-
Veterinary Sciences Jun 2024Seizures are a common presentation seen in small animal practices. Seizures require prompt management including initial interventions for triage, stabilization, and... (Review)
Review
Seizures are a common presentation seen in small animal practices. Seizures require prompt management including initial interventions for triage, stabilization, and treatment with first-line anticonvulsant (AC) drugs like benzodiazepines. Concurrently, ruling out metabolic or extracranial causes with point-of-care diagnostics can help guide further diagnostics and treatments. Analysis of the history and a physical exam are also necessary to rule out common "look-alikes" that require specific diagnostic workup and treatments. Typically, causes of seizures can be grouped into intracranial and extracranial causes, with the latter being easier to diagnose with commonly available tests. This review presents a systematic approach to the diagnosis and treatment of single seizures, cluster seizures, and status epilepticus in dogs and cats.
PubMed: 38922024
DOI: 10.3390/vetsci11060277 -
Drug Metabolism and Disposition: the... Jun 2024Asphyxiated neonates often undergo therapeutic hypothermia (TH) to reduce morbidity and mortality. Since both perinatal asphyxia (PA) and TH influence physiology,...
Asphyxiated neonates often undergo therapeutic hypothermia (TH) to reduce morbidity and mortality. Since both perinatal asphyxia (PA) and TH influence physiology, altered pharmacokinetics (PK) and pharmacodynamics (PD) are expected. Given that TH is the standard of care for PA with moderate to severe hypoxic-ischemic encephalopathy (HIE), disentangling the effect of PA versus TH on PK/PD is not possible in clinical settings. However, animal models can provide insights into this matter. The (neonatal) Göttingen Minipig, the recommended strain for nonclinical drug development, was selected as translational model. Four drugs - midazolam (MDZ), fentanyl (FNT), phenobarbital (PHB), and topiramate (TPM), were intravenously administered under four conditions: control (C), therapeutic hypothermia (TH), hypoxia (H), hypoxia + TH (H+TH). Each group included six healthy male neonatal Göttingen Minipigs anesthetized for 24 hours. Blood samples were drawn at 0 (pre-dose), and 0.5, 2, 2.5, 3, 4, 4.5, 6, 8, 12, 24 hours post-drug administration. Drug plasma concentrations were determined using validated bioanalytical assays. The PK parameters were estimated through compartmental and non-compartmental PK analysis (NCA). The study showed a statistically significant decrease in FNT clearance (CL, 66% decrease) with approximately 3-fold longer half-life (t) in the TH group. The H+TH group showed a 17% reduction in FNT CL with a 62% longer t compared to the C group, however non-statistically significant. Trends towards lower CL and longer t were observed in the TH and H+TH groups for MDZ and PHB. Additionally, TPM demonstrated a 28% decrease in CL in the H group compared to controls. The overarching goal of this study using the neonatal Göttingen Minipig model was to disentangle the effects of systemic hypoxia and TH on PK, using four model drugs. Such insights can subsequently be used to inform and develop a physiologically-based pharmacokinetic (PBPK) model, which is useful for drug exposure prediction in human neonates.
PubMed: 38906699
DOI: 10.1124/dmd.124.001677 -
Journal of Veterinary Internal Medicine Jun 2024Factors affecting serum concentrations of levetiracetam in dogs are unknown and could affect the efficacy of levetiracetam in controlling seizures in dogs with epilepsy.
BACKGROUND
Factors affecting serum concentrations of levetiracetam in dogs are unknown and could affect the efficacy of levetiracetam in controlling seizures in dogs with epilepsy.
HYPOTHESIS/OBJECTIVES
Higher PO doses of levetiracetam will be needed in dogs to achieve serum concentrations shown to be effective in humans. Determine factors that could influence serum levetiracetam concentrations and justify dose adjustment in some epileptic dogs.
ANIMALS
Sixty-nine client-owned dogs with epilepsy treated with levetiracetam alone or in combination, based on 127 trough serum concentration measurements of levetiracetam.
METHODS
Retrospective cohort study. Linear mixed models were used to assess the effect of patient signalment and concurrent drug administration on serum concentrations of levetiracetam and the effect of serum concentration of levetiracetam on seizure frequency reduction.
