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.
Blood pressure: The first few doses of terazosin can cause extreme lowering of blood pressure, especially when moving from a lying or sitting position to a standing position. Sometimes even loss of consciousness can occur. A similar effect may occur if the medication is taken again after stopping it for more than a few doses, if the dose is rapidly increased, or if another blood-pressure-lowering medication is added.
The likelihood of this effect can be minimized by starting the dose of terazosin at 1 mg at bedtime, by increasing the dosage slowly, and by starting any additional blood-pressure-lowering medications with caution. If you are also taking phosphodiesterase 5 inhibitors (e.g., sildenafil, tadalafil, vardenafil) discuss with your doctor whether any special monitoring is needed.
While temporary loss of consciousness is the most severe blood-pressure-lowering effect of terazosin, other symptoms of lowered blood pressure, such as dizziness, lightheadedness, and palpitations are more common. If these symptoms occur, lie down and wait for a few minutes before standing to prevent their recurrence, then get up very gradually.
Disease progression: Terazosin does not slow or stop the progression of enlarged prostate.
Drowsiness/reduced alertness: Because of the risk of extreme lowering of blood pressure, avoid driving or hazardous tasks for 12 hours after the initial dose of terazosin, after the dose is increased, and after interruption of therapy when treatment is resumed.
Avoid situations where dizziness, lightheadedness, or temporary loss of consciousness could result in injury.
Fainting: Terazosin can cause extreme lowering of blood pressure and possibly fainting. If you have a history of micturition syncope (a condition where fainting occurs during or after urination), you should not take terazosin. Talk to your doctor if you have any concerns.
Kidney, bladder, and urinary problems: If you have reduced kidney function, bladder problems, or urinary problems, 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.
Prostate cancer: Prostate cancer and enlarged prostate (BPH) have many of the same symptoms and it is possible for men to have both diseases at the same time. Terazosin is not used to treat prostate cancer. Your doctor may perform tests to rule out prostate cancer before starting you on terazosin treatment.
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: It is not known if terazosin passes into breast milk. If you are a breast-feeding mother and are taking this medication, 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.
Seniors: People over 65 years of age may be at an increased risk of blood pressure decreases, especially when moving from a lying or sitting position to a standing position.