Drug information provided by: Merative, Micromedex®
It is very important that your doctor check your progress at regular visits to make sure that this medicine is working properly. Blood and urine tests may be needed to check for unwanted effects.
Dizziness, lightheadedness, or fainting may occur after you use 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.
You may also have dizziness, lightheadedness, or fainting if you drink alcohol, stand for a long time, exercise or if the weather is hot. While you are taking this medicine, be careful to limit the amount of alcohol you drink. Drink plenty of fluids if you exercise or sweat more than usual while you are using this medicine.
Prazosin may cause some people to become dizzy, drowsy, or less alert than they are normally. 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, drowsy, or are not alert.
Make sure any doctor or dentist who treats you knows that you are using this medicine. This medicine may affect the results of certain medical tests.
Call your doctor right away if you have a prolonged erection of the penis while you are using this medicine. It must be treated right away to prevent permanent impotence.
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.