Before you begin using a medication, be sure to inform your doctor of any medical conditions or allergies you may have, any medications you are taking, whether you are pregnant or breast-feeding, and any other significant facts about your health. These factors may affect how you should use this medication.
Drowsiness/reduced alertness: This medication can cause severe dizziness and lightheadedness. Avoid driving or operating dangerous machinery until you determine how this medication affects you. Speak with your doctor if you experience severe dizziness or lightheadedness while taking prazosin.
Kidney problems: If you have reduced kidney function, discuss with your doctor how this medication may affect your medical condition, how your medical condition may affect the dosing and effectiveness of this medication, and whether any special monitoring is needed.
Orthostatic hypotension: Prazosin has been known to cause severe dizziness and even loss of consciousness for people moving from a sitting or lying position to a standing position. This is known as orthostatic hypotension. It happens most commonly if the person is already taking another blood pressure-lowering medication, has just started treatment with prazosin, or starts treatment with prazosin at a higher dose.
To help prevent this, get up slowly from a sitting or lying position. Your doctor will also recommend slowly increasing the dose of prazosin.
Pregnancy: This medication should not be used during pregnancy unless the benefits outweigh the risks. If you become pregnant while taking this medication, contact your doctor immediately.
Breast-feeding: This medication passes into breast milk. If you are a breast-feeding mother and are taking prazosin, it may affect your baby. Talk to your doctor about whether you should continue breast-feeding.
Children: The safety and effectiveness of using this medication have not been established for children under 12 years of age.