Efficacy of fluticasone on cough.

I agree with A.H. Morice and coworkers that the relatively short half-life of sildenafil (3–4 h) may be a drawback of this drug. Patients’ compliance may rarely be an issue. However, the fluctuations in sildenafil plasma concentrations are poorly tolerated by some patients. A drug with a much longer halflife, such as tadalafil (,18 h), might be advantageous, but caution is necessary. GHOFRANI et al. [2] have demonstrated substantial variability in the haemodynamic effects of several phosphodiesterase-5 inhibitors. For the time being, there is a strong body of evidence for the safety and efficacy of sildenafil in pulmonary arterial hypertension, but there is a lack of comparable data for other phosphodiesterase-5 inhibitors, such as tadalafil. M.M. Hoeper Dept of Respiratory Medicine, Hannover Medical School, Hannover, Germany.