N-Acetyl Cysteine Slows Lung Decline in Pulmonary Fibrosis

The Idiopathic Pulmonary Fibrosis International Group Exploring N-Acetyl Cysteine I Annual (IFIGENIA) trial reported that N-acetyl cysteine, a precursor of the antioxidant glutathione, slows the deterioration of lung function in patients being treated for idiopathic pulmonary fibrosis. Idiopathic pulmonary fibrosis is a chronic progressive interstitial pneumonia whose cause is unknown, although an oxidant-antioxidant imbalance may contribute to the disease process. The findings were reported in the November 24 2005 issue of the New England Journal of Medicine.

In a double-blind placebo controlled trial, 182 pulmonary fibrosis patients were randomized to receive 600 milligrams N-acetylcysteine or a placebo three times per day for one year. Participants were also given prednisone and azathioprine, which are standard drugs prescribed for the disease. Vital capacity and and single-breath carbon monoxide diffusing capacity, which are measures of lung function, were measured at the beginning of the study, and at six and twelve months.

One hundred eight of the original participants completed the one-year study. Subjects who received N-acetyl cysteine experienced a slower loss of vital capacity and single-breath carbon monoxide diffusing capacity than did those who received the placebo, and had greater values for both measurements at twelve months. Mortality was slightly lower among those who received N-acetyl cysteine.

The authors concluded that adding 600 milligrams acetyl cysteine three times daily to a regimen of prednisone and azathioprine helps preserve lung function in idiopathic pulmonary fibrosis patients better than drug therapy alone. "High-dose acetylcysteine in addition to standard therapy is," they write, "therefore, a rational treatment option for patients with idiopathic pulmonary fibrosis."

Reference

Hunninghake, GW. Antioxidant Therapy for Idiopathic Pulmonary Fibrosis. New Eng J Med Nov 24, 2005; 353:2285-2287.

Key concepts: Antioxidant, N-acetyl cysteine, NAC, pulmonary fibrosis