Tafenoquine Succinate

Absorption

Oral bioavailability of solriamfetol is approximately 95%. Peak plasma concentration is reached in 2 hours (with a range of 1.25 to 3 hours) in fasted patients. When solriamfetol is taken with a high fat meal, the time to peak plasma concentration increases to 3 hours.

Toxicity

Age, gender, and race do not significantly affect solriamfetol pharmacokinetics and no dose adjustments were made in clinical trials for patients over 65 years.
Patients with renal failure experience increases in half life between 1.2 and 3.9 times that in healthy patients. 21% of solriamfetol was removed by hemodialysis, however time to peak concentration was not affected.
Solriamfetol is not expected to lead to adverse effects in pregnancy. Maternal and fetal toxicity was seen in animal studies at ≥4 and 5 times the maximum recommended human dose and teratogenicity was seen at 19 and ≥5 times the maximum recommended human dose.
Breastfed infants should be monitored for adverse reactions such as agitation, insomnia, anorexia, and reduced weight gain as solriamfetol is present in breast milk. However, there is no currently available data on the effect of solriamfetol in breast milk on breast fed inants.
Safety and effectiveness of solriamfetol in pediatric patients has not been established in clinical studies.
Solriamfetol does not display different safety or effectiveness in geriatric populations.
Dosage adjustments are recommended for patients with eGFR <60mL/min/1.73m^2 and solriamfetol is not recommended for patients with an eGFR <15mL/min/1.73m^2.

The Uses of Tafenoquine Succinate

Solriamfetol is a selective dopamine and norepinephrine reuptake inhibitor used in the treatment of sleep apnea and narcolepsy.

Indications

Solriamfetol is indicated for treatment of daytime sleepiness associated with obstructive sleep apnea and narcolepsy, but is not a treatment for the underlying airway obstruction in apnea patients.

Background

Solriamfetol marketed under the brand name Sunosi by Jazz Pharmaceuticals in the United States is a dopamine and norepinephrine reuptake inhibitor (DNRI) indicated in treating daytime sleepiness associated with narcolepsy or obstructive sleep apnea. Solriamfetol was given FDA approval in 2019.

Pharmacokinetics

Solriamfetol weakly binds to dopamine and norepinephrine transporters but not serotonin transporters. Solriamfetol does not bind to dopamine, serotonin, norepinephrine, GABA, adenosine, histamine, orexin, benzodiazepines, or muscarinic and nicotinic receptors.
Solriamfetol is also associated with a mean increase of 21 beats per minute (BPM) in heart rate in patients taking 300mg (twice the maximum recommended dose) and 27 BPM in patients taking 900mg (six times the maximum recommended dose). 300mg of solriamfetol does not increase the QTcF interval to a clinically relevant degree.

Metabolism

Solriamfetol does not undergo significant metabolism in humans, though less than 1% of solriamfetol is metabolized to N-acetyl solriamfetol.