Melatonin improves sleep and reduces nitrite in the exhaled breath condensate in cystic fibrosis--a randomized, double-blind placebo-controlled study.

Cystic fibrosis (CF) is a chronic progressive disorder characterized by repeated episodes of respiratory infection. Impaired sleep is common in CF leading to reduced quality of life. Melatonin, a secretory product of the pineal gland, has an important function in the synchronization of circadian rhythms, including the sleep-wake cycle, and has been shown to possess significant anti-oxidant properties.