Daily dosing for ED: 2. Age greater than 50 years or Coronary artery disease or Hyperlipidemia high lipids or fats in the blood or Hypertension high blood pressure or Low cup to disc ratio eye condition also called “crowded disc” or Smoking—Use with caution. In addition to alpha blockers, we commonly hear that Cialis should not be taken with nitrates, as the combination could result in a significant and potentially serious drop in blood pressure. Cialis with food Cialis can be taken with or without food. Also, do not stop taking this medicine without checking first with your doctor.Yes, Cialis in higher dosages can last up to 36 hours, while Viagra commonly lasts up to 4 hours. Talk with your doctor to see which medication best fits .  · One dose of Cialis can help improve erectile function for up to 36 hours. In comparison, Viagra’s effects can last up to 4 hours. But on average, its effects start to .  · When using this medicine for erectile dysfunction, the ability to have sexual activity may be improved for up to 36 hours after taking the tablet. Use only the brand of .