[Value of orally administered retard morphine for therapy of severe pulmonary emphysema of the pink-puffer type. A pilot study].

BACKGROUND AND OBJECTIVE

In severe "pink puffer" emphysema the patients' physical capacity is limited by dyspnoea despite maximal application of established treatment. This pilot study investigated the effect of retarded morphine, taken orally for 10 days, on ventilation, dyspnoea, walking capacity and wakefulness.

PATIENTS AND METHODS

Twenty clinically stable patients (11 men, 9 women, mean age 68.5 [50-81] years) with "pink puffer" emphysema were studied over a period of 10 days in a prospective, non-controlled trial of cross-over design. Criteria for inclusion in the study were: 1-second forced expiratory volume (FEV1) < 1 I, vital capacity < 50% and normocapnia. In addition to their existing therapy patients received either no further therapy or retarded morphine. Morphine dosage was increased to maximally 3 x 30 mg daily, depending on effectiveness and side effects, dyspnoea at rest and immediately after a 6-min walk (assessed with Borg's visual analog scale), maximal walking capacity were determined, as well as blood gases, respiratory minute volume and the respiratory drive (airway occlusion pressure [P0.1]), responsiveness of the respiratory pathways to CO2 and wakefulness (concentration, fatigue, interest in surroundings).

RESULTS

Twelve patients completed the study (group A). In the remaining patients (group B) the test had to be stopped prematurely because of undesirable side effects or an exacerbation of the underlying infection. In group A, morphine (mean dosage: 49.2 +/- 28.4 mg/d) caused a reduction of PaO2, dyspnoea on activity, the resting minute respiratory volume, respiratory drive and CO2 response, and an increase in PaCO2, HCO3- and the 6-min walking distance. Morphine did not produce a change in subjectively evaluated vigilance and the blood pH.

CONCLUSION

After strict patient selection oral morphine produced a reduction of exercise dyspnoea and an increase in walking capacity in half of the patients with severe pulmonary emphysema. There also occurred a slight rise in PaCO2 without any relevant respiratory acidosis or significant decrease in wakefulness.