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Trade names | Ecovia [1] |
Other names | (±)-2-amino-N-[1,2-di(phenyl)propan-2-yl]acetamide PR 934-423 |
Routes of administration | By mouth |
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Chemical and physical data | |
Formula | C17H20N2O |
Molar mass | 268.360 g·mol−1 |
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Remacemide is a drug which acts as a low-affinity NMDA antagonist with sodium channel blocking properties. [2] It has been studied for the treatment of acute ischemic stroke, [3] [4] epilepsy, [5] Huntington's disease, and Parkinson's disease.
Because remacemide has only a modest effect on seizure frequency and causes dizziness, it is no longer believed that remacemide will be an effective treatment for epilepsy. [6] Although no such statement has been made about remacemide's potential for treating stroke, Huntington's, or Parkinson's, remacemide is no longer being developed for these conditions.[ citation needed ]
Remacemide is also known as remacemide hydrochloride, (±)-2-amino-N-(1-methyl-1,2-diphenylethyl)-acetamide hydrochloride, or FPL 12924AA. [7]
Unlike many other treatments for epilepsy, remacemide does not appear to impair cognitive performance [9] [10] [5] or driving performance [11] in humans, although the evidence for effects on cognitive performance in animals has been mixed. [12] [13] [14] [15] [16] Remacemide is not a sedative. [17]
The median toxic dose of remacemide for neural impairment tests in mice is 5.6 mg/kg. [17] Its estimated median lethal dose is about 927.3 mg/kg in mice. [17] It has a favorable therapeutic index of 28.1 in mice. [17]
Remacemide delays the absorption of levodopa (300 mg of remacemide one hour before levodopa treatment delays mean time to peak levodopa plasma concentration by 20%) but not its total absorption (area-under-the-curve for levodopa plasma concentration was unchanged). [18]
Remacemide does not interact with sodium valproate, a treatment for epilepsy. [19]
Ramacemide does interact with carbamazepine. Remacemide inhibits the metabolism of carbamazepine, while carbamazepine induces the metabolism of remacemide and FPL 12495. [20]
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Remacemide is most commonly synthesized as the salt remacemide hydrochloride. However, there has been some investigation into other remacemide salts and their crystals, as different remacemide salts might taste more pleasant or have a solubility more suitable for a pediatric suspension formulation. [21]
Remacemide binds weakly and noncompetitively to the ionic channel site of the NMDA receptor complex. [7] Remacemide binds both allosterically and in the channel. [22] However, because remacemide binds so weakly to NMDAR, much of remacemide's in vivo effect against excitotoxicity is thought to be caused by its metabolic transformation to the more potent desglycine derivative FPL 12495. [7] That is, remacemide may actually act as a prodrug to deliver the active metabolite FPL 12495 to the central nervous system. [23]
In a well validated and described genetic model of absence epilepsy, rats of the WAG/Rij strain, remacemide and its metabolite FPL 12495 were found to have a common for glutamate antagonist usual effect on the number of spike/wave dischargesEEG, the drugs decrease spike/wave discharges dose dependently. However, in contrast to most other glutamate antagonists, FPL 12495 increased the duration of the spike-wave discharges. [24]
The brain uptake index (BUI), a measure of a drug's ability to pass the blood–brain barrier that involves the injection of radiolabeled test and reference substances into the common carotid artery of anesthetized animals, [25] [26] for remacemide is 51 ± 0.9 SD. [23]
The (-) stereoisomer of remacemide is of equal potency to the racemic mixture in preventing maximal electroshock seizures when administered orally to rats, while the (+)stereoisomer is less potent. [27]
Much of remacemide's effect in vivo is thought to be caused by the desglycine derivative FPL 12495 (±). [7] FPL 12495 (±) binds specifically and non-competitively to NMDAR. [28] Its effect on maximal electroconvulsive shock is more potent than remacemide. [7] The S isomer (FPL 12859) is even more potent than the racemic mixture, while the R isomer is less potent than the racemate. [7]
FPL 12495 is sometimes referred to as ARL 12495AA. [29] [30] [31]
FPL 15053 is the N-hydroxy-desglycinate of remacemide, and exhibits modest binding to NMDAR and modest effects on convulsions and mortality in test mice and rats. [7]
FPL 14331 and FPL 14465 are the p-hydroxy-desglycinates of remacemide, and they exhibit some efficacy against maximal electroconvulsive shock after i.p. and i.v. dosing. [7]
FPL 15455 is an oxoacetate metabolite of remacemide, but has no demonstrated biological activity. [7]
FPL 14991 and FPL 14981 are both β-Miydroxy-desglycinates of remacemide, and they display modest efficacy against maximal electroconvulsive shock in mice. [7] However FPL 14981 and not FPL 14991 prevents NMDLA-induced convulsions and mortality in mice. [7]
The hydroxy-methyl derivative of remacemide (FPL 13592) and its desglycinate (FPL 15112) prevents electric shock-induced convulsions only after i.v. administration; only the desglycine derivative binds to NMDAR. [7]
