting for potential confounders, infants discharged on outpatient pharmacotherapy had a greater number of ED visits within 6 months of discharge (adjusted odds ratio [aOR] 1.52, 95% CI 1.06-2.17) compared with those treated as inpatients alone.

CONCLUSIONS

Outpatient pharmacotherapy for NAS was associated with higher length of therapy and higher rates of ED utilization when compared with infants treated exclusively as inpatients. Future research should focus on improving the efficiency of NAS management while minimizing postdischarge complications.

Isobolographic additivity among lacosamide, lamotrigine and phenobarbital in a mouse tonic-clonic seizure model

BACKGROUND

Epilepsy is a serious neurological disease affecting about 1% of people worldwide (65 million). Seizures are controllable with antiepileptic drugs (AEDs) in about 70% of epilepsy patients, however, there remains about 30% of patients inadequately medicated with these AEDs, who need a satisfactory control of their seizure attacks. For these patients, one of the treatment options is administration of 2 or 3 AEDs in combination.

OBJECTIVES

To determine the anticonvulsant effects of a combination of 3 selected AEDs (i.e., lacosamide - LCM, lamotrigine - LTG and phenobarbital - PB) at the fixed-ratio of 1:1:1 in a mouse maximal electroshock-induced (tonic-clonic) seizure model by using isobolographic analysis.

MATERIAL AND METHODS

Seizure activity was evoked in adult male albino Swiss mice by a current (sinewave, 25 mA, 500 V, 50 Hz, 0.2 s stimulus duration) delivered via auricular electrodes. Type I isobolographic analysis was used to detect interaction for the 3-drug combination.

RESULTS

With type I isobolographic analysis, the combination of LCM, LTG and PB (at the fixed-ratio of 1:1:1) exerted additive interaction in the mouse maximal electroshock-induced (tonic-clonic) seizure model.

CONCLUSIONS

The combination of LCM with LTG and PB produced additive interaction in the mouse tonicclonic seizure model, despite various molecular mechanisms of action of the tested AEDs.

Preliminary study of the association between the elimination parameters of phenytoin and phenobarbital

BACKGROUND

Therapeutic drug monitoring is essential for both phenytoin and phenobarbital therapy given their narrow therapeutic indexes. Nevertheless, the measurement of either phenytoin or phenobarbital concentrations might not be available in some rural hospitals. Information assisting individualized phenytoin and phenobarbital combination therapy is important. This study's objective was to determine the relationship between the maximum rate of metabolism of phenytoin (Vmax) and phenobarbital clearance (CLPB), which can serve as a guide to individualized drug therapy.

METHODS

Data on phenytoin and phenobarbital concentrations of 19 epileptic patients concurrently receiving both drugs were obtained from medical records. Phenytoin and phenobarbital pharmacokinetic parameters were studied at steady-state conditions. The relationship between the elimination parameters of both drugs was determined using simple linear regression.

RESULTS

A high correlation coefficient between Vmax and CLPB was found [r=0.744; p<0.001 for Vmax (mg/kg/day) vs. CLPB (L/kg/day)]. Such a relatively strong linear relationship between the elimination parameters of both drugs indicates that Vmax might be predicted from CLPB and vice versa.

CONCLUSIONS

Regression equations were established for estimating Vmax from CLPB, and vice versa in patients treated with combination of phenytoin and phenobarbital. These proposed equations can be of use in aiding individualized drug therapy.

Tolerability and Safety of Commonly Used Antiepileptic Drugs in Adolescents and Adults: A Clinician's Overview

This paper discusses the issues surrounding the tolerability and safety of the commonly used antiepileptic drugs (AEDs) in adolescents and adults. The content includes dose-related adverse effects, idiosyncratic reactions, behavioural and psychiatric comorbidities, chronic problems, enzyme induction and teratogenesis. Twenty-one AEDs are discussed in chronological order of their introduction into the UK, starting with phenobarbital and ending with brivaracetam. Wherever possible, advice is given on anticipating, recognising and managing these issues and thereby improving the lives of people with epilepsy, most of whom will need to take one or more of these agents for life. Avoidance of side effects will increase the possibility of achieving and maintaining long-term seizure freedom. Alternatively, adverse events from AEDs will substantially reduce quality of life and often result in higher healthcare costs.

[Benzodiazepines should still be first-line treatment for alcohol withdrawal]

In this review, we summarize the evidence for benzodiazepines and barbiturates as alcohol withdrawal treatment and outline a treatment guideline. A number of randomized controlled trials (RCTs) indicate that benzodiazepine treatment decreases alcohol withdrawal seizures and is safe. For barbiturates, only a few RCTs have been undertaken, and barbiturates were not found to be superior to benzodiazepines. Consequently, we suggest that benzodiazepines should still be first-line treatment for alcohol withdrawal.

