However, in case of severe diseases, such as varied arrhythmias, heart failure, coronary heart disease, extreme hypertension or a tendency to hypotension, it is best to refuse to take Viagra and to deal with related diseases as an alternative of impotence. Levitra very slightly outperformed Viagra in one study of men with erectile dysfunction and danger components for cardiovascular illness, with more males preferring Levitra over Viagra (39% to 35%). Neither drug brought about important unwanted effects. It acts as a PDE-5 inhibitor, counteracting components contributing to erectile dysfunction. Levitra improved erectile perform in males with renal transplants, a demographic that continuously suffers from erectile dysfunction. In a study of 979 men who had been taking Viagra, over 94% of individuals reported improved erectile operate over the course of four years of using the drug. Mild unwanted effects, resembling flushing and headaches, have been reported, however, and were more common on larger doses of the drug. However, a uncommon side effect, vision loss, has been reported with folks who have used PDE5 inhibitors, together with Viagra, Levitra, and Cialis. A 2011 comparability of research of Cialis, Levitra, and Viagra concluded that there was "insufficient data" to resolve which drug was best at treating erectile dysfunction.
