It is very important that your doctor check your progress at regular visits to make sure that this medicine is working properly and to check for unwanted effects.
Dizziness, lightheadedness, or fainting may occur after you take this medicine, especially when you get up from a lying or sitting position. Getting up slowly may help lessen this problem. If you feel dizzy, lie down so you do not faint. Then sit for a few moments before standing to prevent the dizziness from returning.
Because tamsulosin may cause some people to become dizzy or feel faint, make sure you know how you react to this medicine before you drive, use machines, or do anything else that could be dangerous if you are dizzy or not alert.
This medication may rarely cause a severe allergic reaction (swelling of face, tongue, or throat, difficulty breathing, and blistering of the skin. Check with your doctor immediately if this occurs.
You should seek medical attention right away if you experience a prolonged erection while using this medicine. This is an extremely rare unwanted effect that must be treated right away to prevent permanent erectile damage (impotence).
If you plan to have cataract surgery, tell your eye doctor (ophthalmologist) that you are taking this medicine or that you used this medicine in the past 9 months. A serious eye problem called Intraoperative Floppy Iris Syndrome (IFIS) has occurred in some patients who were taking this medicine or who had recently taken this medicine when they had cataract surgery.
Do not take other medicines unless they have been discussed with your doctor. This includes prescription or nonprescription (over-the-counter [OTC]) medicines and herbal or vitamin supplements.