- Erection that will not go away (priapism). If you have an erection that lasts more than 4 hours, seek medical help immediately. Priapism can permanently damage your penis.
- Sudden vision loss in one or both eyes. Sudden vision loss in one or both eyes can be a sign of a serious eye problem called non-arteritic anterior ischemic optic neuropathy (NAION). Stop taking Cialis and call your healthcare provider right away if you have sudden vision loss in one or both eyes.
- Sudden hearing decrease or hearing loss. Some people may also have ringing in their ears (tinnitus) or dizziness. If you experience these symptoms, stop taking Cialis and contact a doctor right away.
For a full list of side effects, please read the patient information leaflet.