Volumetric dilution nasal spray as a harm reduction strategy for intranasal psychoactive substance use: a practical framework and rationale

Intranasal insufflation of cocaine, MDMA, and ketamine is associated with a well-documented spectrum of nasal complications driven by mechanical trauma, vasoconstriction-induced mucosal ischaemia, and chemical irritation from adulterants. Volumetric dilution nasal spray (VDNS) — dissolving the substance in sterile saline and delivering it via a calibrated spray device — eliminates powder particle trauma, delivers the substance in a mucosal-compatible vehicle, and converts uncontrolled line-based dosing into a quantifiable per-spray unit. This article describes the pharmacological rationale, pathophysiological mechanisms targeted, practical implementation framework, and limitations of this approach for cocaine, MDMA, and ketamine. Formal evaluation of acceptability and nasal morbidity impact is needed; pending such data, dissemination in community harm reduction settings is supported by biological plausibility and field practice.