Effect of Withholding Phenobarbitone Maintenance in Neonatal Seizures: A Randomized Controlled Trial

OBJECTIVE

To compare the effect of withholding maintenance phenobarbitone on breakthrough seizures.

DESIGN

A double blind randomized controlled trial.

SETTING

Level II neonatal intensive care unit (NICU) of a teaching hospital in Northern India.

PARTICIPANTS

152 term and near term neonates (34 weeks of gestation age) with admission weight ≥2 kg with clinically apparent seizures who received intravenous (IV) loading dose of 20 mg/kg of phenobarbitone.

INTERVENTIONS

After 12 hours of seizure free period of the initial loading dose of phenobarbitone, one group received IV maintenance therapy and other 'no maintenance' (saline as placebo).

MAIN OUTCOME MEASURE

Breakthrough seizures from randomization till discharge.

RESULTS

Baseline variables were comparable in the two groups. Breakthrough seizures occurred in 30 (40%) subjects in placebo group and 24 (31.2%) in phenobarbitone group with RR (95% CI) of 1.28 (0.83-1.97) (P=0.19). Seizure recurrence, re-hospitali-sation, mortality and abnormal neurological assessment until 3 months were comparable in the two groups (P>0.05). Babies in either group with breakthrough seizures were more likely to be neurologically abnormal at 1 month than babies who did not have breakthrough seizures, but this difference decreased by 3 months.

CONCLUSION

In term and near-term neonates, those who respond to loading dose of phenobarbitone after a single seizure episode, withholding of phenobarbitone maintenance may not significantly increase the risk of breakthrough seizures.

dOFV distributions: a new diagnostic for the adequacy of parameter uncertainty in nonlinear mixed-effects models applied to the bootstrap

Knowledge of the uncertainty in model parameters is essential for decision-making in drug development. Contrarily to other aspects of nonlinear mixed effects models (NLMEM), scrutiny towards assumptions around parameter uncertainty is low, and no diagnostic exists to judge whether the estimated uncertainty is appropriate. This work aims at introducing a diagnostic capable of assessing the appropriateness of a given parameter uncertainty distribution. The new diagnostic was applied to case bootstrap examples in order to investigate for which dataset sizes case bootstrap is appropriate for NLMEM. The proposed diagnostic is a plot comparing the distribution of differences in objective function values (dOFV) of the proposed uncertainty distribution to a theoretical Chi square distribution with degrees of freedom equal to the number of estimated model parameters. The uncertainty distribution was deemed appropriate if its dOFV distribution was overlaid with or below the theoretical distribution. The diagnostic was applied to the bootstrap of two real data and two simulated data examples, featuring pharmacokinetic and pharmacodynamic models and datasets of 20–200 individuals with between 2 and 5 observations on average per individual. In the real data examples, the diagnostic indicated that case bootstrap was unsuitable for NLMEM analyses with around 70 individuals. A measure of parameter-specific “effective” sample size was proposed as a potentially better indicator of bootstrap adequacy than overall sample size. In the simulation examples, bootstrap confidence intervals were shown to underestimate inter-individual variability at low sample sizes. The proposed diagnostic proved a relevant tool for assessing the appropriateness of a given parameter uncertainty distribution and as such it should be routinely used.

The effects of co-medications on lamotrigine clearance in Japanese children with epilepsy

PURPOSE

Although it has been reported that some antiepileptic drugs have inducing or inhibiting effects on lamotrigine (LTG) clearance, whether they have the same effects in Asian epilepsy patients as in those in other countries has not been clarified, especially in children. The aim of this study was to determine the effects of co-medications on LTG clearance in Japanese children with epilepsy.

METHODS

A total of 342 routine serum concentration measurements of LTG in 102 Japanese epilepsy patients under 20years of age were reviewed. The dose-corrected concentration (DCC) of LTG was calculated as [concentration]/[dose/(body weight)], and the DCC of LTG was compared by co-medication. The difference in the DCC of LTG was compared between patients with and without valproic acid (VPA) and between those with and without drugs inducing glucuronic acid conjugation (phenytoin (PHT), carbamazepine (CBZ), and phenobarbital (PB)).

RESULTS

The DCC of LTG was significantly higher in patients on VPA and significantly lower in patients on drugs inducing glucuronic acid conjugation than in patients on LTG monotherapy. The DCC of LTG was significantly higher in patients on CBZ than in patients on PHT or PB. There was no correlation between the DCC of LTG and the concentration of VPA or metabolic inducers within the therapeutic range. Other antiepileptic drugs including clobazam, clonazepam, zonisamide, and levetiracetam had little effect on LTG concentration.

