Stop using vardenafil and call your doctor at once if you have: ringing in your ears, or sudden hearing loss; irregular heartbeat; swelling in your hands, ankles, or feet; shortness of breath; a light-headed feeling, like you might pass out; or seizure convulsions. When oral medications might not be safe Check with your health care team before you take any medicine for erectile dysfunction. This boosts blood flow and helps you get an erection from sexual activity. Common side effects may include: flushing sudden warmth, redness, or tingly feeling ; stuffy nose, sinus pain; upset stomach; or back pain. Get emergency medical help if you have signs of an allergic reaction: hives; difficult breathing; swelling of your face, lips, tongue, or throat. Tadalafil Cialis. This medicine works best when you take it on an empty stomach an hour before sex.Viagra, Cialis, Levitra, and Stendra are oral medications used to treat erectile dysfunction (ED). You may also know them by their generic names: sildenafil . Levitra is not a cure for ED and you still need to be aroused for the medication to work. Levitra and its generic version are available in doses of: . Follow the directions on the prescription label. You may take this medication with or without meals. The dose is usually taken 1 hour before sexual activity. You should not .