The bottom-up pathway emerges from the ascending reticular arousal system (ARAS) and activates the cortex via well-characterized thalamic and nonthalamic pathways through cholinergic and aminergic neurotransmission. The bottom-up pathway represents the leverage point for pharmaceutical interventions. It is complemented by a corticothalamic top-down pathway, which appears to be modifiable through noninvasive brain stimulation (NIBS) techniques. A single case report study indicates that high-frequency repetitive transcranial magnetic stimulation (HF rTMS) over the left dorsolateral prefrontal cortex (DLPFC) might represent an alternative choice for symptom control in narcoleptic patients with cataplexy. rTMS may also exert intrinsic effects on hypersomnia in depressed adolescents. Mazindol
Mazindol is a stimulant similar to amphetamines that "has been shown to be effective in treating hypersomnia in narcoleptics." However, it is not currently approved in the US. Selegiline
Selegiline, monoamine oxidase type B (MAO-B) inhibitor works by slowing the breakdown of certain substances in the brain (mostly dopamine, but also serotonin and norepinephrine). It may also be useful, as it is also a metabolic precursor of amphetamine and exerts most of its therapeutic effects through amphetamine metabolism. It is not commonly prescribed for people with narcolepsy because of the high dosage required and potential for severe side effects. Atomoxetine
Atomoxetine (or reboxetine in Europe) is an adrenergic reuptake inhibitor which increases wakefulness (generally less strongly than the medications which act on dopamine) and which has been argued to have a "clear use in the therapeutic arsenal against narcolepsy and hypersomnia although undocumented by clinical trials."
One small study, which used a dose of 2 mg slow-release melatonin at bedtime, found that 50% of participants had “shortened nocturnal sleep duration, decreased sleep drunkenness and relieved daytime sleepiness.” Other studies have shown that melatonin synchronizes the circadian rhythms, and improves the “onset, duration and quality of sleep.”

Levothyroxine
There have been some studies suggesting levothyroxine as a possible treatment for IH, especially for patients with subclinical hypothyroidism. This treatment does carry potential risks (especially for patients without hypothyroidism or subclinical hypothroidism), which include cardiac arrhythmia. Hypocretin agonists
Hypocretin-1 has been shown to be strongly wake-promoting in animal models, but it does not cross the blood-brain barrier. Suvorexant, a hypocretin receptor antagonist, has been developed to limit the natural effects of hypocretin in patients with insomnia. It is therefore possible that a hypocretin agonist may be similarly developed for the treatment of hypersomnia. Acetylcholinesterase inhibitor
Antidepressants seems to have some therapeutic effects as they enhance synaptic levels of noradrenaline and serotonin and for same reason enhancing the levels of acetylcholine may have some therapeutic effect. Donepezil showed improvement in one patient by decreasing ESS score from 20 up to 14. Memantine has also shown some positive effect on a patient with narcolepsy. Levodopa
Levodopa is an amino acid and is the precursor to the neurotransmitters dopamine, norepinephrine (noradrenaline), and epinephrine (adrenaline).