Clinical data | |
---|---|
Routes of administration | Oral [1] [2] |
ATC code |
|
Legal status | |
Legal status |
|
Pharmacokinetic data | |
Bioavailability | >90% [1] [2] |
Elimination half-life | 8 hours [1] [2] |
Identifiers | |
| |
CAS Number | |
PubChem CID | |
ChemSpider | |
UNII | |
KEGG | |
CompTox Dashboard (EPA) | |
Chemical and physical data | |
Formula | C10H14F2N2O |
Molar mass | 216.232 g·mol−1 |
3D model (JSmol) | |
| |
| |
(what is this?) (verify) |
Seletracetam (UCB 44212) is a pyrrolidone-derived [2] drug of the racetam family that is structurally related to levetiracetam (trade name Keppra). [2] [3] It was under development by UCB Pharmaceuticals as a more potent and effective anticonvulsant drug to replace levetiracetam but its development has been halted. [1]
There are two main mechanisms of action for seletracetam. The first is its high-affinity stereospecific binding to synaptic vesicle glycoprotein 2A (SV2A). [2] [3] Seletracetam has shown potent seizure suppression in models of acquired and genetic epilepsy, [3] and has been well tolerated by various animal models. [3] The second is its binding to N-type calcium channels and preventing influx of Ca2+ during high-voltage activation that is typical of epilepsy. [4] [5] [6]
While similar in structure to nootropic drugs, it is not expected to have cognitive enhancing properties. [7] Seletracetam was in Phase II clinical trials under the supervision of the U.S. Food and Drug Administration (FDA) but its production is on hold. [3]
Seletracetam's molecular structure contains elements common to other anticonvulsants, including levetiracetam and brivaracetam, such as a nitrogen heterocyclic system. [8] [9] Like brivaracetam, seletracetam is a derivative of levetiracetam.
Structure and activity relationship studies have concluded that the most potent anticonvulsant activity was at the amide nitrogen atom and that this activity was further enhanced by nearby electronegative functional groups such as the di-fluoro group on seletracetam. [10]
Seletracetam is an orally administered drug, after which it is quickly and efficiently absorbed. [2] The typical dosage is 0.03–10 mg/kg per day (up to 0.6g per day). [1]
Seletracetam's anti-epileptic effects are due to its high affinity binding to synaptic vesicle glycoprotein 2A (SV2A) [1] [2] [3] —part of a calcium ion regulator. The SV2A protein assists with the coordination of synaptic vesicle exocytosis, [11] [12] which induces neurotransmitter release in the presence of an influx in Ca2+. A correlation has been drawn between the binding affinity of seletracetam (and its analogues) to SV2A and the degree of seizure prevention in animal models. [7] [11] [13]
In addition, studies of ion currents have shown that seletracetam significantly decreases the amount of high-voltage derived Ca2+ currents [4] which have been implicated in causing the high intracellular Ca2+ influx during epileptic activity. [5] It is thought that seletracetam binds to N-type Ca2+ channels and inhibits their ability to allow calcium ions to enter the cell, [4] [5] although the drug does not bind to T-type channels that mediate low-voltage activated Ca2+ currents. [2] [14] Seletracetam thereby decreases cellular excitation, but it does not seem to affect voltage-gated Na+ or K+ currents. [4] Selectracetam has been demonstrated to not significantly affect currents gated by NMDA, AMPA, GABA, glycine, or kainic acid. [15]
The dual effect of seletracetam is an overall decrease in the amount of Ca2+ influx in the cell during an action potential due to binding at N-type channels, which prevents over-excitation of the neuron, as well as a decrease in neurotransmitter release as a product of cellular excitation due to the interaction of the drug with SV2A, which reduces the spread of excitation to nearby cells. [6]
Compared to levetiracetam, which binds at the same site, [11] seletracetam binds to SV2A with ten times higher affinity. [7] [13]
The nature of why the seletracetam molecule binds so specifically to SV2A and how SV2A affects exocytosis is unclear. [16]
The oral bioavailability of seletracetam is >90% [2] and its half-life is approximately 8 hours. [1] [2] 25% of ingested seletracetam is metabolized and excreted unchanged and about 53% is excreted in the form of an inactive carboxylic acid metabolite. [11] [14] The main metabolic mechanism is the hydrolysis of an acetamide to a carboxylic acid. [14] [17]
Seletracetam exhibits first-order mono-compartmental pharmacokinetics, in which there is a simple linear relationship between the amount of drug that was administered, the time that has passed, and the amount of drug subsequently remaining in the body. [2] This contrasts the nonlinear pharmacokinetics typical of previously available anticonvulsants such as phenobarbital, phenytolin, valproate and carbamazepine. [2] The benefit of linear kinetics is that the steady-state concentration of the drug is directly and reliably related to the dose of the drug that is administered; this allows for simple and reliable dose adjustments.
