3. Direct vasodilators: reduce pressure by dilating resistance vessels (arteries) by
vascular smooth muscle relaxation (e.g., Ca
2+ channel blockers such as verapamil
(4.133) or nifedipine (5.151); vasodilators such as dihydralazine (5.152))
4. Diuretics: lower blood pressure by reducing blood volume and promoting sodium
depletion (e.g., diuretics such as hydrochlorothiazide (5.153))
From a practical clinical perspective, the initial therapy of hypertension involves the
selection of an agent from one of the following four starter groups:
1. Diuretics
2. Beta-blockers
3. ACE inhibitors or AT 1 antagonists
4. Ca
2+ channel antagonists
If the therapeutic results are inadequate, the option is either to change to another drug
in one of the remaining three groups (maintaining one-drug therapy or monotherapy) or
to combine with a drug from one of the remaining three groups (initiating polytherapy).
In severe cases of hypertension, combination therapy is achieved by combining one or
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MEDICINAL CHEMISTRY