Solriamfetol
This page is a reference summary of published evidence and regulatory documents. It is not a substitute for individual medical advice, and it is not a recommendation to take or avoid any medicine.
Medically reviewed by Dr. Sofia Lindqvist, · Last reviewed 11 August 2026
Solriamfetol, sold as Sunosi, is a dopamine and norepinephrine reuptake inhibitor approved by the FDA in 2019. It was developed for a specific unmet need: patients who remain sleepy despite treatment with the existing wakefulness agents.
On this page
How it works
75 mg
usual starting dose, narcolepsy
150 mg
maximum daily dose
~7 h
elimination half-life
Renal
route of clearance
Solriamfetol is a dopamine and norepinephrine reuptake inhibitor, or DNRI. The closest widely known drug by mechanism is bupropion; the main difference is that bupropion also acts on nicotinic receptors and solriamfetol does not.
Its precise mechanism for improving wakefulness is not fully established. Efficacy is thought to be mediated through the reuptake inhibition itself. That makes it mechanistically distinct from modafinil, a much weaker dopamine reuptake inhibitor with substantial downstream effects on the orexin and histamine systems.
Approved uses
The same three indications as modafinil: narcolepsy, excessive sleepiness associated with obstructive sleep apnea on adequate primary treatment, and shift work disorder.
| Indication | Population | Starting dose |
|---|---|---|
| Narcolepsy | Excessive daytime sleepiness in adults | 75 mg once daily |
| Obstructive sleep apnea | Excessive daytime sleepiness in adults on primary therapy | 37.5 mg once daily |
Solriamfetol has no effect on cataplexy. For narcolepsy type 1, cataplexy control needs a different or additional drug — see pitolisant or sodium oxybate.
Dosing and pharmacokinetics
Based on efficacy and tolerability, the dose may be doubled at intervals of at least three days, to a maximum of 150 mg daily. In practice, physicians commonly start at 75 mg per day for narcolepsy and adjust once.
Time to peak concentration is about two hours. The elimination half-life is roughly seven hours — considerably shorter than modafinil’s fifteen. A high-fat meal delays the peak by about an hour with minimal change to overall exposure.
The chain from transporter binding to wakefulness. The downstream hypothalamic effects are as important to the clinical picture as the dopamine step.
Kidneys, not liver
Solriamfetol is minimally metabolised and excreted renally as unchanged drug. This distinguishes it sharply from modafinil, which is cleared hepatically. The practical consequence is that dose adjustment is driven by kidney function rather than liver function — the reverse of modafinil. That can make it a preferable option in hepatic impairment and a more cautious one in renal impairment.
Evidence
Approval rested on a phase 3 trial in which 239 patients with narcolepsy were randomised to 75 mg, 150 mg, 300 mg or placebo once daily. Patients on 150 mg showed statistically significant improvement on the maintenance of wakefulness test and the Epworth Sleepiness Scale at week 12, with effects visible from week 1.
37.5 mg
4.5 min
75 mg
8.9 min
150 mg
10.7 min
Treatment-effect difference versus placebo on the maintenance of wakefulness test, in minutes of sustained wakefulness, by dose.
At week 12, 78.2 percent of patients on 150 mg reported improvement on the patient global impression of change scale, against 39.7 percent on placebo.
Where it fits
Solriamfetol is generally a second-line option, considered when modafinil or armodafinil have proved inadequate or poorly tolerated. Clinicians describe response as difficult to predict in advance: some patients do well on the agent that would not have been the obvious first choice.
Does solriamfetol treat cataplexy?
No. It improves daytime sleepiness only. Patients with narcolepsy type 1 who need cataplexy control require a different or additional treatment, such as pitolisant or sodium oxybate.
How is solriamfetol different from modafinil?
It is a straightforward dopamine and norepinephrine reuptake inhibitor, cleared by the kidneys, with a half-life near seven hours. Modafinil is a weak reuptake inhibitor with substantial downstream orexin and histamine effects, cleared by the liver, with a half-life near fifteen.
Is a higher dose better?
The label notes that doses above 150 mg per day do not add enough effectiveness to outweigh dose-related adverse reactions.