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Antihypertensive drugs that interact with adrenoceptors have certain advantages and disadvantages (on the treatment of hypertension). Alpha-1 antagonists such as prazosin have favorable effects on plasma lipids but may produce excessive postural falls in blood pressure, particularly following the initial dose. Recently developed alpha-1 antagonists (doxazosin, terazosin) have longer durations of action than prazosin, allowing less frequent administration. Beta blockers may be cardioprotective but in contrast to alpha-1 antagonists tend to have adverse effects on plasma lipids. Drugs with combined beta and alpha-1 blocking activity such as labetalol have favorable metabolic effects but postural hypotension remains a problem. Recently developed drugs with different alpha-1/beta blocking ratios that differ from labetalol may prove to be more popular clinically. Several beta blockers with vasodilator activity which is not due to alpha-1 blockade have also been developed. These drugs appear to have favorable metabolic effects similar to drugs with alpha-1 blocking activity, but do not cause postural hypotension. |
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