CONCLUSION

LTG concentration changes dramatically with concomitant antiepileptic drugs in Japanese children, as previously reported from other countries, and special attention is required. Although the dose of LTG should be adjusted when starting or discontinuing VPA or metabolic inducers, no adjustment is needed when changing the dose of VPA or metabolic inducers in the therapeutic range.

Pharmacokinetics of Phenobarbital in Microenema Via Macy Catheter Versus Suppository

CONTEXT

The oral route is compromised for nearly all patients approaching death. When agitation, seizures, or other intractable symptoms occur, a quick, discreet, comfortable, and effective alternate route for medication delivery that is easy to administer in the home setting is highly desirable.

OBJECTIVES

To characterize the early absorption profile, variability, and comfort of phenobarbital given in microenema suspensions delivered via the Macy Catheter(®) (MC) vs. the same dose given via suppository.

METHODS

This was a randomized, open-label, crossover study comparing the early absorption profile of equal doses of phenobarbital administered rectally in three treatment phases: phenobarbital suppository and two different microenemas with phenobarbital tablets crushed and suspended in 6 mL (MC-6) or 20 mL (MC-20) of tap water.

RESULTS

Mean plasma phenobarbital concentrations at 10 minutes were 12× higher for MC-20 and 8× higher for MC-6 compared to suppository. Concentrations achieved in 30 minutes via MC-20 took almost three hours to achieve with suppository. Mean AUC values were higher for MC-20 and MC-6 (82% and 46%, respectively) vs. suppository (P < 0.05). There was less variability in absorption for MC-20 and MC-6 (1.4- to 1.9-fold difference) compared to a 4.4-fold difference via suppository. MC administrations were reported as "not uncomfortable" compared to suppositories, which were reported as "mildly uncomfortable" (P < 0.05).

CONCLUSION

These results suggest phenobarbital oral tablets crushed and suspended in water and administered via the MC is superior to suppository in delivering the medication reliably and rapidly.

Comparison of the long-term behavioral effects of neonatal exposure to retigabine or phenobarbital in rats

Anticonvulsant drugs, when given during vulnerable periods of brain development, can have long-lasting consequences on nervous system function. In rats, the second postnatal week approximately corresponds to the late third trimester of gestation/early infancy in humans. Exposure to phenobarbital during this period has been associated with deficits in learning and memory, anxiety-like behavior, and social behavior, among other domains. Phenobarbital is the most common anticonvulsant drug used in neonatology. Several other drugs, such as lamotrigine, phenytoin, and clonazepam, have also been reported to trigger behavioral changes. A new generation anticonvulsant drug, retigabine, has not previously been evaluated for long-term effects on behavior. Retigabine acts as an activator of KCNQ channels, a mechanism that is unique among anticonvulsants. Here, we examined the effects retigabine exposure from postnatal day (P)7 to P14 on behavior in adult rats. We compared these effects with those produced by phenobarbital (as a positive control) and saline (as a negative control). Motor behavior was assessed by using the open field and rotarod, anxiety-like behavior by the open field, elevated plus maze, and light-dark transition task, and learning/memory by the passive avoidance task; social interactions were assessed in same-treatment pairs, and nociceptive sensitivity was assessed via the tail-flick assay. Motor behavior was unaltered by exposure to either drug. We found that retigabine exposure and phenobarbital exposure both induced increased anxiety-like behavior in adult animals. Phenobarbital, but not retigabine, exposure impaired learning and memory. These drugs also differed in their effects on social behavior, with retigabine-exposed animals displaying greater social interaction than phenobarbital-exposed animals. These results indicate that neonatal retigabine induces a subset of behavioral alterations previously described for other anticonvulsant drugs and extend our knowledge of drug-induced behavioral teratogenesis to a new mechanism of anticonvulsant action.

Short-Term Effects of Phenobarbitone on Electrographic Seizures in Neonates

BACKGROUND

Phenobarbitone is the most common first-line anti-seizure drug and is effective in approximately 50% of all neonatal seizures.

OBJECTIVE

To describe the response of electrographic seizures to the administration of intravenous phenobarbitone in neonates using seizure burden analysis techniques.

METHODS

Multi-channel conventional EEG, reviewed by experts, was used to determine the electrographic seizure burden in hourly epochs. The maximum seizure burden evaluated 1 h before each phenobarbitone dose (T-1) was compared to seizure burden in periods of increasing duration after each phenobarbitone dose had been administered (T+1, T+2 to seizure offset). Differences were analysed using linear mixed models and summarized as means and 95% CI.

RESULTS

Nineteen neonates had electrographic seizures and met the inclusion criteria for the study. Thirty-one doses were studied. The maximum seizure burden was significantly reduced 1 h after the administration of phenobarbitone (T+1) [-14.0 min/h (95% CI: -19.6, -8.5); p < 0.001]. The percentage reduction was 74% (IQR: 36-100). This reduction was temporary and not significant within 4 h of administrating phenobarbitone. Subgroup analysis showed that only phenobarbitone doses at 20 mg/kg resulted in a significant reduction in the maximum seizure burden from T-1 to T+1 (p = 0.002).

