Tell your doctor if you have fructose intolerance. Since vardenafil is used as needed, you are not likely to be on a dosing schedule. Use the medicine exactly as directed. If you are using the disintegrating tablet, make sure your hands are dry before you handle the tablet. Tell your doctor if any of these symptoms are severe or do not go away: headache. · The penis is one of the areas where this enzyme works. Erectile dysfunction is a condition where the penis does not harden and expand when a man is sexually excited, or when he cannot keep an erection. When a man is sexually stimulated, his body’s normal response is to increase blood flow to his penis to produce an erection. What side effects can this medication cause? erection that lasts longer than 4 hours. sudden severe loss of vision (see below for more information) blurred vision. changes in color vision (seeing blue tinge on objects, difficulty telling the difference between blue and green, or difficulty seeing at.  · Proper Use. Drug information provided by: Merative, Micromedex ®. Use this medicine exactly as directed by your doctor. Do not use more of it and do not use it more often than your doctor ordered. If you use too much, the chance of .