Daridorexant (Quviviq™; Idorsia Pharmaceuticals Ltd.) is an orally administered dual orexin type 1 and type 2 (OX1 and OX2) receptor antagonist (DORA) being developed for the treatment of insomnia. It was selected from a pool of drug candidates on the basis of an expected effect duration of ≈ 8 h at a dose of 25 mg, with a half-life intended to minimize residual effects that might impair daytime functioning. Based on the results of two pivotal phase III trials, daridorexant was recently approved in the USA for the treatment of adult patients with insomnia characterized by difficulties with sleep onset and/or sleep maintenance. The mechanism of action of daridorexant in the treatment of insomnia is presumed to be through antagonism of orexin receptors. The orexin neuropeptide signaling system plays a role in wakefulness. Blocking the binding of wake-promoting neuropeptides orexin A and orexin B to receptors OX1R and OX2R is thought to suppress wake drive.

Ganaxolone (3alpha-hydroxy-3beta-methyl-5alpha-pregnan-20-one) (GNX) is the 3beta-methylated synthetic analog of allopregnanolone; it belongs to a class of compounds referred to as neurosteroids. GNX is an allosteric modulator of GABA(A) receptors acting through binding sites which are distinct from the benzodiazepine binding site. It has activity in a broad range of animal models of epilepsy. GNX has been shown to be well tolerated in adults and children. In early phase II studies, GNX has been shown to have activity in adult patients with partial-onset seizures and epileptic children with history of infantile spasms. It is currently undergoing further development in infants with newly diagnosed infantile spasms, in women with catamenial epilepsy, and in adults with refractory partial-onset seizures. Ganaxolone is a CNS-selective GABAA modulator being developed in three different dose forms (IV, capsule, and liquid) intended to maximize therapeutic reach to adult and pediatric patients in both acute and chronic care settings.Ganaxolone is a synthetic analog of endogenous allopregnanolone, which has been shown to be an effective anticonvulsant by restoring electrical balance to the seizing brain. While allopregnanolone’s anticonvulsant and anti-anxiety activities are well documented, allopregnanolone has the potential to convert back to its metabolic precursor progesterone, which could lead to hormonal side effects. Ganaxolone has been designed with an added methyl group that prevents back conversion to an active steroid which unlocks ganaxolone’s potential for chronic use. In preclinical studies, ganaxolone exhibited potency and efficacy comparable to allopregnanolone. Both ganaxolone and allopregnanolone bind to GABAA at the synaptic and extrasynaptic binding sites. Activity with extrasynaptic GABAA receptors are of particular importance for treating patients who developed tolerance to benzodiazepines and barbiturates. Ganaxolone binds to the GABAA receptors, which opens the pore to allow chloride ions to move into the postsynaptic neuron, leading to the inhibition of neurotransmission.

Remimazolam is an intravenous benzodiazepine sedative-hypnotic with rapid onset and offset of action. This compound undergoes organ-independent metabolism to an inactive metabolite. Like other benzodiazepines, remimazolam can be reversed with flumazenil to rapidly terminate sedation and anesthesia. Phase I and II clinical trials have shown that remimazolam is safe and effective when used for procedural sedation. Phase III clinical trials have been completed investigating efficacy and safety in patients undergoing bronchoscopy and colonoscopy. The developer of this drug has suggested that intensive care unit sedation (beyond 24 hours) could be another possible indication for further development, since it is unlikely that prolonged infusions or higher doses of remimazolam would result in accumulation and extended effect.

Cenobamate (also known as YKP3089) is a small molecule sodium channel blocker in development for the treatment of partial-onset seizures in adult patients. In mice and rats, Cenobamate displayed an anticonvulsant activity in the maximal electroshock test and prevented seizures induced by chemical convulsants such as pentylenetetrazol and picrotoxin. In addition, Cenobamate was reported to be effective in two models of focal seizure, the hippocampal kindled rat and the mouse 6 Hz psychomotor seizure models. Two completed adequate and well-controlled clinical studies demonstrated a significant reduction in focal seizures with Cenobamate in patients with epilepsy, and a long-term open-label phase 3 safety clinical trial is currently ongoing. Cenobamate is considered a new generation antiepileptic therapy and clinical trials have shown that it may be more effective and safer than existing drugs. If licensed, Cenobamate will offer a new adjunctive treatment option for patients with partial focal epilepsy.

