Treatment with short acting β2 agonists for exacerbations of COPD results in clinical improvement. It has not been established whether combining short acting β2 agonists to other bronchodilators is more effective than β2 agonists alone. The aim of this study is to evaluate the efficacy and safety of combination of SABA and MgSO4 in comparison to SABA and ipratropium bromide (IB) in patients attending the emergency department for AECOPD.

Patients presenting to the emergency department with exacerbation of COPD are randomized to receive nebulised ipratropuim bromide or combined nebulised and an intravenous bolus of magnesium sulfate during 1 hour.

Inclusion Criteria:

• 40 years old or over
• have known or suspected COPD based on pulmonary function test, arterial blood gas, clinical history, physical examination, and chest radiograph
• worsening of dyspnea within 2 weeks,
• partial pressure of arterial carbon dioxide (PaCO2) >45 mmHg
• respiratory rate >24/min
• arterial pH <7.35
• partial pressure of arterial oxygen (PaO2) <50 mmHg under room air

Exclusion Criteria:

• hypersensitivity to anticholinergics and to magnesium sulfate
• patients that received anticholinergics within 6 hours before ED admission
• systolic arterial pressure <90 mmHg or need to vasoactive drugs