Effects of High- Versus Low-Sodium Oxybate on Blood Pressure in Patients With Narcolepsy

BACKGROUND: People with narcolepsy are at increased risk for hypertension and cardiovascular disease; excessive sodium intake is linked to both. METHODS: We studied patients with narcolepsy and office systolic blood pressures (BPs) of 130 to 155 mm Hg taking twice-nightly high-sodium oxybate for ≥6 weeks who switched to low-sodium oxybate at the same dosage. The primary end point was the change from baseline in mean 24-hour ambulatory systolic BP at the end of treatment (≈6 weeks after switching). Secondary and exploratory end points included changes in diastolic BP, office BP, and 24-hour sodium excretion. RESULTS: Patients (n=43) had a mean age of 45 years, were 65% female, 33% on antihypertensives, with baseline mean (SD) office BP of 138.0/85.2 (5.7/6.6). Mean (SD) total high- and low-sodium oxybate dosages of 8.0 (1.1) and 8.1 (1.1) g/night, respectively, represented 1456.5 (206.2) and 117.8 (16.3) mg of sodium. The median 24-hour urinary sodium was 4278 mg/d at baseline and 2703 mg/d at the end of treatment (median change, 1288 mg/d). Mean (SE) 24-hour ambulatory systolic BPs at baseline and study end were 132.3 (1.8) and 128.2 (1.8) mm Hg (least-squares mean change, −4.1 [95% CI, −6.9 to −1.4] mm Hg; 1-sided P =0.0019). BP changes by narcolepsy subtype, sex, body mass index, baseline office BP, and baseline antihypertensive use were consistent with the overall effect size. CONCLUSIONS: People with narcolepsy switching from high- to low-sodium oxybate showed substantially reduced daily medication-related sodium intake and significant 24-hour BP reductions. These results demonstrate the importance of reducing pharmaceutical sodium content in this elevated cardiovascular risk patient population. REGISTRATION: URL: https://www.clinicaltrials.gov ; Unique identifier: NCT05869773.