You will find a full list in the manufacturer’s information leaflet supplied with your medicine. These include a heart attack, stroke or a serious heart rhythm disorder in the past six months. This medication is taken with or without food an hour before sex. Do not use in larger or smaller amounts or for longer than recommended. To avoid dizziness and lightheadedness when rising from a seated or lying position, get up slowly. Because appointments can be brief and there’s often a lot of ground to cover, it’s a good idea to be well prepared. You can take the tablet either before or after food but, if you have just eaten a large or high-fat meal, it may take longer for it to work.How does Levitra work? The active ingredient of Levitra, vardenafil, belongs to a group of medicines called phosphodiesterase-type-5 (PDE5) inhibitors. It works by blocking the phosphodiesterase enzyme, which normally breaks down a substance known as cyclic guanosine monophosphate (cGMP). Vardenafil is used to treat male sexual function problems (impotence or erectile dysfunction-ED). In combination with sexual stimulation, vardenafil w. Vardenafil is a medication that treats erectile dysfunction. ED is the inability to achieve and sustain an erection suitable for sexual intercourse. This medication works by increasing blood flow to your penis, which helps you maintain an erection.