Do not use Doxazosin if:

• you are allergic to any ingredient in Doxazosin or to similar medicines (e.g., prazosin).

• Doxazosin may cause drowsiness or dizziness. These effects may be worse if you take it with alcohol or certain medicines. Use Doxazosin with caution. Do not drive or perform other possibly unsafe tasks until you know how you react to it.
• Dizziness or lightheadedness may occur if you stand up too fast from lying or sitting. If this occurs, get up slowly and avoid sudden posture changes. These effects will more likely occur while you are taking the first few doses or if you have increased your dose, but can occur at any time while you are taking Doxazosin. They can also occur if you stop taking the medicine and restart treatment.
• Emsam may cause dizziness, lightheadedness, or fainting; alcohol, hot weather, exercise, or fever may increase these effects. To prevent them, sit up or stand slowly, especially in the morning. Sit or lie down at the first sign of any of these effects.
• Before drinking alcohol, discuss it with your doctor. Alcohol may worsen dizziness and lightheadedness.
• Be careful during exercise, hot weather, and if you must stand for long periods of time.
• Avoid situations where fainting could cause injury. If fainting occurs, lie down and stop taking this medication until you talk with your doctor.
• Doxazosin may rarely cause a prolonged, painful erection. This could happen even when you are not having sex. If this is not treated right away, it could lead to permanent sexual problems such as impotence. Contact your doctor right away if this happens.
• Patients who take medicine for high blood pressure often feel tired or run down for a few weeks after starting treatment. Be sure to take your medicine even if you may not feel normal. Tell your doctor if you develop any new symptoms.
• Lab tests, including blood pressure, may be performed while you use Doxazosin . These tests may be used to monitor your condition or check for side effects. Be sure to keep all doctor and lab appointments.
• If you become pregnant, contact your doctor. You will need to discuss the benefits and risks of using Doxazosin while you are pregnant. It is not known if Doxazosin is found in breast milk. If you are or will be breast-feeding while you use Doxazosin , check with your doctor. Discuss any possible risks to your baby.

Check with your doctor if any of these most common side effects persist or become bothersome:

• back pain; diarrhea; dizziness; drowsiness; dry mouth; feeling of a whirling motion; flu-like symptoms; headache; indigestion; lightheadedness; nasal congestion; nausea; pain; stomach pain; swelling; tiredness.

• severe allergic reactions (rash; hives; itching; difficulty breathing; tightness in the chest; swelling of the mouth, face, lips, or tongue); blurred vision; chest pain; fainting; painful and prolonged penile erection; pounding in the chest; puffiness in hands or feet; swelling of eyelids.

Doxazosin is to be used only by the patient for whom it is prescribed. Do not share it with other people.
If your symptoms do not improve or if they become worse, check with your doctor.