CONCLUSIONS

Phenobarbitone significantly reduced seizures within 1 h of administration as assessed with continuous multi-channel EEG monitoring in neonates. The reduction was not permanent and seizures were likely to return within 4 h of treatment.

Suivi thérapeutique pharmacologique de trois médicaments antiépileptiques: retour sur vingt années d’expérience

Introduction

Le suivi thérapeutique pharmacologique (STP) des médicaments antiépileptiques (MAE) est un outil très utilisé dans la gestion de l'épilepsie. Au Maroc, ce dosage est réalisé au Centre Anti Poison et de Pharmacovigilance du Maroc (CAPM) depuis Avril 1995.

Méthodes

Il s'agit d'une étude rétrospective s'étalant sur 20 ans. Elle concerne le STP du Phénobarbital (PB), de la Carbamazépine (CBZ) et de l'Acide Valproique (AVP).

Résultats

Le STP des 3 MAE représentaient 58,85% de l'ensemble des demandes de STP reçue par le CAPM. Le dosage du PB était classé en première position suivi par celui de la CBZ et enfin par l'AVP. La faible demande de STP au Maroc pouvait être expliquée par le faible nombre de neurologues auquel s'ajoutaient des facteurs sociaux. Grâce à son prix très accessible par les patients, le PB est le MAE le plus prescrit dans notre pays expliquant ainsi la demande élevée de son dosage. Quant aux motifs de STP des 3 MAE, ils étaient essentiellement liés à l'âge, à l'apparition d'effets indésirables, à l'association de MAE ou dans le cas de vérification de l'observance des malades.

Conclusion

Des efforts sont à fournir pour promouvoir l'intérêt du STP des MAE dans la prise en charge de l'épilepsie au Maroc.

A single-blinded phenobarbital-controlled trial of levetiracetam as mono-therapy in dogs with newly diagnosed epilepsy

Treatment of canine epilepsy is problematic. Few antiepileptic drugs have proven efficacy in dogs and undesirable adverse effects and pharmacoresistance are not uncommon. Consequently, the need for investigation of alternative treatment options is ongoing. The objective of this study was to investigate the efficacy and tolerability of levetiracetam as mono-therapy in dogs with idiopathic epilepsy. The study used a prospective single-blinded parallel group design. Twelve client-owned dogs were included and were randomised to treatment with levetiracetam (30 mg/kg/day or 60 mg/kg/day divided into three daily dosages) or phenobarbital (4 mg/kg/day divided twice daily). Control visits were at days 30, 60 and then every 3 months for up to 1 year. Two or more seizures within 3 months led to an increase in drug dosage (levetiracetam: 10 mg/kg/day, phenobarbital: 1 mg/kg/day). Five of six levetiracetam treated dogs and one of six phenobarbital treated dogs withdrew from the study within 2-5 months due to insufficient seizure control. In the levetiracetam treated dogs there was no significant difference in the monthly number of seizures before and after treatment, whereas in the phenobarbital treated dogs there were significantly (P = 0.013) fewer seizures after treatment. Five phenobarbital treated dogs were classified as true responders (≥50% reduction in seizures/month) whereas none of the levetiracetam treated dogs fulfilled this criterion. Adverse effects were reported in both groups but were more frequent in the phenobarbital group. In this study levetiracetam was well tolerated but was not effective at the given doses as mono-therapy in dogs with idiopathic epilepsy.

Acute TrkB inhibition rescues phenobarbital-resistant seizures in a mouse model of neonatal ischemia

Neonatal seizures are commonly associated with hypoxic-ischemic encephalopathy. Phenobarbital (PB) resistance is common and poses a serious challenge in clinical management. Using a newly characterized neonatal mouse model of ischemic seizures, this study investigated a novel strategy for rescuing PB resistance. A small-molecule TrkB antagonist, ANA12, used to selectively and transiently block post-ischemic BDNF-TrkB signaling in vivo, determined whether rescuing TrkB-mediated post-ischemic degradation of the K(+)-Cl(-) co-transporter (KCC2) rescued PB-resistant seizures. The anti-seizure efficacy of ANA12 + PB was quantified by (i) electrographic seizure burden using acute continuous video-electroencephalograms and (ii) post-treatment expression levels of KCC2 and NKCC1 using Western blot analysis in postnatal day (P)7 and P10 CD1 pups with unilateral carotid ligation. ANA12 significantly rescued PB-resistant seizures at P7 and improved PB efficacy at P10. A single dose of ANA12 + PB prevented the post-ischemic degradation of KCC2 for up to 24 h. As anticipated, ANA12 by itself had no anti-seizure properties and was unable to prevent KCC2 degradation at 24 h without follow-on PB. This indicates that unsubdued seizures can independently lead to KCC2 degradation via non-TrkB-dependent pathways. This study, for the first time as a proof-of-concept, reports the potential therapeutic value of KCC2 modulation for the management of PB-resistant seizures in neonates. Future investigations are required to establish the mechanistic link between ANA12 and the prevention of KCC2 degradation.

