Mechanism of action
Alprazolam is classed as a high-potency triazolobenzodiazepine: a benzodiazepine with a triazole ring attached to its structure. As a benzodiazepine, alprazolam produces a variety of therapeutic and adverse effects by binding to the GABAA benzodiazepine receptor site and modulating its function; GABA receptors are the most prolific inhibitory receptor within the brain. The GABA chemical and receptor system mediates inhibitory or calming effects of alprazolam on the nervous system. Binding of alprazolam to the GABAA receptor, a chloride ion channel, enhances the effects of GABA, a neurotransmitter. When GABA binds the GABAA receptor the channel opens and chloride enters the cell which makes it more resistant to depolarisation. Therefore, alprazolam has a depressant effect on synaptic transmission to reduce anxiety.The GABAA receptor is made up of 5 subunits out of a possible 19, and GABAA receptors made up of different combinations of subunits have different properties, different locations within the brain, and, importantly, different activities with regard to benzodiazepines. Alprazolam and other triazolobenzodiazepines such as triazolam that have a triazole ring fused to their diazepine ring appear to have antidepressant properties. This is perhaps due to the similarities shared with tricyclic antidepressants, as they have two benzene rings fused to a diazepine ring. Alprazolam causes a marked suppression of the hypothalamic–pituitary–adrenal axis. The therapeutic properties of alprazolam are similar to other benzodiazepines and include anxiolytic, anticonvulsant, muscle relaxant, hypnotic and amnesic; however, it is used mainly as an anxiolytic.
Solriamfetol also differs from amphetamines as it does not promote the release of norepinephrine in the brain.Narcolepsy has sometimes been treated with selective serotonin reuptake inhibitors and tricyclic antidepressants, such as clomipramine, imipramine, or protriptyline, as well as other drugs that suppress REM sleep. Venlafaxine, an antidepressant which blocks the reuptake of serotonin and norepinephrine, has shown usefulness in managing symptoms of cataplexy, however, it has notable side-effects including sleep disruption. The antidepressant class is used mainly for the treatment of cataplexy, for people with narcolepsy without cataplexy these are usually not used. Children
Common behavioral treatments for childhood narcolepsy include improved sleep hygiene, scheduled naps, and physical exercise.Many medications are used in treating adults and may be used to treat children. These medications include central nervous system stimulants such as methylphenidate, modafinil, amphetamine, and dextroamphetamine. Other medications, such as sodium oxybate or atomoxetine may also be used to counteract sleepiness. Medications such as sodium oxybate, venlafaxine, fluoxetine, and clomipramine may be prescribed if the child presents with cataplexy. Epidemiology
Estimates of frequency range from 0.2 per 100,000 in Israel to 600 per 100,000 in Japan. These differences may be due to how the studies were conducted or the populations themselves.In the United States, narcolepsy is estimated to affect as many as 200,000 Americans, but fewer than 50,000 are diagnosed. The prevalence of narcolepsy is about 1 per 2,000 persons. Narcolepsy is often mistaken for depression, epilepsy, the side effects of medications, poor sleeping habits or recreational drug use, making misdiagnosis likely.