• Prazosin (Minipress)
• Doxazosin (Cardura)
• Terazosin (Hytrin)
• Tamsulosin (Flomax)
• Alfuzosin (Uroxatral)
• Silodosin (Rapaflo)

Prazosin, doxazosin, and terazosin were developed to treat high blood pressure. However, the same effect that lowers blood pressure lowers the tension in the muscular valve at the bottom of the bladder, making it easier to pass urine. Over two-thirds of patients with BPH who take these drugs experience rapid improvement in their symptoms without negative effects on their blood pressure.

These drugs are generally well-tolerated. The most common side effects are headache, fatigue, and dizziness. A "first dose" effect may occur that causes blood pressure to drop, which may result in fainting. For this reason, it is recommended that the first pill be taken at bedtime.

There are two different alpha-adrenergic systems, one for the blood pressure and one for the bladder. Tamsulosin (Flomax), alfuzosin (Uroxatral), and silodosin (Rapaflo), types of alpha-adrenergic blocker, are specifically targeted at the bladder and prostate. Therefore, they are less likely to cause low blood pressure or fainting, although these adverse effects can still occur. Other side effects include runny nose, abnormal ejaculation, fatigue, and dizziness. Alfuzonsin (Uroxatral) has been reported to be associated with less risk of abnormal ejaculation. Silodosin (Rapaflo) also works selectively on the bladder and prostate.

• Finasteride (Proscar)
• Dutasteride (Avodart)

Finasteride (Proscar) and dutasteride (Avodart) prevent the formation of the male hormone dihydrotestosterone, which is responsible for the growth of the prostate. These medicines may reduce your symptoms and improve your ability to urinate. Finasteride may also reduce your risk of needing surgery.

Side effects for both of these medicines include changes in your sexual ability or desire and breast enlargement.

• Oxybutynin (Ditropan, Oxytrol)
• Solifenacin (Vesicare)
• Tolterodine (Detrol)
• Darifenacin (Enablex)
• Trospium (Sanctura)
• Fesoterodine (Toviaz)

These drugs work be reducing the strength of bladder contractions. They may relieve symptoms of urgency and frequency. Side effects include dry mouth, constipation , dry eyes, and confusion. They may also cause increased difficulty emptying the bladder in some patients.

Tadalafil [Cialis]

Tadalafil is a medicine that is often prescribed to treat the symptoms of erectile dysfunction (impotence). The Food and Drug Administration (FDA) has recently approved tadalafil as a treatment for BPH, as well. The medicine can reduce symptoms, like difficulty starting to urinate, weak urination stream, and the urge to urinate frequently.

Potential side effects of tadalafil include flushing, headache, stomach upset, back pain, and congestion.

Note: You should not take tadalafil if you are also taking nitrates (eg, nitroglycerin) because your blood pressure may become dangerously low. Also, tadalafil should not be taken in combination with alpha-blockers.

Research has shown that using alpha-blockers with dihydrotestosterone reducers may work better than using either drug alone in men with larger prostates. This type of therapy, called combination therapy, can decrease the development of complications and the need for surgical intervention. For instance, Jalyn is a medication that contains both tamsulosin and dutasteride, a 5-alpha reductase inhibitor.

Certain over-the-counter medicines, notably antihistamines and sleeping pills that contain alpha-adrenergic products, and several kinds of prescription medicine (anticholinergic and narcotic) can cause a worsening of urine flow. These medicines can even lead to complete urinary obstruction in patients with BPH. Read labels carefully and check with your physician before you take any new medicines or supplements.

A special precaution is issued for the use of alpha-blockers with medicines used to treat erectile dysfunction. These medicines include:

• Tadalafil (Cialis)
• Sildenafil (Viagra)
• Vardenafil (Levitra)

When taken together, these medicines may cause a drop in blood pressure.