SEW2871 reduces seizures via the sphingosine 1-phosphate receptor-1 pathway in the pentylenetetrazol and phenobarbitone kindling model of drug-refractory epilepsy.

Epilepsy is a prevalent neurological disorder characterized by neuronal hypersynchronous discharge in the brain, leading to central nervous system (CNS) dysfunction. Despite the availability of anti-epileptic drugs (AEDs), resistance to AEDs is the greatest challenge in treating epilepsy. The role of sphingosine-1-phosphate-receptor 1 (S1PR1) in drug-resistant epilepsy is unexplored. This study investigated the effects of SEW2871, a potent S1PR1 agonist, on a phenobarbitone (PHB)-resistant pentylenetetrazol (PTZ)-kindled Wistar rat model. We measured the messenger ribonucleic acid (mRNA) expression of multi-drug resistance 1 (MDR1) and multi-drug resistance protein 5 (MRP5) as indicators for drug resistance. Rats received PHB + PTZ for 62 days to develop a drug-resistant epilepsy model. From day 48, SEW2871 (0.25, 0.5, 0.75 mg/kg, intraperitoneally [i.p.]) was administered for 14 days. Seizure scoring, behaviour, oxidative markers like reduced glutathione, catalase, superoxide dismutase, inflammatory markers like interleukin 1 beta tumour necrosis factor alpha, interferon gamma and mRNA expression (MDR1 and MRP5) were assessed, and histopathological assessments were conducted. SEW2871 demonstrated dose-dependent improvements in seizure scoring and neurobehavioral parameters with a reduction in oxidative and inflammation-induced neuronal damage. The S1PR1 agonist also downregulated MDR1 and MRP5 gene expression and significantly decreased the number of dark-stained pyknotic nuclei and increased cell density with neuronal rearrangement in the rat brain hippocampus. These findings suggest that SEW2871 might ameliorate epileptic symptoms by modulating drug resistance through downregulation of MDR1 and MRP5 gene expression.

Unmasking hidden risks: The surprising link between PDE5 inhibitors and seizure susceptibility.

BACKGROUND: Phosphodiesterase 5 inhibitors (PDE5i) are the first line treatment for erectile dysfunction; however, several articles and case reports have shown central nervous system effects, that can cause seizures in susceptible patients. This study aims to describe the changes caused by the use of Sildenafil and Tadalafil through the analysis of abnormalities expressed in the electrocorticogram (ECoG) of rats and evaluate the seizure threshold response and treatment of seizures with anticonvulsants. MATERIALS AND METHODS: The study used 108 rats (Wistar). Before surgery for electrode placement in dura mater, the animals were randomly separated into 3 experiments for electrocorticogram analysis. Experiment 1: ECoG response to using PD5i (Sildenafil 20mg/kg and Tadalafil 2.6mg/kg p.o.). Experiment 2: ECoG response to the use of PD5i in association with Pentylenetetrazole (PTZ-30 mg/kg i.p.), a convulsive model. Experiment 3: ECoG response to anticonvulsant treatment (Phenytoin, Phenobarbital and Diazepam) of seizures induced by association IPDE5 + PTZ. All recordings were made thirty minutes after administration of the medication and analyzed for ten minutes, only once. We considered statistical significance level of *p<0.05, **p<0.01 and ***p < 0.001. RESULTS: After administration of Sildenafil and Tadalafil, there were increases in the power of recordings in the frequency bands in oscillations in alpha (p = 0.0920) and beta (p = 0.602) when compared to the control group (p<0.001). After the use of Sildenafil and Tadalafil associated with PTZ, greater potency was observed in the recordings during seizures (p<0.001), however, the Sildenafil group showed greater potency when compared to Tadalafil (p<0.05). Phenobarbital and Diazepam showed a better response in controlling discharges triggered by the association between proconvulsant drugs. CONCLUSIONS: PDE5i altered the ECoG recordings in the rats' motor cortexes, demonstrating cerebral asynchrony and potentiating the action of PTZ. These findings demonstrate that PDE5i can lower the seizure threshold.

A retrospective evaluation of phenobarbital-induced hematologic changes in 69 cats.

