This study assessed clinical and angiographic efficacies of oral treatment with prednisone at low-dose (LD) versus the previous high-dose (HD) immunosuppressive dosage used after percutaneous coronary interventions (PCIs) with bare metal stents in patients with multivessel coronary artery disease. Forty-three patients with multivessel disease successfully treated with multiple PCIs were matched to the previous HD IMPRESS-2/MVD study population. The 43 patients were treated for 103 coronary stenoses and received 30-day oral prednisone treatment (LD group 1 mg/kg for 5 days, 0.5 mg/kg for 10 days, 0.25 mg/kg for 15 days) and were compared retrospectively with the 43 patients in the HD IMPRESS-2/MVD study with 116 treated coronary lesions (HD group 1 mg/kg for 10 days, 0.5 mg/kg for 20 days, 0.25 mg/kg for 15 days). The primary clinical end point was 12-month event-free survival rate (defined as freedom from death, myocardial infarction, and need for target vessel revascularization). The secondary end point was angiographic restenosis at 8 months assessed by quantitative coronary angiography. Event-free survival rates were 74% and 93% in the LD and HD groups, respectively (relative risk 4.6, 95% confidence interval 1.18 to 17.8, p = 0.019). Restenosis was observed in 4 lesions (4%) in the HD group and in 20 lesions (22%) in the LD group (p <0.001). Mean late lumen loss was 0.61 +/- 0.35 mm, and the loss index was 31.3 +/- 21.6% in the HD group compared with 0.87 +/- 0.61 mm and 52.03 +/- 25.1% in the LD group (p = 0.03 and 0.02, respectively). In conclusion, antirestenotic efficacy of oral treatment with prednisone after conventional PCI is dose sensitive. A 50% dose decrease in oral prednisone, as tested in this study, is less effective than the previously tested HD IMPRESS therapeutic scheme.