The Purple Pill Viagra typically refers to a generic or alternative version of Viagra used to treat erectile dysfunction (ED) in men. This term might be used colloquially, as the actual Viagra tablet is usually blue, but the term "purple pill" may be used about a different or generic form of Sildenafil or another ED medication with a different color and appearance. Sildenafil is also used to treat pulmonary arterial hypertension (PAH), a condition where the blood pressure in the arteries of the lungs is abnormally high. By dilating blood vessels in the lungs, Sildenafil helps reduce the workload on the heart.