BACKGROUND: Phenobarbital (PB) is used as a first-line treatment for recurrent epileptic seizures in cats. While hematologic abnormalities are well-known side effects of antiepileptic therapy with PB in humans and dogs, little is known about such alterations in cats. OBJECTIVES: The aim of this retrospective study was to investigate the prevalence and clinical relevance of cytopenia during PB treatment in cats. METHODS: In this single-center, retrospective clinical study, 69 cats-with suspected idiopathic epilepsy admitted to the Small Animal Clinic of the University of Veterinary Medicine in Vienna (VMU)-were included. A complete blood count for each patient was performed, and changes in hematocrit, leukocytes, neutrophils, and thrombocytes were documented and graded. RESULTS: Fifty-three out of 69 cats (76.8%) showed cytopenias with a reduction of at least one cell fraction during PB treatment. The most frequent change was neutropenia (60%), followed by leukopenia (49.3%), thrombocytopenia (24.1%), and anemia (20.3%). Most of the changes were mild or moderate; only one patient (1.5%) showed severe leukopenia and neutropenia, and one was a life-threatening neutropenia (1.5%) with a serum PB concentration within or even below the therapeutic range. These patients did not present with clinical symptoms other than those related to epileptic episodes. Cats who received combination therapy showed lower hematocrits than those who received monotherapy. A tendency for leukocytes and neutrophils to decrease during PB treatment was also seen. CONCLUSIONS: Blood cytopenias may frequently occur in cats on chronic PB therapy, even when serum drug levels are within the therapeutic range. However, clinical signs are typically mild to moderate and rarely severe.

Presumptive phenobarbital-induced systemic lupus erythematosus in a domestic dog.

CASE DESCRIPTION: We describe a case of presumptive acquired systemic lupus erythematosus secondary to phenobarbital administration in a dog, which resolved with withdrawal of the drug. CLINICAL FINDINGS: A 3.5 year-old poodle presented to a veterinary teaching hospital for Tier 1 idiopathic epilepsy and was treated with phenobarbital. The dog experienced fever, multiple cytopenias, and proteinuria in conjunction with a positive antinuclear antibody (ANA) titer. DIAGNOSTICS: Serial CBCs, urine protein : creatinine ratios, and sternal bone marrow aspirates were performed to evaluate improvement. TREATMENT AND OUTCOME: Phenobarbital was withdrawn and levetiracetam initiated. All abnormalities resolved with supportive care, without initiation of immunosuppressive drugs. All cytopenias and proteinuria resolved and ANA test results became negative within 3 months. The patient recovered and did well clinically. CLINICAL RELEVANCE: Systemic lupus erythematosus is a disease of multiple autoimmune syndromes occurring concurrently or sequentially in conjunction with the presence of circulating ANA. It has been well described in dogs as an idiopathic condition, but in human medicine may occur secondary to drug reactions (drug-associated lupus) including as a reaction to phenobarbital. The findings in our case are consistent with the criteria for drug-induced lupus in humans and we suggest it as the first report of phenobarbital-induced lupus in a dog.

Phenobarbital versus benzodiazepines in alcohol withdrawal syndrome.

AIM: Phenobarbital, a long-acting barbiturate, presents an alternative to conventional benzodiazepine treatment for alcohol withdrawal syndrome (AWS). Currently, existing research offers only modest guidance on the safety and effectiveness of phenobarbital in managing AWS in hospital settings. The study objective was to assess if a phenobarbital protocol for the treatment of AWS reduces respiratory complications when compared to a more traditionally used benzodiazepine protocol. METHODS: A retrospective cohort study analyzing adults who received either phenobarbital or benzodiazepine-based treatment for AWS over a 4-year period, 2015-2019, in a community teaching hospital in a large academic medical system. RESULTS: A total of 147 patient encounters were included (76 phenobarbital and 71 benzodiazepine). Phenobarbital was associated with a significantly decreased risk of respiratory complications, defined by the occurrence of intubation (15/76 phenobarbital [20%] vs. 36/71 benzodiazepine [51%]) and decreased incidence of the requirement of six or greater liters of oxygen when compared with benzodiazepines (10/76 [13%] vs. 28/71 [39%]). There was a significantly higher incidence of pneumonia in benzodiazepine patients (15/76 [20%] vs. 33/71 [47%]). Mode Richmond Agitation Sedation Scale (RASS) scores were more frequently at goal (0 to -1) between 9 and 48 h after the loading dose of study medication for phenobarbital patients. Median hospital and ICU length of stay were significantly shorter for phenobarbital patients when compared with benzodiazepine patients (5 vs. 10 days and 2 vs. 4 days, respectively). CONCLUSION: Parenteral phenobarbital loading doses with an oral phenobarbital tapered protocol for AWS resulted in decreased risk of respiratory complications when compared to standard treatment with benzodiazepines.