In vitro studies performed in rodent hippocampal slices found that seletracetam causes a complete reversal of the increases in activity of population spike amplitude in epilepsy models. [7] These reductions in in vitro epilepsy symptoms were present at extracellular concentrations of 3.2 μM. [7] This is approximately 10% of the most effective concentration of levetiracetam in similar tests. [18]
Seletracetam has been tested on various animal models for epilepsy, with mixed results.
Unlike drugs that act on voltage-gated sodium channels, [19] seletracetam was demonstrated to have no significant effect on the maximal electroshock seizure test results in mice. [7] It similarly had no relieving effects in mice of the other most common acute seizure model, the pentylenetetrazol convulsion-induction model. [2] [7] [14]
Seletracetam did, however, show promising results in acquired and genetic epilepsy models. [2] [7] In the mouse model of corneal kindling, which exhibits the anticonvulsant capability of generalized motor seizures, doses as low as 0.07 mg/kg intraperitoneal injection (i.p.), and ED50 of 0.31 mg/kg i.p. were effective. [7] Occurrence of audiogenic seizures—those induced by white noise—in mice were also significantly reduced by an ED50 of 0.17 mg/kg i.p., which suggests that selectracetam reduces convulsions caused by clonic seizures. [7]
In hippocampal kindling model rats, seizure severity was significantly reduced by seletracetam oral doses of 0.23 mg/kg. This provides further evidence of the potential benefits of selectracetam on generalized motor seizures. [7] Seletracetam also performed well as a method to reduce the suppression of spontaneous spike-and-wave discharges that are often associated with absence epilepsy activity. [20] This was demonstrated by its effect on Strasbourg genetic absence epilepsy rats (GAERS). [21] This model had an ED50 of 0.15 mg/kg i.p. [7]
Rodents were found to have negligible behavioral deficits as a result of seletracetam administration, as measured by performance on a rotarod task. [7] [22]
Unlike currently prescribed anticonvulsants such as phenytoin, valproate, and phenobarbital, seletracetam shows few central nervous system (CNS) side effects and is predicted to have low levels of drug-drug interactions due to its low binding (<10%) to plasma proteins. [2] [23] There have been, however, no formal studies conducted on drug-drug interactions with seletracetam. [11]
Other than SV2A and the high-voltage-activated Ca2+ channels, seletracetam does not significantly bind to other CNS receptors, ion channels, or uptake mechanisms. [11] Seletracetam has, however, shown a slight selectivity for glycine receptors. [11] [14] [24] This drug neither inhibits nor unnecessarily induces the action of any major human metabolizing enzymes, which further reduces adverse effects. [23]
Early data from phase I trials were optimistic, and found seletracetam to be well tolerated by human volunteers. [25]
In phase II trials side effects were limited to the CNS in origin, were of mild to moderate severity, and most were resolved within 24 hours [2] and with no medical intervention. [11] The most frequently reported adverse effects of seletracetam were dizziness, feeling drunk, euphoria, nausea, and somnolence. [11]
Seletracetam was well tolerated by healthy individuals after single oral doses ranging from 2 to 600 mg, as well as after b.i.d. (twice daily) doses of 200 mg. [11] Toxicology studies have shown that this drug has low acute oral toxicity and no significant negative effects on the CNS, cardiac, or respiratory systems. [11] High doses of 2000 mg/kg per day (in mice and rats) and greater than 600 mg/kg per day (in dogs) were poorly tolerated. [11]
Phase II clinical trials of seletracetam were ongoing but in July 2007 the company stated that the drug's development has been put on hold. [3] Although the conducted Phase II trials showed success, it was less than expected given the performance of seletracetam in animal models. [1] There have been no known Phase IIb or Phase III trials. [3]
In 2010, development of seletracetam was halted in favor of the development of brivaracetam, a newer variation of the drug. [1]
Phenytoin (PHT), sold under the brand name Dilantin among others, is an anti-seizure medication. It is useful for the prevention of tonic-clonic seizures and focal seizures, but not absence seizures. The intravenous form, fosphenytoin, is used for status epilepticus that does not improve with benzodiazepines. It may also be used for certain heart arrhythmias or neuropathic pain. It can be taken intravenously or by mouth. The intravenous form generally begins working within 30 minutes and is effective for roughly 24 hours. Blood levels can be measured to determine the proper dose.
