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 sudden decrease or loss in hearing or vision, or any symptoms of an allergic reaction, stop taking cialis and get medical help right away. ask your doctor about cialis for daily use and a free 30-tablet trial. things we build and it'sit doesn't even fly.zing we build it in classrooms and exhibit halls, mentoring tomorrow's innovators. we build it raising roofs, preserving habitats and serving america's veterans. every day, thousands of boeing volunteers help make their communities the best they can be. building something better for all of us.