Phenobarbital for the Management of Alcohol Withdrawal Syndrome in Critically Ill, Surgical-Trauma Patients.

INTRODUCTION: While benzodiazepines (BZD) are the standard of care therapy for the management alcohol withdrawal syndrome (AWS), phenobarbital (PHB) is often used as an alternative agent. The objective of this study is to assess the use of PHB therapy for the management of AWS in trauma-surgical intensive care unit (TSCU) patients. MATERIALS AND METHODS: This is an institutional review board-approved single-center, retrospective study conducted at a large academic medical center. Patients aged ≥ 18 y admitted to the TSCU receiving PHB therapy for primary management of AWS were included. The primary outcome evaluated was the incidence of AWS-related complications (AWSRC) defined as severe agitation, delirium tremens, or seizures following initiation of PHB. Secondary outcomes included the incidence of oversedation and duration of mechanical ventilation. RESULTS: Sixty patients were included in this study. AWSRC following initiation of PHB occurred in 65% of patients. Median time to initiation of PHB (42 versus 18 h, P = 0.001) and rates of oversedation (79.5% versus 28.6%, P < 0.001) were significantly greater among patients who experienced AWSRC compared to those who did not. Univariate analysis revealed use of BZD therapy for ≥ 24 h prior to PHB initiation, time from hospital admission to PHB initiation ≥ 24 h, presence of AWS symptoms at baseline, and baseline MINDS score > 6 were risk factors for AWSRC. CONCLUSIONS: Delays in initiation of PHB appear to be associated with an increased risk for developing AWSRC. Further research is needed to identify an optimal dosing strategy for TSCU patients at high risk for severe AWS.

The Use of a Single Dose of Phenobarbital for Inpatient Management of Benzodiazepine Withdrawal: A Case Report.

INTRODUCTION: The current standard of care for physiological dependence to benzodiazepines requires prolonged outpatient tapers, which present challenges for patients and providers. Novel protocols for accelerated benzodiazepine tapers are needed. We describe a case of successful management of benzodiazepine withdrawal in the inpatient setting using a single, loading dose of phenobarbital with adjunctive valproate therapy. CASE REPORT: A 61-year-old woman with benzodiazepine use disorder using 3 to 4 mg of alprazolam daily presented to an inpatient medically supervised withdrawal unit requesting discontinuation of all benzodiazepines and other recreational substances by the time of discharge. Benzodiazepine withdrawal was treated with a single, loading dose of intravenous phenobarbital in line with an approved protocol for the treatment of alcohol withdrawal, as well as adjunctive valproate therapy. The patient experienced resolution of withdrawal symptoms, had no complications, and ongoing abstinence at 60 days of follow-up. DISCUSSION: A single loading dose of phenobarbital in the inpatient setting is a viable alternative to prolonged outpatient tapers for the management of benzodiazepine withdrawal. Although this strategy requires further optimization, the prospect of a single-dose treatment for benzodiazepine withdrawal creates exciting opportunities for alternative management options and settings. CONCLUSIONS: This case describes the successful management of benzodiazepine withdrawal syndrome using a single loading dose of intravenous phenobarbital derived from an approved protocol for alcohol withdrawal syndrome.

Effects of antiepileptic drugs polytherapy on pregnancy outcomes in women with epilepsy: An observation study in northwest China.

