The body takes longer to absorb it after a high-fat meal or alcohol. Some examples of nitrates are nitroglycerin Nitro-Dur, Nitrostat, others , isosorbide mononitrate Monoket and isosorbide dinitrate Bidil. The most popular options currently available include Viagra, Levitra, and Cialis. Often, these are prescribed for chest pain called angina. Psychological factors like stress, depression, or anxiety can also contribute.Sildenafil price. As with all medications, the cost of sildenafil can vary. Factors that may affect the price you’ll pay include your treatment plan, your insurance coverage, the form your.  · For treatment of erectile dysfunction: For oral dosage form (tablets): Adults up to 65 years of age—50 milligrams (mg) as a single dose no more than once a day, 1 hour before sexual intercourse. Alternatively, the medicine may be taken 30 minutes to 4 hours before sexual intercourse. Your doctor may adjust your dose if needed. You take drugs like sildenafil (Viagra), vardenafil (Levitra, Staxyn) and tadalafil (Cialis, Adcirca) as pills before you have sex. They work by increasing blood flow in your penis. They work by.