Cialis (tadalafil) is a prescription anti-impotence medication often prescribed for men suffering from repeated inability to get a stable erection and complete sexual intercourse. Cialis should be taken when needed, but you have to avoid using it more often than every 24 hours. Otherwise serious consequences are possible. The following symptoms of an overdose will nee to be reported to your local emergency center if you get them after taking too much of Cialis: ringing in ears, rash, loss of hearing, chest pain, erection that lasts longer than 4 hours, dizziness, blurred vision, hives, and changes in color vision. Serious side effects are rare but possible, primarily because some people fail to mention their medical conditions that may be worsened by the fact of using Cialis. Your doctor will need to know if you have penis angulation, stomach or intestine ulcers, liver, kidney, or heart disease, diabetes, cavernosal fibrosis, irregular heartbeat, Peyronie's disease, any bleeding disorder, a heart attack, low blood pressure, stroke, chest pain, high cholesterol, blood cell problems, or high blood pressure to be able to prescribe lowest efficient and safe dose.