OBJECTIVE: The management of pregnant women with epilepsy (WWE) treated with antiepileptic drugs (AEDs) polytherapy poses a great challenge. The purpose of this study was to evaluate the major congenital malformations (MCMs) associated with AED polytherapy, to assess the impacts of polytherapy regimens on seizure control and breastfeeding, and to determine the potential predictors for pregnancy outcomes. METHODS: This study was based on prospectively acquired data from a registry enrolling WWE in early pregnancy from Feb 2010 to July 2019, in which 123 pregnancies in 110 WWE were exposed to 27 different AED combinations. RESULTS: There were 123 pregnancies in 110 WWE analyzed in our study. The live birth rate was 86.2 % and the risk of MCMs was 10.4 %. Multivariate analysis indicated that prenatal exposure to phenobarbital (odds ratio [OR], 17.424; 95 %CI, 1.510-201.067; P = 0.022) and topiramate (OR, 9.469; 95 %CI, 1.149-62.402; P = 0.036) was associated with increased risk of MCMs. Valproate (OR, 4.441; 95 %CI, 1.165-16.934; P = 0.029), phenobarbital (OR, 13.636; 95 %CI, 2.146-86.660; P = 0.006) and topiramate (OR, 7.527; 95 %CI, 1.764-32.118; P = 0.006) were significantly correlated with adverse pregnancy outcomes. Among 67 pregnancies in four combinations over 10 patients, 15 (22.4 %) remained seizure free through pregnancy, seizure frequency increased in 17 (25.4 %), decreased in 24 (35.8 %) women, in 26 (38.8 %) remained unchanged. Only 23.6 % of mothers undertook exclusive breastfeeding. Planned pregnancy was the only independent factor significantly associated with decreased risk of adverse pregnancy outcomes (OR, 0.139; 95 % CI, 0.051-0.382; P < 0.001). Notably, no adverse pregnancy outcome was recorded in pregnancies exposed to the combination of lamotrigine plus levetiracetam. CONCLUSION: Prenatal exposure to the combinations containing valproate, phenobarbital, or topiramate was associated with increased risk of adverse pregnant outcomes. AED-related teratogenicity may be reduced by planned pregnancy in WWE exposed to polytherapy. Our findings also suggest the combination of lamotrigine and levetiracetam seems to be most desirable to balance seizure control and fetal safety.

Front-Loaded Versus Low-Intermittent Phenobarbital Dosing for Benzodiazepine-Resistant Severe Alcohol Withdrawal Syndrome.

INTRODUCTION: Phenobarbital is frequently used to manage severe alcohol withdrawal. The purpose of this study was to compare the incidence of mechanical ventilation in patients with benzodiazepine-resistant alcohol withdrawal between front-loaded and low-intermittent phenobarbital dosing strategies. METHODS: In this retrospective before-after study, we analyzed patients that received phenobarbital for severe alcohol withdrawal syndrome in a tertiary medical ICU. Patients received low-intermittent phenobarbital doses (260 mg intravenous push × 1 followed by 130 mg intravenous push every 15 min as needed) from January  2013 to July 2015, and front-loaded phenobarbital doses (10 mg/kg intravenous infusion over 30 min) from July 2015 to January 2017. RESULTS: In total, 87 patients met inclusion criteria for this study: 41 received low-intermittent phenobarbital and 46 received front-loaded phenobarbital). The incidence of mechanical ventilation was 13 (28%) in the front-loaded dosing group vs. 26 (63%) in the low-intermittent dosing group (odds ratio 4.4 [95% CI 1.8-10.9]). The cumulative dose of phenobarbital administered and serum phenobarbital levels were similar between both groups, although the front-loaded group had significantly lower benzodiazepine requirements than the low-intermittent group (median 86 mg [IQR 24-197] vs. 228 mg [115-298], P < 0.01) and reduced need for any continuous sedative infusion (OR 7.7 [95% CI 1.6-27], P < 0.01). There was no difference in respiratory failure or hypotension. CONCLUSIONS: Front-loaded phenobarbital dosing, when compared to low-intermittent phenobarbital dosing, for benzodiazepine-resistant alcohol withdrawal was associated with significantly lower mechanical ventilation incidence and continuous sedative use.

Side effects of long-term oral anti-seizure drugs on thyroid hormones in patients with epilepsy: a systematic review and network meta-analysis.