Kaneuron: an oral solution of phenobarbital with dangerous packaging

The syringe with dual graduations has been eliminated following cases of overdose in children, but there is still no child-proof cap.

[A case of acute encephalitis with refractory repetitive partial seizures successfully controlled by very-high-dose phenobarbital therapy found in a boy]

We experienced a case of acute encephalitis with refractory, repetitive partial seizures (AERRPS) found in an 8-year-old boy. Convulsive status epilepticus developed at the onset, which was intractable to the treatment with intravenous thiopental sodium even at the maximum dose of 9 mg/kg/hr. Since the adverse effect developed, thiopental sodium was discontinued. Phenobarbital (PB) was administrated at a very high daily dose up to 80 mg/kg, reaching serum trough level of 250 μg/ml, which was markedly effective to the treatment. Because seizures reappeared during tapering the dosage of PB, potassium bromide (KBr) at a daily dose of 80 mg/kg was additionally administrated. PB was successfully tapered into a daily dose of 20 mg/kg with a trough serum level around 80 μg/ml. He recovered in motor functions, but had disturbance of memory and apneic seizures. A very-high-dose PB therapy in an early period may be helpful for the treatment of intractable convulsive status epilepticus.

High phenobarbital clearance during continuous renal replacement therapy: a case report and pharmacokinetic analysis

Phenobarbital is an old antiepileptic drug used in severe epilepsy. Despite this, little is written about the need for dose adjustments in renal replacement therapy. Most sources recommend a moderately increased dose guided by therapeutic drug monitoring.A 14 year old boy with nonketotic hyperglycinemia, a rare inborn error of metabolism, characterized by high levels of glycine, epilepsy, spasticity, and cognitive impairment, was admitted to the emergency department with respiratory failure after a few days of fever and cough. The boy was unconscious at admittance and had acute renal and hepatic failure.Due to the acute respiratory infection, hypoxic hepatic and renal failure occurred and the patient had a status epilepticus.The patient was intubated and mechanically ventilated. Continuous renal replacement therapy was initiated. Despite increased phenobarbital doses, therapeutic levels were not reached until the dose was increased to 500 mg twice daily. Therapeutic drug monitoring was performed in plasma and dialysate. Calculations revealed that phenobarbital was almost freely dialyzed.Correct dosing of drugs in patients on renal replacement therapy may need a multidisciplinary approach and guidance by therapeutic drug monitoring.

Adverse neurodevelopmental outcomes after exposure to phenobarbital and levetiracetam for the treatment of neonatal seizures

OBJECTIVE

Compare neurodevelopment after levetiracetam (LEV) and phenobarbital (PB) for neonatal seizures.

STUDY DESIGN

Retrospective study of infants who received antiepileptic drugs (AEDs) for neonatal seizures. Effect of cumulative exposure to LEV and PB on outcomes of death, cerebral palsy (CP) and Bayley Scales of Infant Development (BSID) scores were evaluated at 24 months corrected age. Analyses were adjusted for number of electrographic seizures and gestational age.

RESULT

In 280 infants with comparable seizure etiology and cranial imaging results, increased exposure to PB was associated with worse BSID cognitive and motor scores (8.1- and 9-point decrease per 100 mg kg(-1); P=0.01). The effect was less with LEV (2.2- and 2.6-point decrease per 300 mg kg(-1) LEV (P=0.01)). CP probability increased by 2.3-fold per 100 mg kg(-1) PB and was not associated with increasing LEV.

CONCLUSION

Increased exposure to PB is associated with worse neurodevelopmental outcomes than LEV. Prospective studies of outcomes of neonatal exposure to AEDs are essential.

