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 multicenter, open clinical trial lasting 11 weeks and conducted in winter. Primary outcome measures were frequency and severity of RP attacks, and number of digital ulcers. Secondary outcome measure was improvement in digital cold challenge test assessed by photoelectric plethysmography. Patients received a continuous 5 day intravenous infusion of NAC starting with a 2 h loading 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 posttreatment followup. Both frequency and severity of RP attacks decreased significantly compared to pretreatment values. Active ulcers were significantly less numerous at all followup visits (25.18% of baseline count on Day 33 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 controlled, and reversible.

CONCLUSION

N-acetylcysteine appears to be safe for the treatment of RP secondary to SSc. These preliminary data warrant further controlled studies.