INTRODUCTION: Anti-seizure drugs have long been known to affect thyroid hormone levels in epilepsy patients. The current study is a network meta-analysis designed to produce a systematic review and comprehensive evaluation of thyroid hormone changes to inform future research and clinical treatment. METHOD: A systematic search of databases, PubMed, EMBASE, Web of Science, and the Cochrane Library, was conducted and all observational studies reporting thyroid hormone levels in epilepsy patients receiving monotherapy and controls were included. Stata MP.14 was used for analysis. RESULTS: A total of 35 studies, including 4135 participants and 8 anti-seizure drugs, were analyzed. TSH levels were elevated following use of topiramate [mean = 1.86; 95%CI: 0.83 to 2.90], levetiracetam [mean = 1.08; 95%CI: 0.07 to 2.09], and valproic acid [mean = 1.54; 95%CI: 0.58 to 2.50]. FT4 levels may be lowered by oxcarbazepine [mean = - 6.13; 95%CI: - 8.25 to - 4.02] and T4 was lowered by carbamazepine [mean = - 1.55; 95%CI: - 2.05 to - 1.05] and phenytoin [mean = - 1.33; 95%CI: - 1.80 to - 0.85]. No significant changes were reported for FT3, although use of phenobarbital resulted in a non-significant decrease [mean = - 0.31; 95%CI: - 0.99 to 0.37]. T3 levels were lowered by carbamazepine [mean = - 0.52; 95%CI: - 0.81 to - 0.24]. Lamotrigine had no significant effect on thyroid hormone levels. CONCLUSION: Carbamazepine and phenytoin were the drugs most strongly associated with decreases in T4 and T3 levels while topiramate had the greatest elevating effect on TSH. Oxcarbazepine may lead to decreased serum FT4 and FT3, an effect relevant to central hypothyroidism. Phenobarbital appeared to significantly lower FT3. Use of levetiracetam and valproic acid may result in subclinical hypothyroidism. The anti-seizure drug with the least disruptive effect on thyroid hormone levels was found to be lamotrigine.

Nrf2-Dependent Protective Effect of Paeoniflorin on α-Naphthalene Isothiocyanate-Induced Hepatic Injury.

The pathological mechanism of cholestatic hepatic injury is associated with oxidative stress, hepatocyte inflammation, and dysregulation of hepatocyte transporters. Paeonia lactiflora Pall. and its compound can improve hepatic microcirculation, dilate bile duct, and promote bile flow, which is advantageous to ameliorate liver damage. Paeoniflorin (PEA), as the main efficacy component of Paeonia lactiflora Pall., has multiple pharmacological effects. PEA improves liver injury, but it remains obscure whether the protective action on [Formula: see text]-naphthalene isothiocyanate (ANIT)-induced cholestatic liver injury is dependent on the NF-E2 p45-related Factor 2 (Nrf2) signaling pathway. In this study, C57BL/6 mice were administrated with 80 mg⋅kg[Formula: see text]⋅d[Formula: see text] ANIT followed by PEA (75, 150, and 300 mg⋅kg[Formula: see text]⋅d[Formula: see text]) orally for 10 days, respectively. Tissue histology and liver function were detected, including serum enzymes, gallbladder (GB) weight, phenobarbital-induced sleeping time (PEN-induced ST), hepatic uridine di-phosphoglucuronosyltransferase (UDPG-T), malondialdehyde (MDA), and glutathione (GSH). The expressions of protein Nrf2, sodium taurocholate cotransporting polypeptide (Ntcp), and NADPH oxidase 4 (Nox4) were evaluated. Nrf2 plasmid or siRNA-Nrf2 transfection on LO2 cells and Nrf2-/- mice were used to explore the liver protective mechanism of PEA. Compared to ANIT-treated mice, PEA decreased serum levels of alanine aminotransferase (ALT), aspartate aminotransferase (AST), alkaline phosphatase (ALP), total bilirubin (TBIL), direct bilirubin (DBIL), total bile acid (TBA), and phenobarbital-induced sleeping time. The bile secretion, hepatic UDPG-T, MDA, GSH, and liver histology were improved. The expressions of protein Nrf2 and Ntcp in liver tissues increased, but Nox4 decreased. After Nrf2 plasmid or small interfering RNA (siRNA)-Nrf2 transfection, the protective effects of PEA on LO2 cells were, respectively, strengthened or weakened. Moreover, PEA had no significant effects on ANIT-treated Nrf2-/- mice. Our results suggest that Nrf2 is essential for PEA protective effects on ANIT-induced liver injury.

