Cialis (tadalafil) is a popularly prescribed medicine specially designed for the treatment of erectile dysfunction. It can be used by male patients that need assistance with getting an erection hard enough to have sex. Cialis should be taken with a full glass of water 40-60 minutes before planned sexual activity and you can count on u to 36 hours of efficiency, although the period of time indicated can be different for different people. muscle pain, back pain, flushing, dizziness, headache, nasal stuffiness, pain in arms or legs, vision changes, and stomach upset are most common mild side effects that people experience at the beginning of the treatment. More serious side effect include irregular heartbeat, sweating, shortness of breath, light-headedness, fainting, priapism, sudden hearing loss, vision changes, sudden vision loss, seizure, general ill feeling, chest pain, swelling in your hands, ankles, or feet, and need to be reported straight to your health care provider. Make sure you mention the fact of ever been diagnosed with any medical conditions that may potentially affect the success of your treatment. The following ones are important to mention: heart disease, kidney disease, high or low blood pressure, a history of a heart attack, retinitis pigmentosa, liver disease, stomach ulcer, and congestive heart failure.