by Stephan L. Kamholz, MD
Dr. Kamholz is Chairman of the Department of Medicine for the North Bronx Healthcare Network (NBHN), Jacobi Medical Center & North Central Bronx Hospital; Professor and Vice Chairman of the Department of Medicine at Albert Einstein College of Medicine; and Assistant Dean for the NBHN for Research and Education.
As reported in the May/June Pulmonary Reviews, Rocker et al highlighted discrepancies between the positive experiences of advanced COPD patients and family caregivers with the use of opioids for refractory dyspnea, and the reluctance of Canadian physicians to prescribe such therapy. This gap in clinical care is difficult to explain, particularly in the context of extensive exploration of the safety and efficacy of the therapy.
More than 30 years ago, Woodcock et al reported that dihydrocodeine improved breathlessness and exercise tolerance in 12 normocapnic patients with moderate or severe dyspnea due to COPD. The investigators suggested that opiates may be valuable for the treatment of breathlessness.Shortly thereafter, Johnson, Woodcock, and Geddes reported that 15 mg oral dihydrocodeine taken 30 minutes before exercise “offers appreciable benefit to patients with severe breathlessness due to chronic airflow obstruction.”
In 1989, Light et al demonstrated that administration of an oral morphine solution (0.8 mg/kg) improved maximal exercise workload by 18% and oxygen uptake by 19.3% in 13 normocapnic COPD patients (FEV1, 0.99 ±0.48 L). These patients did not experience increased dyspnea (no ▲ Borg score) despite higher minute ventilation at maximal exercise, and the increase in exercise tolerance was attributed to a higher PaCO2 resulting in lowered ventilation requirements for a given workload, as well as a reduction in the perception of breathlessness.
Fast forward to the 2010 American College of Chest Physicians Consensus Statement on the Management of Dyspnea in Patients with Advanced Lung or Heart Disease—which concluded that “opioids should be dosed and titrated for relief of dyspnea in the individual patient.” Furthermore, in the guideline, 10 of 11 cited studies which provided information on arterial blood gases did not report any significant changes in oxygenation after opioid administration, and PaCO2 did not exceed 40 mm Hg. Similarly, 2011 clinical practice guidelines published by the Canadian Thoracic Society unequivocally support the role of opioids in the management of dyspnea in COPD patients.
What next? Intense efforts must be made by medical professional societies and health insurers to enhance physicians’ familiarity with the dyspnea treatment consensus guidelines and the evidence upon which the recommendations for opioid therapy are based. In this way, the gap in clinical care may be narrowed, and COPD patients may have fuller and more comfortable days.