Phenobarbital induces alterations in the proteome of hepatocytes and mesenchymal cells of rat livers

Preceding studies on the mode of action of non-genotoxic hepatocarcinogens (NGCs) have concentrated on alterations induced in hepatocytes (HCs). A potential role of non-parenchymal liver cells (NPCs) in NGC-driven hepatocarcinogenesis has been largely neglected so far. The aim of this study is to characterize NGC-induced alterations in the proteome profiles of HCs as well as NPCs. We chose the prototypic NGC phenobarbital (PB) which was applied to male rats for a period of 14 days. The livers of PB-treated rats were perfused by collagenase and the cell suspensions obtained were subjected to density gradient centrifugation to separate HCs from NPCs. In addition, HCs and NPC isolated from untreated animals were treated with PB in vitro. Proteome profiling was done by CHIP-HPLC and ion trap mass spectrometry. Proteome analyses of the in vivo experiments showed many of the PB effects previously described in HCs by other methods, e.g. induction of phase I and phase II drug metabolising enzymes. In NPCs proteins related to inflammation and immune regulation such as PAI-1 and S100-A10, ADP-ribosyl cyclase 1 and to cell migration such as kinesin-1 heavy chain, myosin regulatory light chain RLC-A and dihydropyrimidinase-related protein 1 were found to be induced, indicating major PB effects on these cells. Remarkably, in vitro treatment of HCs and NPCs with PB hardly reproduced the proteome alterations observed in vivo, indicating differences of NGC induced responses of cells at culture conditions compared to the intact organism. To conclude, the present study clearly demonstrated that PB induces proteome alterations not only in HCs but also in NPCs. Thus, any profound molecular understanding on the mode of action of NGCs has to consider effects on cells of the hepatic mesenchyme.

[Efficacy of intravenous phenobarbital treatment for status epilepticus]

PURPOSE

Intravenous phenobarbital (IV-PB) therapy was launched in Japan in October 2008. We retrospectively investigated its efficacy and tolerability in patients with status epilepticus.

METHODS

Forty-three consecutive patients received IV-PB for status epilepticus between June 2009 and April 2011. Among them, 39 patients had underlying diseases, which included acute diseases in 19 patients and chronic conditions in 20 patients. Although 18 patients had been taking antiepileptic drugs (AEDs) before the occurrence of status epilepticus, the blood AED concentrations in 8 patients was below the therapeutic levels. Before the administration of IV-PB, 39 patients were treated with intravenous benzodiazepine, 17 patients were treated with intravenous phenytoin, and 15 patients with intravenous infusion of lidocaine.

RESULTS

The initial doses of IV-PB ranged from 125 to 1,250 mg (1.9-20.0 mg/kg). Additional doses of IV-PB were required in 12 patients. Seizures were controlled in 35 patients (81%) after IV-PB administration. Cessation of status epilepticus was attained in 24 patients after the initial dose and in 11 patients after additional doses. There were no serious adverse effects, although respiratory suppression was observed in 3 patients and drug eruption was observed in 1 patient.

CONCLUSION

IV-PB is relatively safe and effective for controlling status epilepticus. If the first dose is not effective, additional doses are required up to the recommended maximum dose.

Bumetanide enhances phenobarbital efficacy in a rat model of hypoxic neonatal seizures

Neonatal seizures can be refractory to conventional anticonvulsants, and this may in part be due to a developmental increase in expression of the neuronal Na(+)-K(+)-2 Cl(-) cotransporter, NKCC1, and consequent paradoxical excitatory actions of GABAA receptors in the perinatal period. The most common cause of neonatal seizures is hypoxic encephalopathy, and here we show in an established model of neonatal hypoxia-induced seizures that the NKCC1 inhibitor, bumetanide, in combination with phenobarbital is significantly more effective than phenobarbital alone. A sensitive mass spectrometry assay revealed that bumetanide concentrations in serum and brain were dose-dependent, and the expression of NKCC1 protein transiently increased in cortex and hippocampus after hypoxic seizures. Importantly, the low doses of phenobarbital and bumetanide used in the study did not increase constitutive apoptosis, alone or in combination. Perforated patch clamp recordings from ex vivo hippocampal slices removed following seizures revealed that phenobarbital and bumetanide largely reversed seizure-induced changes in EGABA. Taken together, these data provide preclinical support for clinical trials of bumetanide in human neonates at risk for hypoxic encephalopathy and seizures.

[Intravenous injection of phenobarbital for benign convulsions with mild gastroenteritis]

OBJECTIVE

We investigated the effectiveness of intravenous injection of phenobarbital (PB) in patients referred to Himeji Red Cross Hospital, Hyogo, Japan, with benign convulsions with mild gastroenteritis (CwG) between November 2009 and June 2011.

METHODS

The patients who had a single seizure at the time of consultation were, in principle, followed without any treatment, and those with repeated seizures were treated with intravenous injection of 10 mg/kg PB.

RESULTS

During the study, 24 of 33 patients with CwG were administered PB intravenously. PB was administered after a single seizure in one patient, and the remainder were treated after 2-7 seizures, no patient had repeated seizures. The side effects were temporary and mild, although somnolence was seen in five patients, and two also showed staggering.

CONCLUSIONS

It was considered that intravenous injection of PB was effective for CwG. Intravenous injection of PB should be given to patients with CwG, regardless of whether they have vomiting and diarrhea.

