Intravenous N-acetylcysteine for treatment of Raynaud's phenomenon secondary to systemic sclerosis: A pilot study

Objective. To assess the efficacy and tolerability of N-acetylcysteine (NAC in patients with Raynaud's phenomenon (RP) secondary to Systemic sclerosis (scleroderma; SSc). Methods. Twenty-two patients with RP secondary to SSc were enrolled in a mu lticenter, open clinical trial lasting I I weeks and conducted in winter. P rimary outcome measures were frequency and severity of RP attacks, and numb er of digital ulcers. Secondary outcome measure was improvement in digital cold challenge test assessed by photoelectric plethysmography. Patients rec eived a continuous 5 day intravenous infusion of NAC starting with a 2 h lo ading dose of 150 mg/kg subsequently adjusted to 15 mg/kg/h. Results. All 22 patients completed the 5 day infusion and 20 of them the Po sttreatment followup. Both frequency and severity of RP attacks decreased s ignificantly compared to pretreatment values. Active ulcers were significan tly less numerous at all followup visits (25.18% of baseline count on Day 3 3 from the beginning of infusion). In the cold challenge test mean recovery time fell by 69.56%, 67.70%, 71.42%, and 71.05% on Days 12, 19, 33, and 61 from the beginning of treatment. Side effects were minor, easily controlle d, and reversible. Conclusion. N-acetylcysteine appears to be safe for the treatment of RP sec ondary to SSc. These preliminary data warrant further controlled studies.