Briefing Note: sildenafil (Revatio)

SMC accepted sildenafil for the treatment of pulmonary arterial hypertension (PAH). Its use should be restricted to initiation by specialists working in the Scottish Pulmonary Vascular Unit or others with appropriate expertise.

• Pulmonary arterial hypertension (PAH) is a rare and debilitating disease where there is severe narrowing of the blood vessels of the lungs causing abnormally high pressure in the vessels taking blood from the heart to the lungs. The disease varies in severity (or ‘class’).
• Sildenafil is a drug used to treat patients with PAH to improve their ability to carry out physical activity. It works by blocking the breakdown of a substance called cyclic guanosine monophosphate, allowing blood vessels to expand, thereby helping to lower the blood pressure and improve symptoms. It is given as a tablet and used in patients with slight (class II) or marked (class III) limitation of physical activity.
• There is limited evidence of effectiveness from short-term clinical trials. Patients who received sildenafil were able to walk slightly further in 6 minutes compared with the distance they could walk before receiving treatment. There was no increase in the distance walked by patients who received placebo (a dummy drug containing no active treatment).
• More patients who were given sildenafil in a study experienced flushing than patients who were given placebo.
• SMC accepted sildenafil for use in NHSScotland because it can be given as a tablet and is cheaper than another drug licensed for treatment of PAH.