Suvorexant, a Novel Dual Orexin Receptor Antagonist, for the Management of Insomnia

Purpose of Review

The present investigation is a comprehensive review regarding the use of Suvorexant for insomnia treatment. It covers the background, pathophysiology, and significance of addressing insomnia, the pharmaceutical details of Suvorexant, and its safety, efficacy, and implications in treating insomnia. We further discuss Suvorexant's role in targeting insomnia with other comorbidities.

Recent Findings

Insomnia refers to poor quality and/or quantity of sleep. While there are many existing treatments such as benzodiazepines, melatonin agonists, TCAs, and atypical antipsychotics used to target various receptors involved in normal induction and maintenance of sleep, Suvorexant is an antagonist that specifically targets orexin receptors. Recent clinical studies suggest that Suvorexant is both clinically safe and effective. Quantity and quality of sleep are measured in various ways, yet the consensus points towards Suvorexant's effectiveness in improving sleep time, onset, latency, and quality compared to placebo. In addition to helping improve isolated insomnia, Suvorexant helps improve sleep in patients that have other comorbidities such as obstructive sleep apnea, Alzheimer's disease, dementia, acute stroke, and delirium. While Suvorexant is safe, there are still adverse effects associated with the drug that needs to be considered. The most common adverse effects include dizziness, somnolence, headaches, and cognitive impairment.

Summary

Insomnia is a major public health concern that affects many people worldwide and has been linked to many adverse health outcomes. While there are existing treatments that target different receptors and pathways of normal sleep induction and maintenance, Suvorexant is a novel drug that targets dual orexin receptors. Its safety and efficacy, mechanism of action, pharmacokinetic parameters, and relative lack of rebound and withdrawal effects render suvorexant a reliable choice for the treatment of insomnia.

Glossopharyngeal Neuralgia: Epidemiology, Risk factors, Pathophysiology, Differential diagnosis, and Treatment Options

Purpose of Review

This is a comprehensive review of the most recent literature on glossopharyngeal neuralgia (GPN), a relatively rare form of neuropathic facial pain. It covers the epidemiology, risk factors, pathophysiology, and differential diagnosis given that glossopharyngeal neuralgia can often be confused with other facial pain syndromes. Finally, we extensively review recent findings regarding medical or conservative measures, minimally invasive, and surgical options for potentially treating and managing glossopharyngeal neuralgia.

Recent Findings

An in-depth analysis of the recent literature indicates that glossopharyngeal neuralgia is not only rare but its etiology and pathophysiology are complex and are often secondary to other disease processes. Regardless, current management options are shown to be effective in controlling pain. Conservatively, first-line management of GPN is carbamazepine, but gabapentin and eslicarbazepine acetate are suitable alternatives. In terms of current minimally invasive pain management techniques, pulsed radiofrequency ablation, nerve blocks, or percutaneous radiofrequency thermocoagulation are effective. Finally, surgical management involves microvascular decompression and rhizotomy.

Summary

While there are currently many viable options for addressing glossopharyngeal neuralgia pain ranging from conservative to surgical management, the complex nature of GPN etiology, pathophysiology, and involved anatomical structures prompts further research for more effective ways to treat the disease.

deutetrabenazine for the treatment of chorea associated with Huntington's disease

This is a comprehensive review of the literature regarding the use of Deutetrabenazine in treating chorea associated with Huntington's disease. Unfortunately, treatment has been limited for many aspects of this neurodegenerative disease. The present investigation presents the background, evidence, and indications for the use Deutetrabenazine in the setting of Huntington's disease. Huntington's disease is characterized by a variety of motor, psychiatric, and cognitive symptoms with chorea being one of the more notable ones. Chorea is a movement disorder present in multiple neurologic diseases that causes involuntary and irregular muscle movements theorized to be stemming from high dopamine levels. Deutetrabenazine is thought to function as an inhibitor of the VMAT2 vesicular monoamine transporter resulting in decreased monoamine release, including dopamine, in the synaptic cleft which has a therapeutic effect in management of chorea. This drug was approved by the FDA in 2017 with a specific indication for tardive dyskinesia and choreiform movement in Huntington's disease. Currently, there is no definitive treatment for Huntington's disease. Thus, management is primarily focused on symptom management with the use of a variety of pharmaceutical agents. Chorea is one of the many manifestations that significantly alter the quality of life of many patients. Deutetrabenazine is a promising new option for the treatment of chorea in the setting of Huntington's disease. Although studies so far have displayed mixed results, further research, including head-to-head studies, is necessary to elucidate the true potential of this drug.

pitolisant, a novel histamine-3 receptor competitive antagonist, and inverse agonist, in the treatment of excessive daytime sleepiness in adult patients with narcolepsy

Narcolepsy is a debilitating sleep disorder that presents with excessive daytime sleepiness (EDS) and cataplexy, which is a sudden paralysis of muscle tone triggered by strong emotions such as laughing. It is also associated with many other disorders, including psychiatric disorders, neurologic illnesses, and medication side effects. Common causes of delayed and incorrect diagnoses of these conditions include lack of physician familiarity with narcolepsy symptoms and comorbidities which mask narcolepsy signs and symptoms. Current pharmacologic therapies include Modafinil and Armodafinil for EDS and sodium oxybate for cataplexy. This review discusses the epidemiology, pathophysiology, risk factors, presentation, treatment of narcolepsy, and the role of a novel drug, Pitolisant, in the treatment of EDS in adults with narcolepsy. Pitolisant is a histamine-3 receptor (H3R), competitive antagonist, and inverse agonist, acting through the histamine system to regulate wakefulness. It is a novel drug approved in August 2019 by the FDA, is not classified as a controlled substance, and is approved for use in Europe and the United States to treat EDS and cataplexy in narcolepsy. Recent phase II and III trials have shown that Pitolisant helps reduce the ESS score and cataplexy. In summary, based on comparative studies, recent evidence has shown that Pitolisant is non-inferior to Modafinil in the treatment of EDS but superior to Modafinil in reducing cataplexy.

Risdiplam for the Use of Spinal Muscular Atrophy

Spinal muscular atrophy (SMA) is one of the leading causes of death in infants related to the degeneration of neurons. Currently, there are no curative treatment options for SMA, and many options available may not be feasible. This review presents the background, clinical studies, and indications for the use of Risdiplam in treating SMA. SMA causes a decrease in the production of survival motor neuron proteins (SMN) and current treatments target to increase the expression of SMN. Risdiplam is the first and only oral medication to be approved to treat SMA. As an SMN2 splicing modifier, it has provided stronger systemic therapies than previous intrathecal and gene replacement therapies. There have been many efforts to treat SMA with multidisciplinary approaches. These include intrathecal injections to gene replacement therapies. However, these have been faced with limitations such as reaching a good therapeutic dose in systemic tissues, route of administration, and price. Risdiplam is currently the only orally administered drug approved by the FDA for the treatment of SMA. It not only provides a good therapeutic window to systemic tissues but allows for a non-invasive approach in infants. Further investigation and comparison on the safety profile of Risdiplam due to its broader systemic effect should be considered with other available therapies.