Long-term effects of protriptyline in patients with chronic obstructive pulmonary disease

Protriptyline has been shown to improve nocturnal and diurnal hypoxemia in patients with chronic obstructive pulmonary disease in short trials. We prospectively evaluated the long-term effects of protriptyline on pulmonary functions (lung volume and expiratory flow, arterial blood gases) and sleep characteristics (sleep architecture, nocturnal desaturations) in these patients. Sixteen patients previously studied before and after 10 wk of protriptyline treatment were reevaluated after a long-term follow-up (range, 18 to 63 months); the results of those still receiving protriptyline were compared with those who stopped using the drug. Nine patients were still receiving protriptyline at the follow-up visit (10 to 20 mg/day at bedtime), and seven had stopped using the drug because of side effects. These two groups of patients did not differ in their follow-up duration, age, weight, pulmonary functions, and sleep architecture, or in their protriptyline-induced changes in diurnal arterial blood gases and nocturnal desaturation. At the follow-up visit, arterial blood gas determinations had returned to baseline values in all patients no longer receiving protriptyline. In the other group there was no difference between the baseline and follow-up PaO2 values (57.4 +/- 3.4 and 57.0 +/- 1.2 mm Hg, mean +/- SEM). There was no difference in the results of arterial blood gas determinations and pulmonary function tests obtained at the different visits between the two groups. Sleep architecture differed between these two groups, REM sleep time being shorter and the slow-wave sleep time being longer in the patients still receiving the drug. In both groups the cumulative SaO2 curves were similar to those obtained at baseline.(ABSTRACT TRUNCATED AT 250 WORDS)