Clinical Question: Is sildenafil (Viagra) more effective than bosentan (Tracleer) in the treatment of patients with class III pulmonary hypertension?

Setting: Outpatient (specialty)

Study Design: Randomized controlled trial (double-blinded)

Allocation: Concealed

Synopsis: Investigators recruited consecutive patients with World Health Organization class III pulmonary hypertension. These patients could walk only 150 to 450 meters in six minutes. Patients with threefold elevations of liver enzymes, previous treatment with sildenafil or bosentan, and those in need of urgent therapy were excluded. Eligible patients were randomized (allocated via central computer) to receive sildenafil (n = 14) or bosentan (n = 12). The patients received bosentan in a dosage of 62.5 mg twice daily or sildenafil in a dosage of 50 mg twice daily for the first four weeks. Patients were then titrated up to 50 mg of sildenafil three times daily or 125 mg of bosentan twice daily (with a midday placebo tablet) for the next 12 weeks.

The researchers evaluated a variety of intermediate outcomes (e.g., right ventricular mass, change in six-minute walk distance, cardiac function) and symptom scores via intention to treat. One patient treated with sildenafil died and another did not finish the study. The researchers assigned worst-case values for missing data. Although each treatment increased patients’ exercise capacity and quality of life, there were no differences between the treatments on any of the outcomes. The study was designed to detect tiny differences in right ventricle mass.

Bottom Line: In this small study, sildenafil and bosentan had similar effects on patients with moderately severe pulmonary hypertension. (Level of Evidence: 1b)