Vardenafil is commonly marketed as Levitra whereas Sildenafil is what is known as Viagra to many. Both these drugs are recommended for treating erectile dysfunction which is a condition in which a man is unable to achieve or maintain an erection. The two drugs treat the condition only if it is caused by physiological problems like reduced blood flow to the penile tissue rather than psychological causes such as stress. Structurally, Vardenafil and Sildenafil are very similar and they differ only in biochemical potential with that of the former being higher.
Both Vardenafil and Sildenafil belong to a group of drugs known as the phosphodiesterase type 5 inhibitors whose mechanism of action is by blocking the degradative action of the enzyme they inhibit. They stop the enzyme from breaking down a chemical messenger found in smooth muscles of penile tissue known as cyclic guanosine monophosphate. This chemical messenger is responsible for prolonging vasodilatation caused by the release of nitric oxide by nerve endings in the organ. It is this vasodilation that allows more blood to get to the penile tissue increasing the amounts of blood flowing to the area resulting in an erection.
Though the end results are the same, Vardenafil achieves the results at a much lower dose thanks to its being 10 times more potent than Sildenafil. What 2.5mg of Vardenafil can achieve requires 25mg of Sildenafil to do the same. Vardenafil is more selective compared to Sildenafil; that is, the former is more capable of attaching the specific enzyme than the latter. This means that the ability of vardenafil to induce harmful side effects is reduced greatly as the dose needed is much lower. It also does not inhibit phosphodiesterase-6 which Sildenafil does causing alterations in color perception. Both however still pose side effects to those who take them but have no serious implications. The most common side effects associated with Vardenafil are facial flushing and headache whereas those associated with Sildenafil include facial flushing, indigestion and headaches. Though not a clinically significant fact, Vernadafil acts longer than Sildenafil with its effects being felt for longer. Their action however is felt after about an hour of taking them and so each of them should be taken an hour or at least 30minutes before sexual encounters for best results.
When using Vardenafil, one should keep off a high-fat meal as it reduces its effectiveness. It is most effective when taken on an empty stomach and shows less tolerance to fatty meals compared to Sildenafil. Both are excreted via the fecal route as part of digestive system waste. Another similarity is that both should not be used in people with low blood pressure as they reduce the pressure even further.