FPL 14467 (p-dihydroxy-desglycine) is inactive in vivo and weak in binding NMDAR. [7]
The values for 50% displacement of [3H]MK801 were 68 μM for remacemide and 0.48 μM for FPL 12495AA. [7]
Remacemide is an experimental drug most recently being developed by the British multinational pharmaceutical company AstraZeneca. However, there has been little news of its progress since 2000. A few sources indicate that its development has been discontinued. [32] [33]
Remacemide was one of the last drugs under development by the now-defunct English pharmaceutical company Fisons. [34] In 1995, it was acquired along with most of Fisons' research and development operations by the Swedish pharmaceutical company Astra, [35] which in 1999 merged with the British company Zeneca to form AstraZeneca. [36] In 2000, AstraZeneca considered possibly licensing out remacemide to some other pharmaceutical company, [37] but there has been little news about remacemide since then. Remacemide's development may have been discontinued in July 2001. [33]
In 1990, researchers at Fisons found that remacemide acted as an anticonvulsant in mice and rats [17] [27] . [38] Because of remacemide's potential as a neuroprotective agent through preventing glutamate toxicity, it was soon also under investigation as a treatment for Huntington's disease [39] and Parkinson's disease. [40]
By 1995, when Astra acquired remacemide, it was already in Phase IIb clinical development as an anti-epileptic drug [35] and Phase I clinical development as a treatment for Huntington's . [39] [41]
By 1998, when Astra announced its merger with Zeneca, remacemide had progressed to Phase III trials for epilepsy and Phase II trials for Parkinson's disease, and Astra was also investigating its potential for treating neuropathic pain [42]
In 1999, after the merger, AstraZeneca reported that they were investigating remacemide for its neuroprotective effects, and that they planned regulatory submissions for Huntington's disease in 2001 and for Parkinson's disease and epilepsy in 2003. [43]
Remacemide, under the trade name Ecovia, was designated an orphan drug for the treatment of Huntington's disease by the FDA in March 2000. [1]
Remacemide was last mentioned in AstraZeneca's reports on its R&D pipeline in 2000, when it was in Phase III clinical trials for remacemide in the treatment of Huntington's disease and Phase II for treatment of Parkinson's disease. At that time, the submission of the New Drug Application (NDA) to the FDA and the Marketing Authorization Application to the CHMP was projected for Huntington's in 2001 and for Parkinson's after 2003, [37] but there has been no news of such submission. In this report, it was also noted that remacemide was "under strategic review and a potential candidate for licensing activity" [37] (see this external article about drug licensing.)
There are no clinical trials of remacemide in progress, according to the Huntington Study Group, [44] and the Parkinson Study Group. [45]
Remacemide is an experimental drug not available to the public and not currently undergoing clinical trials.
Carbamazepine, sold under the brand name Tegretol among others, is an anticonvulsant medication used in the treatment of epilepsy and neuropathic pain. It is used as an adjunctive treatment in schizophrenia along with other medications and as a second-line agent in bipolar disorder. Carbamazepine appears to work as well as phenytoin and valproate for focal and generalized seizures. It is not effective for absence or myoclonic seizures.
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.
The N-methyl-D-aspartatereceptor (also known as the NMDA receptor or NMDAR), is a glutamate receptor and predominantly Ca2+ ion channel found in neurons. The NMDA receptor is one of three types of ionotropic glutamate receptors, the other two being AMPA and kainate receptors. Depending on its subunit composition, its ligands are glutamate and glycine (or D-serine). However, the binding of the ligands is typically not sufficient to open the channel as it may be blocked by Mg2+ ions which are only removed when the neuron is sufficiently depolarized. Thus, the channel acts as a "coincidence detector" and only once both of these conditions are met, the channel opens and it allows positively charged ions (cations) to flow through the cell membrane. The NMDA receptor is thought to be very important for controlling synaptic plasticity and mediating learning and memory functions.
Oxcarbazepine, sold under the brand name Trileptal among others, is a medication used to treat epilepsy. For epilepsy it is used for both focal seizures and generalized seizures. It has been used both alone and as add-on therapy in people with bipolar disorder who have had no success with other treatments. It is taken by mouth.
Clonazepam, sold under the brand name Klonopin among others, is a medication used to prevent and treat anxiety disorders, seizures, bipolar mania, agitation associated with psychosis, obsessive–compulsive disorder, and akathisia. It is a long-acting tranquilizer of the benzodiazepine class. It possesses anxiolytic, anticonvulsant, sedative, hypnotic, and skeletal muscle relaxant properties. It is typically taken orally but is also used intravenously. Effects begin within one hour and last between eight and twelve hours in adults.