Neuropsychological effects in children exposed to anticonvulsant monotherapy during gestation: Phenobarbital, carbamazepine, and phenytoin.

OBJECTIVE: Usage during pregnancy of the antiseizure medication (ASM), phenobarbital (PB), carbamazepine (CBZ), and phenytoin (PHT), has been associated with adverse pregnancy outcomes. While morphological effects on offspring are well-documented, inconsistent findings have been reported on neuropsychological development, possibly due to differences in attention to maternal demographics, and other design characteristics. Herein, we report the results of a carefully designed protocol used to examine the effects of gestational monotherapy with PB, CBZ, or PHT upon children's general mental abilities, when compared to age- and gender- matched children born to unexposed women of similar age, education, and socioeconomic status. METHODS: For each ASM, we selected qualifying cases from children born to PB, CBZ, or PHT monotherapy-exposed and unexposed women. Following the application of inclusion, exclusion, and matching criteria, our sample included 34 PB-exposed, 40 PHT-exposed, and 41 CBZ-exposed children along with matched unexposed children for each drug group. Criteria were applied through examination of maternal medical and educational histories, parental socioeconomic characteristics, and child's age and gender. Each child's physical and neuropsychological characteristics were examined, using standardized protocols. We report on the cognitive performance of the children as assessed by the Wechsler Intelligence Scale for Children - III (WISC-III), the leading measure of mental ability in the U.S. RESULTS: An overall mixed model ANOVA of the adjusted performance of the children across all groups controlling for maternal IQ revealed significant effects on verbal IQ, but not full-scale IQ or performance IQ. In the individual drug and unexposed group comparisons, only reduced verbal and full-scale IQ scores in PB-exposed versus matched unexposed children were found. Comparisons between drug groups revealed a significant reduction in verbal IQ and full-scale IQ in PB-exposed versus PHT-exposed children, but not in other drug-drug comparisons. SIGNIFICANCE: These results demonstrate effects on children's mental ability due to prenatal PB exposure, such that analyses adjusted for maternal IQ scores, revealed reduced verbal mental abilities and reduced full-scale IQ scores when scores in exposed children were compared to scores from children of the same age and sex born to demographically similar, healthy unexposed women. When comparisons were made between drug groups, children exposed prenatally to PB performed significantly worse than prenatally PHT-exposed children, but CBZ-exposed children's scores were not significantly different from those of PB or PHT-exposed groups. In light of shared effects on structural teratogenicity, these findings suggest that use of PB monotherapy for the management of seizures during pregnancy may be associated with increased risk in comparison to PHT when neurobehavioral functioning is considered, and that only PB-exposed children have reduced performance compared to matched controls. Attention to these effects is critical in the developing world where use of these older medications remains predominant, and prudent choices can be made to reduce impact on cognitive development.

Is Maternal Methadone Dose Associated with the Severity of Neonatal Abstinence Syndrome?

OBJECTIVE: The aim of the study is to assess the correlation between maternal methadone dose and severity of neonatal abstinence syndrome (NAS) in infants that required pharmacological treatment for NAS. STUDY DESIGN: This is a retrospective analysis of 574 infants ≥35 weeks' gestation exposed to methadone in utero, born between August 2006 and May 2018, and who required pharmacological therapy for NAS. Indicators of NAS severity (duration of morphine treatment, maximum morphine dose, use of phenobarbital, and length of hospitalization) were compared between infants exposed to high (≥200 mg), intermediate (100-199 mg), and low doses (<100 mg) of methadone. Logistic and linear regression models were used to adjust for the covariates. RESULTS: Median (interquartile range) duration of medical treatment with morphine was higher in infants exposed to higher doses of methadone (low dose 23 [14-37] days, intermediate dose 31 [18-45] days, and high dose 35 [20-48] days, p < 0.001). Higher methadone doses were also predictive of longer duration of hospitalization, higher maximum morphine dose, and increased likelihood of treatment with phenobarbital. The association between maternal methadone dose and the severity of NAS persisted in multivariable regression models. CONCLUSION: Infants exposed to higher methadone doses displayed more severe NAS, as indicated by longer durations of treatment, higher maximum morphine dose, longer duration of hospitalization, and increased likelihood of phenobarbital use. KEY POINTS: · Methadone maintenance therapy is used during pregnancy to control maternal withdrawal symptoms.. · Relationship between maternal methadone dose and severity of NAS is not adequately investigated.. · Increased doses of methadone during pregnancy correlate with increased severity of NAS..