Brain anticonvulsant protection of mice given chronic carbamazepine under various fatty acid and magnesium diet conditions

The anticonvulsant and mood stabilizer drug carbamazepine (CBZ) was evaluated for anti-seizure activity after drug pretreatment of young weaning mice given various oil-based diets. These diets had various mono-(MUFA) and poly-(PUFA) unsaturated fatty acid contents, were associated or not with magnesium deprivation, and were given over the entire experimental period (34 days). The diets included a commercial and three purified synthetic diets (n-6 PUFA, n-3 PUFA and MUFA-based chows containing 5% corn/sunflower oils 1:3, 5% rapeseed oil and 5% high oleic acid sunflower oil/sunflower oil 7:3, respectively). A 10-days CBZ treatment (50 mg/kg/day fragmented in two daily intraperitoneal injections of 25 mg/kg) was given 20 days after initiating diet administration and evaluations of mice was performed 4 days after arrest of CBZ in various seizure tests. In these conditions, CBZ pretreatment still exhibited anticonvulsant protection especially in magnesium-deficient animals. Ethosuximide (ESM)-like profiles under MUFA and n-3 PUFA diets and unusual GABA(A)ergic profile under n-6 PUFA diet in magnesium-deficiency dependent audiogenic seizures (MDDAS) test as well as protection against NMDA-induced seizures in all lipid (n-3 PUFA>MUFA and n-6 PUFA) diet conditions were observed in CBZ-pretreated mice. By highlighting ESM-like and anti-NMDA mechanisms previously induced by an n-3 PUFA diet, present CBZ anticonvulsant properties suggest brain protective targets common to CBZ and n-3 PUFAs.

Phenobarbitone Population Pharmacokinetics from Routine Clinical Data: Role of Patient Characteristics for Estimating Dosing Regimens

Routine clinical pharmacokinetic data collected from patients receiving phenobarbitone have been analysed to evaluate the role of patient characteristics for estimating dosing regimens. The data were analysed using NONMEM, a computer program designed for population pharmacokinetic analysis that allows pooling of data. The pharmacokinetic model of phenobarbitone was described using a one-compartment steady-state model. The effect of a variety of developmental and demographic factors on clearance was investigated. NONMEM estimates indicated a nonlinear function of total body weight as the optimum adjustment of phenobarbitone clearance. Concomitant administration of phenobarbitone and other antiepileptic drugs showed a decrease of phenobarbitone clearance in young children. The dosing method based on clearance values obtained by NONMEM analysis allowed the prediction of the steady-state concentration as a function of maintenance dose with acceptable error for therapeutic drug monitoring.

Dupuytren's contracture as result of prolonged administration of phenobarbital

Dupuytren's disease is a fibroproliferative condition involving the superficial palmar fascia, leading to a progressive and irreversible flexion of the fingers. In literature, there are different opinions regarding the phenobarbital, a common antiepileptic drug, and its effective role in the genesis and development of Dupuytren's disease. In this retrospective investigation the association between phenobarbital and Dupuytren's contracture is discussed. Three patients in treatment with phenobarbital who had no others significant risk factors for Dupuytren's contracture were included in this study. The disease occurred after one to four years of drug therapy, at dosage of 100 mg/day. After surgery, Dupuytren's disease showed different evolutions in relation to dosage and type of antiepileptic drug used. Phenobarbital causes a dose and time-dipendent profibrotic effect. A clinical regression was observed when phenobarbital was substituted by carbamazepine, maintaining the same dosage (100 mg/day). This data confirms that not all the antiepileptic drugs are implicated in palmar fibrosis, and suggests that, according to the efficacy and adverse effects, the administration of benzodiazepine reduces the risk of Dupuytren's recurrence.

Synthetic cannabinoid WIN 55,212-2 mesylate enhances the protective action of four classical antiepileptic drugs against maximal electroshock-induced seizures in mice

The aim of this study was to determine the effect of WIN 55,212-2 mesylate (WIN--a non-selective cannabinoid CB1 and CB2 receptor agonist) on the protective action of four classical antiepileptic drugs (carbamazepine, phenytoin, phenobarbital, and valproate) in the mouse maximal electroshock seizure (MES) model. The results indicate that WIN (10 mg/kg, i.p.) significantly enhanced the anticonvulsant action of carbamazepine, phenytoin, phenobarbital and valproate in the MES test in mice. WIN (5 mg/kg) potentiated the anticonvulsant action of carbamazepine and valproate, but not that of phenytoin or phenobarbital in the MES test in mice. However, WIN administered alone and in combination with carbamazepine, phenytoin, phenobarbital and valproate significantly reduced muscular strength in mice in the grip-strength test. In the passive avoidance task, WIN in combination with phenobarbital, phenytoin and valproate significantly impaired long-term memory in mice. In the chimney test, only the combinations of WIN with phenobarbital and valproate significantly impaired motor coordination in mice. In conclusion, WIN enhanced the anticonvulsant action of carbamazepine, phenytoin, phenobarbital and valproate in the MES test. However, the utmost caution is advised when combining WIN with classical antiepileptic drugs due to impairment of motor coordination and long-term memory and/or reduction of skeletal muscular strength that might appear during combined treatment.

