Effect of subcutaneous lidocaine-hydroxypropyl-β-cyclodextrin (HP-β-CD) on quality of life in patients with post-COVID condition: a 36-week observational interrupted time series study.

Background: Post-COVID involves persistent, multisystem symptoms which are associated with inflammation, immune dysregulation, and autonomic dysfunction. The effects of currently applied treatments for post-COVID are limited. This study assessed the effectiveness of subcutaneous lidocaine-hydroxypropyl-β-cyclodextrin (HP-β-CD) for the treatment of post-COVID. Methods: This interrupted time series study was conducted at a Dutch outpatient clinic between August 2024 and April 2025. Adults with physician-diagnosed post-COVID (n = 103) underwent a 4-week pre-treatment observation followed by 24-36 weeks of home-based subcutaneous lidocaine 5% with HP-β-CD, administered using a 3-phase protocol: 500 mg every other day (weeks 1-7), 500 mg daily (weeks 7-14), and up to 1000 mg/day (after week 14, in non-responders). The primary outcome was health-related quality of life (Short Form-12 (SF-12), physical and mental component summary scores). Secondary outcomes included symptom burden (daily app-based questionnaire) and adverse events. Findings: Among 103 participants (mean [SD] age 48·1 [13·0] years; 67% women; median [IQR] symptom duration 31·5 [24·3-43·3] months), 76% completed 24 weeks and 71% completed 36 weeks of treatment. At week 24, the physical and mental component scores increased by 2·20 and 5·16 points, respectively; at week 36, by 4·13 and 7·00 points (all p < 0·0001). Twenty-seven of 30 symptoms improved significantly at week 24 of treatment compared to pre-treatment. Mild adverse events occurred in 89% of participants, mostly injection-site reactions; no serious adverse events were reported. Interpretation: Subcutaneous lidocaine-HP-β-CD was associated with significantly improved quality of life and symptom burden in patients with post-COVID. This home-administered intervention offers a scalable and potentially disease-modifying approach for a disabling condition with no approved treatment to date. Funding: Excellent Care Clinics funded the treatment provided in this study.