Anticonvulsants are a diverse group of pharmacological agents used in the treatment of epileptic seizures. Anticonvulsants are also increasingly being used in the treatment of bipolar disorder and borderline personality disorder, since many seem to act as mood stabilizers, and for the treatment of neuropathic pain. Anticonvulsants suppress the excessive rapid firing of neurons during seizures. Anticonvulsants also prevent the spread of the seizure within the brain.
Topiramate, sold under the brand name Topamax among others, is a medication used to treat epilepsy and prevent migraines. It has also been used in alcohol dependence and essential tremor. For epilepsy this includes treatment for generalized or focal seizures. It is taken orally.
Lamotrigine, sold under the brand name Lamictal among others, is a medication used to treat epilepsy and stabilize mood in bipolar disorder. For epilepsy, this includes focal seizures, tonic-clonic seizures, and seizures in Lennox-Gastaut syndrome. In bipolar disorder, lamotrigine has not been shown to reliably treat acute depression for all groups except the severely depressed group; but for patients with bipolar disorder who are not currently symptomatic, it appears to be effective in reducing the risk of future episodes of depression.
The α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptor (also known as AMPA receptor, AMPAR, or quisqualate receptor) is an ionotropic transmembrane receptor for glutamate (iGluR) and predominantly Na+ ion channel that mediates fast synaptic transmission in the central nervous system (CNS). It has been traditionally classified as a non-NMDA-type receptor, along with the kainate receptor. Its name is derived from its ability to be activated by the artificial glutamate analog AMPA. The receptor was first named the "quisqualate receptor" by Watkins and colleagues after a naturally occurring agonist quisqualate and was only later given the label "AMPA receptor" after the selective agonist developed by Tage Honore and colleagues at the Royal Danish School of Pharmacy in Copenhagen. The GRIA2-encoded AMPA receptor ligand binding core (GluA2 LBD) was the first glutamate receptor ion channel domain to be crystallized.
Levetiracetam, sold under the brand name Keppra among others, is a medication used to treat epilepsy. It is used for partial-onset, myoclonic, or tonic–clonic seizures and is taken either by mouth as an immediate or extended release formulation or by injection into a vein.
Piracetam is a drug that has efficacy in cognitive disorders, vertigo, cortical myoclonus, dyslexia, and sickle cell anemia; sources differ on its usefulness for dementia. Piracetam is sold as a medication in many European countries. Sale of piracetam is not illegal in the United States, although it is not regulated nor approved by the FDA, so it is legally sold for research use only.
Clonazepam, sold under the brand names Klonopin and Rivotril, is a medication used to prevent and treat anxiety disorders, seizures, bipolar mania, agitation associated with psychosis, OCD and akathisia. It is a tranquilizer of the benzodiazepine class. It possesses anxiolytic, anticonvulsant, sedative, hypnotic, and skeletal muscle relaxant properties. It is typically taken by mouth but is also used intravenously. Effects begin within one hour and last between six and twelve hours.
Tiagabine is an anticonvulsant medication produced by Cephalon that is used in the treatment of epilepsy. The drug is also used off-label in the treatment of anxiety disorders and panic disorder.
