Levitra (vardenafil) is supposed to be taken only by people with erectile dysfunction - which also means they first have to see their doctor and get a prescription. Unless there are any directions provided by your doctor, you are not expected to follow any particular diet. An exception to that might be the fact you shouldn't really consume grapefruit juice or any other grapefruit products. Some of the side effects Levitra may cause include headache, heartburn, dizziness, flushing, upset stomach, runny or stuffy nose and some other ones. Your health care provider needs to know as much as possible about your health condition before prescribing Levitra to make sure you will benefit from the treatment and will not experience any unpleasant side effects. Make sure you take Levitra exactly as prescribed by your doctor.