Sildenafil improves six-minute walk distance in chronic obstructive pulmonary disease: a randomised, double-blind, placebo-controlled trial.

BACKGROUND: Sildenafil has been found to improve exercise capacity and haemodynamic parameters in patients with various pulmonary disorders. This study was undertaken to evaluate its efficacy in severe chronic obstructive pulmonary disease (COPD). METHODS: In this double-blind, randomised, placebo-controlled study, 37 patients with severe COPD received either sildenafil or placebo for 12 weeks. Distance covered in six-minute walk test (6MWD) was taken as primary end-point. Pulmonary artery pressure (PAP) was measured as secondary end point. RESULTS: Thirty-three patients (15 in sildenafil arm and 18 in placebo arm) completed the study. Non-parametric tests were used for comparison. There was significant increase in 6MWD from baseline after three months of follow-up in sildenafil users (median change in distance covered in six-minute walk test (delta6MWD) = 190m) as compared to placebo users (delta6MWD = 0m, p < 0.05). The PAP decreased significantly (chi2 = 14.94, p < 0.05) in sildenafil group after three months, while it did not change significantly among placebo group (chi2 = 3.84, p > 0.05). CONCLUSION: Sildenafil improved 6MWD and PAP in patients with severe COPD.

Adjunctive magnesium infusion therapy in acute myocardial infarction.

Intravenous magnesium therapy in acute myocardial infarction (MI) has been shown to be beneficial in many studies. However, these effects are not consistent from one trial to another, and their clinical significance is often questionable. A total of 78 consecutive patients were included in a prospective placebo controlled, randomized study of the effects of intravenous magnesium sulfate infusion in acute MI. Of these, 52 (66%) received intravenous streptokinase and the rest belonged to a non-thrombolysed group. These patients were randomized to receive magnesium sulfate infusion (8 mmol over 5 min followed by 65 mmol over 24 h) or placebo. The end points were serious arrhythmias, left ventricular ejection fraction (LVEF) and death during hospital stay and at the end of 28 days. LVEF measured by radionuclide ventriculography at discharge (9 +/- 5 days) was similar in two groups (41 +/- 11 vs. 39 +/- 10; magnesium vs. placebo respectively, P = 0.40). However, the LVEF of the placebo-treated thrombolysed group was higher than the non-thrombolysed group (42 +/- 10 vs. 37 +/- 0, P = 0.02). Incidence of nonsustained ventricular tachycardia (NSVT) was higher with placebo than with magnesium (50% vs. 23% respectively, P < 0.02, odds ratio = 0.29; 95% confidence intervals (CI) 0.1-0.85). Mortality during hospital stay and at the end of 28 days was also similar in both the groups. Thus, the administration of magnesium infusion as an adjunct to thrombolytic therapy remains to be of questionable benefit.