Differences Between Alpha-Blocker Drugs
Clinical trials show that there is not much difference in the effect on symptoms or urinary flow rates among terazosin (Hytrin®), doxazosin (Cardura®), tamsulosin (Flomax®), or alfuzosin (Xatral®). Therefore, the deciding factor in selecting an alpha-blocker drug is often the side-effect profiles.
Alfuzosin (especially the sustained-release formulation) and tamsulosin seem to be better tolerated than terazosin and doxazosin. Twice as many men withdrew from trials of terazosin and doxazosin than withdrew from alfuzosin and tamsulosin trials.
Terazosin and doxazosin have a tendency to reduce blood pressure at the dosages used to treat BPH and need to be started slowly, gradually building up to the maximum dosage, which generally takes about 4 to 6 weeks. Because these drugs have a greater cardiovascular effect, they cause more postural hypotension (dizziness and instability when rising from a seated or lying position) than other drugs. Fatigue also occurs slightly more often with terazosin and doxazosin than with tamsulosin, while the headaches that can occur with doxazosin and terazosin do not appear with tamsulosin -- at least not when compared to placebos. Dizziness, fatigue, and postural hypotension can be reduced by taking the drug at bedtime.
Patients with hypertension may need to adjust their blood pressure drugs if they are taking either terazosin or doxazosin because these drugs tend to lower blood pressure. Tamsulosin does not lower blood pressure even in men with high blood pressure.
The disadvantage of tamsulosin is that it causes more nasal congestion and retrograde ejaculation than other alpha-blockers. While these side effects can be annoying, they are not overly serious, and retrograde ejaculation does not affect a man’s ability to enjoy sex.