[Epilepsy in elderly]

Seventy-two elderly patients with a possible diagnosis of epilepsy were studied. A study included the evaluation of anamnesis, clinical and neurological examination, EEG and/or video-EEG-monitoring, MRI of the brain. The follow-up period was 1-5 years (on average 3 years). Epilepsy was confirmed in 58 cases. Symptomatic partial epilepsy was diagnosed in 43,1% patients, cryptogenic - in 55,2%. Cerebrovascular accidents were the most frequent cause of symptomatic epilepsy. The distinct feature of the cohort studied was the non-compliance recorded in a half of all patients. In the end of the study, 46,6% patients received carbamazepine, 34,5% - valproate, 24,1% - phenobarbital, 13,8% - topiramate, 3,4% - phenytoin, 1,7% - lamotrigine and 12,1% of patients did not use antiepileptic drugs. Clinical features, efficacy of diagnosis and treatment as well as reasons of non-compliance in elderly epileptic patients were described and analyzed.

A case of drug-induced hypersensitivity syndrome-like symptoms following HHV-6 encephalopathy

BACKGROUND

Drug-induced hypersensitivity syndrome (DIHS) is a rare but severe disorder due to a systemic hypersensitivity reaction. We report on a case with DIHS-like symptoms following human herpes virus 6 (HHV-6) infection complicated with encephalopathy.

CASE SUMMARY

An 11-month-old girl suffered from a human herpes virus 6 (HHV-6) infection (exanthema subitum) complicated with encephalopathy. We treated the patient with continuous infusion of thiopental, assisted mechanical ventilation, methylprednisolone pulse therapy, and gamma-globulin infusion therapy starting on the fifth day of the illness and started phenobarbital administration on the eleventh day. The patient developed a fever, systemic erythematous exanthema, lymphadenopathy, and eosinophilia two weeks after the start of phenobarbital administration. Steroid therapy, methylprednisolone (4 mg/kg/day) followed by oral prednisolone (1 mg/kg/day), was started on the 28th day and was tapered off on the 72nd day after admission. Serum anti-HHV-6 IgG antibody elevation and the presence of HHV-6 DNA in the peripheral blood detected by polymerase chain reaction (PCR) analysis suggested reactivation of HHV-6 after the primary infection of HHV-6. Lymphocyte transformation test for phenobarbital was positive three weeks after the DIHS crisis.

DISCUSSION

HHV-6 reactivation is a unique feature in DIHS. In general one develops DIHS accompanied by reactivation of HHV-6 which has been residing in the body since the initial infection (exanthema subitum) in early childhood. This is the first report of a patient with DIHS-like symptoms which developed immediately following the primary infection of HHV-6.

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

BACKGROUND

Phenobarbital is one of the oldest, cheapest and most easily available cerebro-protective drugs for the hypoxic brain. It has multiple actions that could be of benefit to the asphyxiated brain. However, its potential has not been fully explored.

OBJECTIVE

To study the effect of phenobarbital given within six hours of life to term and near-term asphyxiated neonates, on mortality, neurological abnormality at discharge and seizures.

METHODS

This was a randomized controlled trial set in a tertiary care referral perinatal centre. Asphyxiated neonates (gestational age >or= 34 weeks) manifesting with hypoxic ischemic encephalopathy (HIE) in the first six hours of life were randomized to receive either injection of phenobarbital 20 mg/kg IV or to the control group. The primary outcome was death or abnormal neurological examination at discharge while seizures, need for ventilation and multi-organ dysfunction were secondary outcomes.

RESULTS

Twenty-five babies received phenobarbital and 20 were in the control group. The mortality (20% vs. 15%) and abnormal neurological outcome at discharge (30% vs. 53%, p = 0.15) were statistically not different between the two groups. In the phenobarbital group, 8% of neonates developed seizures while 40% of babies in the control group developed seizures (p = 0.01, relative risk (RR) = 0.20 (0.05-0.84)). Phenobarbital was well tolerated and did not increase the need for respiratory support.

CONCLUSIONS

Phenobarbital in the dose of 20 mg/kg IV given within six hours of life to term and near-term neonates with HIE, significantly decreased the incidence of neonatal seizures and was well tolerated. However, it did not alter the mortality and neurologic outcome at discharge.