Patients taking terazosin to treat high blood pressure or an enlarged prostate may experience several common side effects. One of the most frequent complaints from patients on this drug is feelings of dizziness or lightheadedness, particularly after standing up. Many people find that it makes them feel fatigued, weak, or drowsy. Some suffer from nasal congestion and headache when taking it, while others may feel nauseated from it. Some other common terazosin side effects can include swelling in the extremities, a fast, pounding, irregular heartbeat, and problems with sexual function.
For many people, terazosin side effects include dizziness and lightheadedness, particularly when they first begin taking the drug, or if they are on a high dose. It is often the result of postural hypotension, where the person's blood pressure drops dramatically after they move from a lying or sitting position to standing. In severe cases, the person may even faint suddenly. Many patients complain that their vision becomes blurred while taking terazosin as well.
Feelings associated with being tired are also very common terazosin side effects. Patients may notice that they are suffering from fatigue and have a lack of energy, and their muscles may even feel weak. Some may also tend to become very drowsy and want to sleep more than normal.
Terazosin can often cause those using it to feel generally sick. One frequent side effect is congestion and a stuffy nose. Many patients complain of headaches when taking terazosin. Others might find that it makes them feel nauseated, and for some it may even cause vomiting.
There are several other terazosin side effects that can also affect patients. Swelling can occur from edema, particularly in the feet, legs, and hands, and some people also find that they have pain, burning, or numbness in their extremities as well. Patients may find that they gain weight while on this medication, and they can have pain in their back or joints. Some people may experience a heartbeat that is fast and pounding, or have heart palpitations, and they may also have chest pain or experience a shortness of breath.
Terazosin can have negative effects on sexual function as well. Some people many notice a decrease in their libido. Men can experience either impotence or a prolonged, painful erection that will not go away for several hours.