Sodium oxybate has been FDA approved for narcolepsy since 2002 as an immediate-release formulation requiring twice-nightly dosing, with a middle-of-the-night dose taken 2.5–4 h after the first dose per the product label.

Postmarketing reports show that patients may accidentally take their second dose less than 2.5 h after the first dose, which has been associated with moderate to severe adverse events, sometimes requiring hospitalization or medical treatment in an emergency department.

This risk is not currently described in immediate-release oxybate product labeling; patients, caregivers, clinicians, and Poison Control Centers should be aware of the risk of accidentally taking the second dose of twice-nightly immediate-release oxybates earlier than 2.5 h after the first dose and the harm that may occur in association with early dosing.