Abstract Introduction Solriamfetol is a dopamine and norepinephrine reuptake inhibitor indicated to improve wakefulness in adult patients with excessive daytime sleepiness associated with obstructive sleep apnea (OSA; 37.5-150 mg/d) or narcolepsy (75-150 mg/d). Previous studies reported small mean increases in blood pressure (BP); however, the time course of these effects has not been evaluated. In addition, effects on BP dipping, which has been shown to be a risk factor for adverse cardiovascular outcomes have not been evaluated. These analyses evaluated the effects of solriamfetol treatment on BP using 24-hour ambulatory blood pressure monitoring (ABPM) and on the percentage of OSA patients with a non-dipping BP profile. Methods Twenty-four-hour ABPM was conducted at baseline and week 8 in a 12-week randomized controlled trial in participants with OSA (n=474). Results At week 8, increases in BP were apparent in the 75 and 300 mg dose groups from ~6 AM until 8 PM. At baseline, 58% (placebo) and 55% (combined solriamfetol) of participants were non-dippers (defined as <10% decrease in mean arterial pressure [MAP] during sleep). There was no increase in the percentage of non-dippers at week 8 relative to baseline (placebo, 56%; combined solriamfetol, 53%). Results were similar when dipping was defined by changes in systolic BP and diastolic BP. Conclusion The effects of solriamfetol on BP at the highest approved dose of 150 mg/d are transient across the day. Solriamfetol was not observed to have an increase in non-dipping classification in participants with OSA at any dose studied. Support Jazz Pharmaceuticals