Drug Interaction Report

Using prazosin and carvedilol together can have increased effects on your blood pressure. You may be more likely to experience side effects such as dizziness, weakness, headache, flushing, fainting, and irregular heartbeat, especially if you have been on carvedilol and are starting treatment with prazosin. These effects may also occur following a dose increase of prazosin or when prazosin is restarted after an interruption. Let your doctor know if you develop these symptoms and they do not go away after a few days or they become troublesome. You may need a dose adjustment or more frequent monitoring of your blood pressure to safely use both medications. Taking the prazosin dose just before going to bed may help. Avoid driving or operating hazardous machinery until you know how these medications affect you, and use caution when getting up from a sitting or lying position. It is important to tell your doctor about all other medications you use, including vitamins and herbs. Do not stop using any medications without first talking to your doctor.

Ask your doctor before using prazosin together with ethanol (alcohol). Using prazosin with ethanol (alcohol) can lower your blood pressure. This can cause dizziness or feeling like you might pass out, especially when getting up from a sitting or lying position. This may be more likely to occur when you first start taking either of these medications. You may need a dose adjustment or need your blood pressure checked more often if you take both medications. You may develop flushing, warmth or redness under your skin or tingly feeling after alcohol intake (especially in you are of Asian descent) and should be advised to avoid alcohol or limit your intake. It is important to tell your doctor about all other medications you use, including vitamins and herbs. Do not stop using any medications without first talking to your doctor.