Cialis for daily use, is approved to treat both erectile dysfunction and the urinary symptoms of bph, like needing to go frequently, day or night. tell your doctor about all your medical conditions and medicines, and ask if your heart is healthy enough for sex. do not take cialis if you take nitrates for chest pain, as it may cause an unsafe drop in blood pressure. do not drink alcohol in excess. side effects may include headache, upset stomach, delayed backache or muscle ache. to avoid long-term injury, get medical help right away for an erection lasting more than four hours. if you have any ...