RESULTS
The PO dose of levetiracetam significantly explained changes in serum levetiracetam concentration, and this causal link was stronger with monotherapy (R = 0.59, P < .001). Phenobarbital significantly decreased serum levetiracetam concentration in a dose dependent manner (R = 0.30, P = .003). Based on our model, a levetiracetam dosage of 99-216 mg/kg/day is necessary to obtain a serum levetiracetam concentration of 20 μg/mL when used alone or concurrently with 7 mg/kg/day of phenobarbital. No other factors were found to influence serum levetiracetam concentrations. No therapeutic range could be identified.
CONCLUSION AND CLINICAL IMPORTANCE
Our data suggest that a dosage of 99-216 mg/kg/day of levetiracetam is needed to achieve a serum concentration known to be therapeutically effective in humans, especially when administered concomitantly with phenobarbital.
PubMed: 38888491
DOI: 10.1111/jvim.17128 -
Frontiers in Veterinary Science 2024Zonisamide is used in dogs for the treatment of epileptic seizures. It is predominantly metabolised by CYP450 hepatic enzymes. When used concurrently with phenobarbital...
Zonisamide is used in dogs for the treatment of epileptic seizures. It is predominantly metabolised by CYP450 hepatic enzymes. When used concurrently with phenobarbital (PB), zonisamide clearance is increased and its elimination half-life decreases. However, the effect that zonisamide may have on serum PB concentrations in dogs has not been previously described. Eight dogs diagnosed with idiopathic epilepsy and two dogs with structural epilepsy commenced zonisamide at 8.0 mg/kg/12 h [7.4-10 mg/kg/12 h] following an increase in the frequency of epileptic seizures. Nine dogs were receiving PB every 12 h (4.2 mg/kg/12 h [3.8-6 mg/kg/12 h]), and one dog was receiving PB every 8 h (6 mg/kg/8 h). Following the addition of zonisamide and despite no increase in PB dosage, an increase in phenobarbital serum PB concentration was observed in 9 out of 10 dogs in subsequent measurements. In five dogs, phenobarbital serum concentrations were raised to concentrations higher than the reported hepatotoxic concentrations (trough>35 mg/L). This required a reduction in daily doses of PB. This case series suggests that zonisamide affects the metabolism of PB and causes an increase in PB serum concentrations over time.
PubMed: 38868500
DOI: 10.3389/fvets.2024.1389615 -
Frontiers in Pharmacology 2024Repeated and uncontrolled seizures in epilepsy result in brain cell loss and neural inflammation. Current anticonvulsants primarily target ion channels and receptors...
Repeated and uncontrolled seizures in epilepsy result in brain cell loss and neural inflammation. Current anticonvulsants primarily target ion channels and receptors implicated in seizure activity. Identification of neurotherapeutics that can inhibit epileptiform activity and reduce inflammation in the brain may offer significant benefits in the long-term management of epilepsy. Fenamates are unique because they are both non-steroidal anti-inflammatory drugs (NSAIDs) and highly subunit selective modulators of GABA receptors. In the current study we have investigated the hypothesis that fenamates have antiseizure properties using mature human stem cell-derived neuro-glia cell cultures, maintained in long-term culture, and previously shown to be sensitive to first, second and third generation antiepileptics. Mefenamic acid, flufenamic acid, meclofenamic acid, niflumic acid, and tolfenamic acid (each tested at 10-100 μM) attenuated 4-aminopyridine (4-AP, 100 μM) evoked epileptiform activity in a dose-dependent fashion. These actions were as effective diazepam (3-30 μM) and up to 200 times more potent than phenobarbital (300-1,000 μM). The low (micromolar) concentrations of fenamates that inhibited 4-AP evoked epileptiform activity correspond to those reported to potentiate GABA receptor function. In contrast, the fenamates had no effect on neural spike amplitudes, indicating that their antiseizure actions did not result from inhibition of sodium-channels. The antiseizure actions of fenamates were also not replicated by either of the two non-fenamate NSAIDs, ibuprofen (10-100 μM) or indomethacin (10-100 μM), indicating that inhibition of cyclooxygenases is not the mechanism through which fenamates have anticonvulsant properties. This study therefore shows for the first time, using functionally mature human stem cell-derived neuroglial circuits, that fenamate NSAIDs have powerful antiseizure actions independent of, and in addition to their well-established anti-inflammatory properties, suggesting these drugs may provide a novel insight and new approach to the treatment of epilepsy in the future.
PubMed: 38828453
DOI: 10.3389/fphar.2024.1385523 -
Iranian Journal of Allergy, Asthma, and... Apr 2024There are limited data on severe cutaneous adverse reactions (SCARs) associated with antiepileptic medications. The current study aims to investigate the clinical and...