In excitotoxicity, nerve cells suffer damage or death when the levels of otherwise necessary and safe neurotransmitters such as glutamate become pathologically high, resulting in excessive stimulation of receptors. For example, when glutamate receptors such as the NMDA receptor or AMPA receptor encounter excessive levels of the excitatory neurotransmitter, glutamate, significant neuronal damage might ensue. Excess glutamate allows high levels of calcium ions (Ca2+) to enter the cell. Ca2+ influx into cells activates a number of enzymes, including phospholipases, endonucleases, and proteases such as calpain. These enzymes go on to damage cell structures such as components of the cytoskeleton, membrane, and DNA. In evolved, complex adaptive systems such as biological life it must be understood that mechanisms are rarely, if ever, simplistically direct. For example, NMDA in subtoxic amounts induces neuronal survival of otherwise toxic levels of glutamate.
Amantadine, sold under the brand name Gocovri among others, is a medication used to treat dyskinesia associated with parkinsonism and influenza caused by type A influenzavirus, though its use for the latter is no longer recommended because of widespread drug resistance. It is also used for a variety of other uses. The drug is taken by mouth.
Dizocilpine (INN), also known as MK-801, is a pore blocker of the NMDA receptor, a glutamate receptor, discovered by a team at Merck in 1982. Glutamate is the brain's primary excitatory neurotransmitter. The channel is normally blocked with a magnesium ion and requires depolarization of the neuron to remove the magnesium and allow the glutamate to open the channel, causing an influx of calcium, which then leads to subsequent depolarization. Dizocilpine binds inside the ion channel of the receptor at several of PCP's binding sites thus preventing the flow of ions, including calcium (Ca2+), through the channel. Dizocilpine blocks NMDA receptors in a use- and voltage-dependent manner, since the channel must open for the drug to bind inside it. The drug acts as a potent anti-convulsant and probably has dissociative anesthetic properties, but it is not used clinically for this purpose because of the discovery of brain lesions, called Olney's lesions (see below), in laboratory rats. Dizocilpine is also associated with a number of negative side effects, including cognitive disruption and psychotic-spectrum reactions. It inhibits the induction of long term potentiation and has been found to impair the acquisition of difficult, but not easy, learning tasks in rats and primates. Because of these effects of dizocilpine, the NMDA receptor pore blocker ketamine is used instead as a dissociative anesthetic in human medical procedures. While ketamine may also trigger temporary psychosis in certain individuals, its short half-life and lower potency make it a much safer clinical option. However, dizocilpine is the most frequently used uncompetitive NMDA receptor antagonist in animal models to mimic psychosis for experimental purposes.
AP-7 is a selective NMDA receptor (NMDAR) antagonist that competitively inhibits the glutamate binding site and thus activation of NMDAR. It has anticonvulsant effects.
Memantine, sold under the brand name Axura among others, is a medication used to slow the progression of moderate-to-severe Alzheimer's disease. It is taken by mouth.
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.
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.
NMDA receptor antagonists are a class of drugs that work to antagonize, or inhibit the action of, the N-Methyl-D-aspartate receptor (NMDAR). They are commonly used as anesthetics for humans and animals; the state of anesthesia they induce is referred to as dissociative anesthesia.
Seletracetam is a pyrrolidone-derived drug of the racetam family that is structurally related to levetiracetam. It was under development by UCB Pharmaceuticals as a more potent and effective anticonvulsant drug to replace levetiracetam but its development has been halted.
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.
Safinamide, sold under the brand name Xadago, is a medication used as treatment for Parkinson's disease with "off" episodes; it has multiple modes of action, including the inhibition of monoamine oxidase B.
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.
Eslicarbazepine acetate (ESL), sold under the brand names Aptiom and Zebinix among others, is an anticonvulsant medication approved for use in Europe and the United States as monotherapy or as additional therapy for partial-onset seizures epilepsy.
Besonprodil (CI-1041) is a drug which acts as an NMDA antagonist, selective for the NR2B subunit. It is under development as a supplemental medication for Parkinson's disease, and has been shown in animals to be effective in counteracting the dyskinesias associated with long-term treatment with levodopa and related drugs.
Conantokins are a small family of helical peptides that are derived from the venom of predatory marine snails of the genus Conus. Conantokins act as potent and specific antagonists of the N-methyl-D-aspartate receptor (NMDAR). They are the only naturally-derived peptides to do so. The subtypes of conantokins exhibit a surprising variability of selectivity across the NMDAR subunits, and are therefore uniquely useful in developing subunit-specific pharmacological probes.