Hypotension first-dose, with antihypertensives

Generally, arblockers are considered as second-line agents to be added on to most other agents when hypertension is not adequately controlled. They may have a specific role in the antihypertensive regimen for elderly males with prostatism however, their use is often curtailed by complaints of syncope, dizziness, or palpitations following the first dose and orthostatic hypotension with chronic use. The roles of doxazosin, terazosin, and prazosin in the management of patients with hypertension are limited due to the paucity of outcome data and the absence of a unique role for special populations or compelling indications from JNC 7. 

First-dose syncope (hypotension with sudden loss of consciousness) may occur 30 to 90 minutes following initial dose of more than 2 mg, a too-rapid increase in dosage, or addition of another antihypertensive agent to therapy. First-dose syncope may be preceded by tachycardia (pulse rate of 120-160 beats/minute). 

Hypotension A steep faU in blood pressure may occur following the first dose of an ACE inhibitor in patients with elevated PRA. Special care should be exercised in patients who are salt-depleted, in patients being treated with multiple antihypertensive drugs, and in patients who have congestive heart failure. Such patients should be started on very small doses of ACE inhibitors, or salt intake should be increased and diuretics stopped before beginning therapy. 

The hypotensive effect of antihypertensives can be enhanced by other antihypertensives, as would be expected. Although first-dose hypotension (dizziness, lightheadedness, fainting) can occur with some combinations, the additive effects are usually clinically useful. Perhaps of more concern is the use of antihypertensives with drugs that have hypotension as an adverse effect, where the effects may not be anticipated. Some drugs antagonise the blood pressure-lowering effects of the antihypertensives and shouid therefore be used with caution. 

The hypotensive effect of reserpine is used in severe hypertension, nowadays in low doses in combination with other antihypertensives. Its sedative and relaxant effect has been used in the treatment of psychoses. Reserpine was the first useful remedy in the treatment of psychosis and opened up the road for modern psychopharmacotherapy, which has drastically changed the treatment of psychiatric patients. 

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