BACKGROUND
There are limited data on severe cutaneous adverse reactions (SCARs) associated with antiepileptic medications. The current study aims to investigate the clinical and epidemiological characteristics of antiepileptic medication-induced SCARs in hospitalized children.
MATERIALS AND METHODS
The current five-year retrospective study was conducted at Isfahan University of Medical Sciences, Iran. This study included all children with a definite diagnosis of SCARs secondary to the use of antiepileptic medications based on the world health organization (WHO) definition. In our study SCARs were categorized into three fields: Hypersensitivity syndrome, drug reaction with eosinophilia and systemic symptoms (DRESS), and Stevens-Johnson syndrome (SJS)/toxic epidermal necrolysis (TEN).
RESULTS
Among 259 children with SCARs induced by antiepileptic medications, 199 (76.83%), 42 (16.22%), and 18 (6.95%) had hypersensitivity syndrome, DRESS, and SJS/TEN, respectively. Phenobarbital was the most common offending drug in all types of SCARs. The multinomial logistic regression model revealed that lymphadenopathy increased the occurrence of DRESS by 35 times compared to hypersensitivity syndrome (P < 0.001). Girls were at risk of SJS/TEN approximately 6 times more than boys (P = 0.027). Age (P = 0.021), weight (P = 0.036), and mucosal involvement (P < 0.001) affected the hospitalization duration in children with SCARs related to antiepileptic medication.
CONCLUSION
There are some similarities and differences in the clinical and epidemiological features of Iranian children suffering from antiepileptic medication-induced SCARs.
Topics: Humans; Anticonvulsants; Female; Male; Child; Retrospective Studies; Child, Preschool; Iran; Stevens-Johnson Syndrome; Drug Hypersensitivity Syndrome; Adolescent; Infant; Child, Hospitalized; Hospitalization; Risk Factors
PubMed: 38822509
DOI: 10.18502/ijaai.v23i2.15320 -
CNS Neuroscience & Therapeutics May 2024Synaptic vesicle protein 2A (SV2A) is a unique therapeutic target for pharmacoresistant epilepsy (PRE). As seizure-induced neuronal programmed death, parthanatos was...
AIMS
Synaptic vesicle protein 2A (SV2A) is a unique therapeutic target for pharmacoresistant epilepsy (PRE). As seizure-induced neuronal programmed death, parthanatos was rarely reported in PRE. Apoptosis-inducing factor (AIF), which has been implicated in parthanatos, shares a common cytoprotective function with SV2A. We aimed to investigate whether parthanatos participates in PRE and is mitigated by SV2A via AIF.
METHODS
An intraperitoneal injection of lithium chloride-pilocarpine was used to establish an epileptic rat model, and phenytoin and phenobarbital sodium were utilized to select PRE and pharmacosensitive rats. The expression of SV2A was manipulated via lentivirus delivery into the hippocampus. Video surveillance was used to assess epileptic ethology. Biochemical tests were employed to test hippocampal tissues following a successful SV2A infection. Molecular dynamic calculations were used to simulate the interaction between SV2A and AIF.
RESULTS
Parthanatos core index, PARP1, PAR, nuclear AIF and MIF, γ-H2AX, and TUNEL staining were all increased in PRE. SV2A is bound to AIF to form a stable complex, successfully inhibiting AIF and MIF nuclear translocation and parthanatos and consequently mitigating spontaneous recurrent seizures in PRE. Moreover, parthanatos deteriorated after the SV2A reduction.
SIGNIFICANCE
SV2A protected hippocampal neurons and mitigated epileptic seizures by inhibiting parthanatos via binding to AIF in PRE.
Topics: Animals; Rats; Apoptosis Inducing Factor; Male; Nerve Tissue Proteins; Disease Models, Animal; Rats, Sprague-Dawley; Drug Resistant Epilepsy; Membrane Glycoproteins; Hippocampus; Anticonvulsants
PubMed: 38801174
DOI: 10.1111/cns.14778 -
Clinical Case Reports Jun 2024Standardized alcohol withdrawal treatments, such as the phenobarbital taper protocol, are effective in the management of alcohol withdrawal syndromes associated with...
KEY CLINICAL MESSAGE
Standardized alcohol withdrawal treatments, such as the phenobarbital taper protocol, are effective in the management of alcohol withdrawal syndromes associated with surrogate alcohols including witch hazel toner.
