Yes Tamsulosin might cause dizziness but it is rare and might occur only during initial days of treatment. Your doctor had presctibed this medicine as he had judged that the benefit of this drug outweighs it s side effects in your case. You ought to be careful not to do work like driving which need your constant alertness. Avoid standing for long periods of time or becoming overheated during exercise and in hot weather. Avoid getting up too fast from a sitting or lying position, or you may feel dizzy. If you feel dizzy constantly , or experience side effects like fainting, cough or hoarseness ,fever or chills, lower back or side pain, painful or difficult urination check with your doctor.