Primidone, sold under various brand names, is a barbiturate medication that is used to treat partial and generalized seizures and essential tremors. It is taken by mouth.
Clobazam, sold under the brand names Frisium, Onfi and others, is a benzodiazepine class medication that was patented in 1968. Clobazam was first synthesized in 1966 and first published in 1969. Clobazam was originally marketed as an anxioselective anxiolytic since 1970, and an anticonvulsant since 1984. The primary drug-development goal was to provide greater anxiolytic, anti-obsessive efficacy with fewer benzodiazepine-related side effects.
Felbamate is an anticonvulsant used in the treatment of epilepsy. It is used to treat partial seizures in adults and partial and generalized seizures associated with Lennox–Gastaut syndrome in children. However, an increased risk of potentially fatal aplastic anemia and/or liver failure limit the drug's usage to severe refractory epilepsy.
Brivaracetam, sold under the brand name Briviact among others, is a chemical analog of levetiracetam, a racetam derivative with anticonvulsant (antiepileptic) properties. It is marketed by the pharmaceutical company UCB.
Lacosamide, sold under the brand name Vimpat among others, is a medication used for the treatment of partial-onset seizures and primary generalized tonic-clonic seizures. It is used by mouth or intravenously.
Synaptic vesicle glycoprotein 2A is a ubiquitous synaptic vesicle protein that in humans is encoded by the SV2A gene. The protein is targeted by the anti-epileptic drugs (anticonvulsants) levetiracetam and brivaracetam.
Remacemide is a drug which acts as a low-affinity NMDA antagonist with sodium channel blocking properties. It has been studied for the treatment of acute ischemic stroke, epilepsy, Huntington's disease, and Parkinson's disease.
A GABA reuptake inhibitor (GRI) is a type of drug which acts as a reuptake inhibitor for the neurotransmitter gamma-Aminobutyric acid (GABA) by blocking the action of the gamma-Aminobutyric acid transporters (GATs). This in turn leads to increased extracellular concentrations of GABA and therefore an increase in GABAergic neurotransmission. Gamma-aminobutyric acid (GABA) is an amino acid that functions as the predominant inhibitory neurotransmitter within the central nervous system, playing a crucial role in modulating neuronal activity in both the brain and spinal cord. While GABA predominantly exerts inhibitory actions in the adult brain, it has an excitatory role during developmental stages. When the neuron receives the action potential, GABA is released from the pre-synaptic cell to the synaptic cleft. After the action potential transmission, GABA is detected on the dendritic side, where specific receptors collectively contribute to the inhibitory outcome by facilitating GABA transmitter uptake. Facilitated by specific enzymes, GABA binds to post-synaptic receptors, with GABAergic neurons playing a key role in system regulation. The inhibitory effects of GABA diminish when presynaptic neurons reabsorb it from the synaptic cleft for recycling by GABA transporters (GATs). The reuptake mechanism is crucial for maintaining neurotransmitter levels and synaptic functioning. Gamma-aminobutyric acid Reuptake Inhibitors (GRIs) hinder the functioning of GATs, preventing GABA reabsorption in the pre-synaptic cell. This results in increased GABA levels in the extracellular environment, leading to elevated GABA-mediated synaptic activity in the brain.
Retigabine (INN) or ezogabine (USAN) is an anticonvulsant used as an adjunctive treatment for partial epilepsies in treatment-experienced adult patients. The drug was developed by Valeant Pharmaceuticals and GlaxoSmithKline. It was approved by the European Medicines Agency under the trade name Trobalt on March 28, 2011, and by the United States Food and Drug Administration (FDA), under the trade name Potiga, on June 10, 2011. Production was discontinued in June 2017.
Talampanel is a drug which has been investigated for the treatment of epilepsy, malignant gliomas, and amyotrophic lateral sclerosis (ALS).
Lomerizine (INN) is a diphenylpiperazine class L-type and T-type calcium channel blocker. This drug is currently used clinically for the treatment of migraines, while also being used experimentally for the treatment of glaucoma and optic nerve injury.