["To examine the effect of sildenafil in patients with Raynaud's phenomenon (RP) secondary to limited cutaneous systemic sclerosis (lcSSc).", "In this double-blind, placebo-controlled study, 57 patients with RP secondary to lcSSc were randomized to receive modified-release sildenafil 100 mg once daily for 3 days followed by modified-release sildenafil 200 mg once daily for 25 days or placebo. The primary assessment was the percentage change in the number of RP attacks per week in the per-protocol population. Secondary end points included Raynaud's Condition Score, duration of attacks, RP pain score, endothelial dysfunction assessed by a peripheral arterial tonometric (PAT) device, and serum biomarker levels.", "The mean percentage reduction from baseline to day 28 in attacks per week was greater for modified-release sildenafil than for placebo (-44.0% versus -18.1%, P = 0.034); the mean number of attacks per week improved from 25.0 at baseline to 19.3 after placebo treatment and from 30.5 to 18.7 after modified-release sildenafil treatment (P = 0.244). Decreases from baseline in Raynaud's Condition Score, duration of attacks, and RP pain score were not significantly different between groups. Mean values and changes from baseline in PAT responses and serum biomarker levels were similar between groups. The most frequent adverse events were headache and dyspepsia; the majority of adverse events were mild or moderate."] Does modified-release sildenafil reduce Raynaud 's phenomenon attack frequency in limited cutaneous systemic sclerosis?