Lacosamide is an anticonvulsant that is FDA approved for the treatment of partial-onset seizures. The precise mechanism by which lacosamide exerts its antiepileptic effects in humans remains to be fully elucidated. In vitro electrophysiological studies have shown that lacosamide selectively enhances slow inactivation of voltage-gated sodium channels, resulting in stabilization of hyperexcitable neuronal membranes and inhibition of repetitive neuronal firing Common adverse reactions include diplopia, headache, dizziness, nausea. Patients with renal or hepatic impairment who are taking strong inhibitors of CYP3A4 and CYP2C9 may have a significant increase in exposure to Lacosamide tablets.

Pregabalin, marketed under the brand name Lyrica among others. LYRICA is indicated for: Neuropathic pain associated with diabetic peripheral neuropathy (DPN) Postherpetic neuralgia (PHN); Adjunctive therapy for adult patients with partial onset seizures; Fibromyalgia; Neuropathic pain associated with spinal cord injury. It has been shown the clinical effects of pregabalin are likely due to direct and selective interactions with α(2)δ-1 and α(2)δ-2 subunits of voltage-gated calcium channels. While pregabalin is a structural derivative of the inhibitory neurotransmitter gamma aminobutyric acid (GABA), it does not bind directly to GABAA, GABAB, or benzodiazepine receptors, does not augment GABAA responses in cultured neurons, does not alter rat brain GABA concentration or have acute effects on GABA uptake or degradation. However, in cultured neurons prolonged application of pregabalin increases the density of GABA transporter protein and increases the rate of functional GABA transport. Pregabalin does not block sodium channels, is not active at opiate receptors, and does not alter cyclooxygenase enzyme activity. It is inactive at serotonin and dopamine receptors and does not inhibit dopamine, serotonin, or noradrenaline reuptake.

Oliceridine (TRV-130) is a potent μ-opioid receptor agonist. In cell-based assays, TRV130 elicits robust G protein signaling, with potency and efficacy similar to morphine, but with far less β-arrestin recruitment and receptor internalization. In rodents, TRV130 is potently analgesic while causing less gastrointestinal dysfunction and respiratory suppression than morphine at equianalgesic doses. Oliceridine is being developed by Trevena for the first-line treatment of moderate-to-severe acute postoperative pain. Phase III development is underway for the treatment of postoperative pain in the US. Phase II development is underway for the treatment of acute pain in the US.

Ezogabine (U.S. adopted name) or retigabine (international nonproprietary name) is one of a family of aminopyrroles with anticonvulsant activity. It is used as an adjunctive treatment for partial epilepsies in treatment-experienced adult patients. The drug was approved by the European Medicines Agency under the trade name Trobalt and by the United States Food and Drug Administration (FDA), under the trade name Potiga. The mechanism by which ezogabine exerts its therapeutic effects has not been fully elucidated. In vitro studies indicate that ezogabine enhances transmembrane potassium currents mediated by the KCNQ (Kv7.2 to 7.5) family of ion channels. By activating KCNQ channels, ezogabine is thought to stabilize the resting membrane potential and reduce brain excitability. This mechanism of action is unique among antiepileptic drugs, and may hold promise for the treatment of other neurologic conditions, including migraine, tinnitus and neuropathic pain. In vitro studies suggest that ezogabine may also exert therapeutic effects through augmentation of GABA-mediated currents.

Pyrovalerone is a psychostimulant. It has a central action. Pyrovalerone inhibits the dopamine transporter and the norepinephrine transporter, and is a weak inhibitor of the serotonin transporter. Pyrovalerone was demonstrated to reduce symptoms of chronic fatigue in humans. It stimulated locomotor activity in mice. Though pyrovalerone is still occasionally prescribed, it is used infrequently due to problems with abuse and dependence. Side effects of pyrovalerone include anxiety, fragmented sleep or insomnia and trembling, shaking or muscle tremors.

Pyrovalerone is a psychostimulant. It has a central action. Pyrovalerone inhibits the dopamine transporter and the norepinephrine transporter, and is a weak inhibitor of the serotonin transporter. Pyrovalerone was demonstrated to reduce symptoms of chronic fatigue in humans. It stimulated locomotor activity in mice. Though pyrovalerone is still occasionally prescribed, it is used infrequently due to problems with abuse and dependence. Side effects of pyrovalerone include anxiety, fragmented sleep or insomnia and trembling, shaking or muscle tremors.