ABSTRACT
Ingestion of alcohol not intended for consumption, also known as surrogate alcohols, is well-documented in patients with alcohol use disorder. Ingestion of surrogate alcohols may lead to higher morbidity and mortality than standard alcohol consumption alone. However, management of complications such as withdrawal syndromes in individuals consuming surrogate alcohols has received little attention in the literature. We present the case of a patient with alcohol use disorder who required medically supervised withdrawal following ingestion of witch hazel toner as a surrogate alcohol. Review of patient's history revealed routine ingestion of witch hazel toner as a substitute to traditional alcohols. Witch hazel toner is a non-FDA regulated product designed for topical use; it is commonly sold in a steam distilled formulation containing 13%-15% ethanol and small amounts of essential oil components, such as carvacrol and eugenol. During hospitalization the patient received treatment of alcohol withdrawal with a phenobarbital taper protocol and was discharged in stable condition. He also received resources for alcohol use disorder to follow-up in the outpatient setting. To our knowledge this is the first reported case of a patient requiring medically supervised withdrawal following ingestion of witch hazel toner and sheds light on the potential complications and management of patients who present following ingestion.
PubMed: 38799527
DOI: 10.1002/ccr3.9007 -
Toxicology Reports Jun 2024Phenobarbital is a long-acting barbiturate used to treat alcohol withdrawal and epilepsy. Acute overdoses present with varying levels of central nervous system...
Phenobarbital is a long-acting barbiturate used to treat alcohol withdrawal and epilepsy. Acute overdoses present with varying levels of central nervous system depression and large overdoses can be life threatening. Phenobarbital is an attractive candidate for enhanced elimination using urinary alkalinization given it is a weak acid with a long half-life and extensive urinary elimination. Limited human data exist regarding use of urine alkalinization for the treatment of phenobarbital overdose. We present a fourteen-year-old female who was treated with urinary alkalinization alone following an intentional ingestion of 3800 mg (84.4 mg/kg) of phenobarbital tablets. Urine drugs of abuse screening was preliminary positive for barbiturates and confirmed to be phenobarbital only. The initial serum phenobarbital concentration, drawn nine hours post-ingestion, was 97.4 mcg/ml (normal range 15-40 mcg/ml). Urinary alkalinization with sodium bicarbonate was started approximately 12 h post-ingestion and stopped at 72 h post-ingestion; clinical toxicity resolved by hospital day 5. The infusion was titrated to a urinary pH of greater than 7.5. Serial serum and urine phenobarbital measurements were obtained to determine elimination half-life and urinary excretion. The elimination half-life while undergoing urinary alkalinization was 81.3 h. Prior to initiation of urinary alkalinization, the urine phenobarbital concentration was 37 mcg/ml. Approximately 8.75 h after initiation, it was greater than 200 mcg/ml at a urine pH of 8.5. Urinary alkalinization appeared to augment urinary phenobarbital excretion, though with no discernible effect on elimination half-life and unclear clinical benefit. Further research is needed to better characterize the clinical effects of urinary alkalinization for phenobarbital overdose.
PubMed: 38798988
DOI: 10.1016/j.toxrep.2024.05.007 -
Frontiers in Medicine 2024Crigler-Najjar syndrome (CNS) is caused by mutations in uridine 5'-diphosphate glucuronyltransferase (UGT1A1) resulting in enzyme deficiency and hyperbilirubinemia. Type...
BACKGROUND
Crigler-Najjar syndrome (CNS) is caused by mutations in uridine 5'-diphosphate glucuronyltransferase (UGT1A1) resulting in enzyme deficiency and hyperbilirubinemia. Type II CNS patients could respond to phenobarbital treatment and survive. This study presents a rare case of type II CNS.
CASE SUMMARY
The proband was a 29-year-old male patient admitted with severe jaundice. A hepatic biopsy showed bullous steatosis of the peri-central veins of the hepatic lobule, sediment of bile pigment, and mild periportal inflammation with normal liver plate structure. The type II CNS was diagnosed by routine genomic sequencing which found that the proband with the Gry71Arg/Tyr486Asp compound heterozygous mutations in the UGT1A1 gene. After treatment with phenobarbital (180 mg/day), his bilirubin levels fluctuated between 100 and 200 μmol/L for 6 months and without severe icterus.
CONCLUSION
Type II CNS could be diagnosed by routine gene sequencing and treated by phenobarbital.
PubMed: 38784231
DOI: 10.3389/fmed.2024.1354514