Evaluation of the effect of phenobarbital administration on the biochemistry profile, with a focus on serum liver values, in epileptic cats.

OBJECTIVES: Phenobarbital (PB) is the most common antiseizure drug (ASD) used for the management of feline epilepsy. In dogs, PB is known to cause serum liver enzyme induction and hepatotoxicity, especially after administration long term or in high concentrations. In cats, insufficient evidence is available to draw similar conclusions. The aim of this study was to evaluate the effect of PB administration on the serum biochemistry profile of epileptic cats. As an additional objective, other adverse effects arising, related to PB treatment, were recorded. METHODS: Medical records of four veterinary centres were retrospectively reviewed for epileptic cats receiving PB treatment. Cats were included if they had a diagnosis of idiopathic epilepsy or structural epilepsy; a normal baseline serum biochemistry profile; at least one follow-up serum biochemistry profile; no concurrent disease or had not received medication that could possibly influence liver function or lead to serum liver enzyme induction. Alkaline phosphatase, alanine aminotransferase (ALT), aspartate transaminase and gamma-glutamyl transferase activities, and total bilirubin, bile acids, glucose, albumin, total protein, urea and creatinine concentrations before and during PB administration were recorded. PB serum concentration was also recorded, when available. RESULTS: Thirty-three cats (24 males, nine females) with a median age of 3 years (range 2 months to 12 years) met the inclusion criteria. Idiopathic or structural epilepsy was diagnosed in 25 (76%) and eight (24%) cats, respectively. The follow-up period ranged from 9 to 62 months. This study found an increase in ALT in three cats, possibly related to a PB serum concentration >30 µg/ml. No statistically significant increase in serum liver enzymes or other evaluated biochemistry parameters was found by comparing pre- and post-treatment parameters. CONCLUSIONS AND RELEVANCE: PB administration did not result in hepatic enzyme induction or other biochemical abnormalities in cats. This strengthens the safety profile of PB as an ASD in cats.

Pancytopenia secondary to suspected idiosyncratic phenobarbital reaction in a dog.

A 4-year-old neutered male St. Bernard-mastiff crossbred dog showed clinical signs of lethargy and anorexia after being administered phenobarbital for the treatment of idiosyncratic seizures. A complete blood (cell) count revealed pancytopenia. Auto-agglutination and Coombs tests were negative suggesting that an immunemediated cause was unlikely; therefore, an idiosyncratic reaction to phenobarbital was suspected. Supportive care and control of seizures with zonisamide was initiated and clinical signs improved. Blood values were monitored closely and returned to normal after 3 wk.

Pancytopénie secondaire à une suspicion de réaction idiosyncratique au phénobarbital chez un chien. Un chien mâle castré de 4 ans croisé St-Bernard-mastiff a montré des signes cliniques de léthargie et d'anorexie après avoir reçu du phénobarbital pour le traitement de crises idiosyncratiques. Une numération cellulaire sanguine complète a révélé une pancytopénie. Les tests d'auto-agglutination et de Coombs étaient négatifs, suggérant qu'une cause à médiation immunitaire était peu probable; par conséquent, une réaction idiosyncratique au phénobarbital a été suspectée. Des soins de soutien et la maitrise des crises avec le zonisamide ont été initiés et les signes cliniques se sont améliorés. Les valeurs sanguines ont été étroitement surveillées et sont revenues à la normale après 3 semaines.(Traduit par Dr Serge Messier).

