Is it safe for a patient with chronic obstructive pulmonary disease (COPD) to be on high doses (e.g., 100 mg b.i.d.) of metoprolol (Toprol XL)? — Carmen Booth, ARNP-BC, Hahira, Ga.

Patients with COPD often die of cardiovascular causes, as impaired lung function has been shown to be an independent risk factor for coronary events and cardiac arrhythmias. Beta blockers have been proven effective in the management of patients with cardiovascular disease yet have been underused in patients with COPD due to a concern for acute bronchospasm.

Evidence from various clinical trials and meta-analyses indicates that such cardioselective beta blockers as metoprolol have benefits that outweigh the risks and should not be withheld from patients with COPD.

Although the recommendation is to start patients at a low dose of a beta blocker and titrate up as needed while assessing lung function, there are studies that show doses of 200 mg of metoprolol had no clinically significant effect on respiratory function (Respir Med. 2003;97:1094-1101). — Eileen F. Campbell, MSN, CRNP (156-7)