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N-acetylcysteine significantly reduces exacerbation of chronic bronchitis, COPD

N-acetylcysteine significantly reduced exacerbation events among individuals with chronic bronchitis and COPD, according to results of a meta-analysis.

Patients with chronic bronchitis who have documented airway obstruction should receive N-acetylcysteine (NAC) at a dose of at least 1,200 mg per day to prevent exacerbation, whereas a 600-mg daily dose appeared sufficient for those with chronic bronchitis who did not have airway obstruction, researchers wrote.

“The results of this meta-analysis provide good evidence that NAC can be considered an important, safe and well-tolerated therapeutic agent to be integrated into the regular treatment regimens of patients with COPD, but also that NAC should be administered at high dose,” Mario Cazzola, MD, of the department of systems medicine at University of Rome Tor Vergata, and colleagues wrote. “Since the administration of NAC at low dose provides a more marked risk reduction for the overall set of studies (without regard to the diagnosis) than that for the subset of studies with a validated COPD diagnosis, this suggests that a low dose is sufficient in providing benefit to patients with chronic bronchitis, but not to patients with COPD.”

Cazzola and colleagues performed a meta-analysis of 13 studies that included 4,155 patients with COPD. Of this cohort, 1,933 patients received NAC and 2,222 patients received placebo or acted as controls.

Researchers defined low-dose NAC as 600 mg daily or less, and they defined high-dose NAC as more than 600 mg daily.

Nine studies included in the analysis used low-dose NAC, three used high-dose NAC and one study evaluated both low-dose and high-dose NAC.

Use of NAC appeared associated with fewer exacerbation events overall for patients with chronic bronchitis or COPD (RR = 0.75; 95% CI, 0.66-0.84). When NAC was administered in low doses for 1,298 patients in 10 studies, the relative risk for exacerbation significantly decreased for patients with COPD (RR = 0.76; 95% CI, 0.65-0.89). There also was a significant reduction in COPD exacerbation for 635 patients in four studies who received high doses of NAC (RR = 0.65; 95% CI, 0.49-0.88), Cazzola and colleagues wrote.

NAC appeared well tolerated in both low doses (RR = 0.93; 95% CI, 0.89-0.97) and high doses (RR = 1.11; 95% CI, 0.89-1.39), researchers wrote.

Disclosure: Cazzola reports personal fees from Zambon SpA outside the submitted work. Please see the full study for a list of all other researchers’ relevant financial disclosures.