Development of an antiepileptogenesis drug screening platform: Effects of everolimus and phenobarbital.

OBJECTIVE: The kainic acid (KA)-induced status epilepticus (SE) model in rats is a well-defined model of epileptogenesis. This model closely recapitulates many of the clinical and pathological characteristics of human temporal lobe epilepsy (TLE) that arise following SE or another neurological insult. Spontaneous recurrent seizures (SRS) in TLE can present after a latent period following a neurological insult (traumatic brain injury, SE event, viral infection, etc.). Moreover, this model is suitable for preclinical studies to evaluate the long-term process of epileptogenesis and screen putative disease-modifying/antiepileptogenic agents. The burden of human TLE is highly variable, similar to the post-KA SE rat model. In this regard, this model may have broad translational relevance. This report thus details the pharmacological characterization and methodological refinement of a moderate-throughput drug screening program using the post-KA-induced SE model of epileptogenesis in male Sprague Dawley rats to identify potential agents that may prevent or modify the burden of SRS. Specifically, we sought to demonstrate whether our protocol could prevent the development of SRS or lead to a reduced frequency/severity of SRS. METHODS: Rats were administered either everolimus (2-3 mg/kg po) beginning 1, 2, or 24 h after SE onset, or phenobarbital (60 mg/kg ip) beginning 1 h after SE onset. All treatments were administered once/day for 5-7 days. Rats in all studies (n = 12/treatment dose/study) were then monitored intermittently by video-electroencephalography (2 weeks on, 2 weeks off, 2 weeks on epochs) to determine latency to onset of SRS and disease burden. RESULTS: Although no adverse side effects were observed in our studies, no treatment significantly modified disease or prevented the presentation of SRS by 6 weeks after SE onset. SIGNIFICANCE: Neither phenobarbital nor everolimus administered at several time points after SE onset prevented the development of SRS. Nonetheless, we demonstrate a practical and moderate-throughput screen for potential antiepileptogenic agents in a rat model of TLE.

Bone marrow, blood, and clinical findings in dogs treated with phenobarbital.

BACKGROUND: Cytopenias have been reported in dogs treated with phenobarbital, but detailed descriptions of bone marrow findings and response to treatment are lacking. OBJECTIVES: We aimed to characterize the hematologic findings and clinical outcomes of dogs that had been receiving phenobarbital at the time of marrow evaluation. METHODS: Archived bone marrow slides and clinicopathologic data were reviewed in dogs undergoing marrow evaluation for any hematologic problems that developed while receiving phenobarbital (2008-2020). Dogs were excluded if marrow samples lacked diagnostic value, phenobarbital was withdrawn >1 day before marrow collection, a same-day complete blood count (CBC) was lacking, or dogs had concurrent illness or therapy known to cause cytopenias. RESULTS: Thirteen dogs met inclusion criteria: eight pancytopenic, three anemic/thrombocytopenic, one neutropenic/thrombocytopenic, and one nearly neutropenic. Neutropenia was marked (<700/µL) in eight dogs; all neutrophil concentrations were low or low-normal. Of the 11 anemic dogs (Hct = 12%-42%, median = 29%), three had mild reticulocytosis (eight were tested). One dog had erythroid dysplasia in blood and marrow. All nine neutropenic dogs had evidence of ineffective neutropoiesis: neutrophilic hyperplasia with left shift (9) ± neutrophagocytosis (5). Eight of the 11 anemic dogs had evidence of ineffective erythropoiesis: erythroid hyperplasia (7), left shift (3), and/or rubriphagocytosis (6). No thrombocytopenic dog had megakaryocytic hypoplasia; seven dogs had megakaryocytic hyperplasia. One anemic/thrombocytopenic dog had marked collagen myelofibrosis. The noncytopenic dog had equivocal myeloid hypoplasia with neutrophagocytosis. Median maximal responses and resolution times for neutropenia (n = 6) were 14 days. CONCLUSIONS: Phenobarbital-induced cytopenias should be considered in dogs with multilineage ineffective hematopoiesis, particularly when neutropenia and myeloid hyperplasia are present. However, findings in dogs with immune-mediated neutropenia or precursor-targeted immune-mediated anemia might be indistinguishable.