(HydroDIURIL), a thiazide, is the most frequently prescribed diuretic to control
mild hypertension.
Thiazides are not used in patients who have renal insufficiency. Loop diuret-
ics, such as furosemide (Lasix), are usually recommended for these patients
because they do not depress renal flow.
Diuretics are not used if hypertension is the result of renal-angiotensin-
aldosterone involvement because these drugs tend to elevate the serum renin
level. Hydrochlorothiazides are combined with beta blockers, and angiotensin-
converting enzyme (ACE) inhibitors. ACE inhibitors tend to increase serum potas-
sium (K) levels. When they are combined with the thiazide diuretic, serum
potassium loss is minimized.
Sympathetic depressants (sympatholytics)
Sympatholytics (see Chapter 15) are divided into five groups. These are
- Beta-adrenergic blockers: (acebutolol HCL (Sectral), atenolol (Tenormin),
metoprolol (Lopressor), Nadolol (Corgard), propranolol (Inderal). - Centrally acting sympatholytics (adrenergic blockers): clonidine HCl
(Catapres) methyldopa (Aldomet). - Alpha-adrenergic blockers: phentolamine (Regitine); doxazosin mesylate
(Cardura), terazosin HCl (Hytrin). - Adrenergic neuron blockers (peripherally acting sympatholytics): guanethi-
dine monosulfate (Ismelin), resperine (Serpasil). - Alpha- and beta-adrenergic blockers: carteolol HCl (Cartrol, Ocupress).
Direct-acting arteriolar vasodilators
Direct-acting arteriolar vasodilators are Step 3 drugs that act by relaxing the
smooth muscles of the blood vessels—mainly the arteries—causing vasodilation.
Direct-acting arteriolar vasodilators promote an increase in blood flow to the
brain and kidneys. Diuretics can be given with direct-acting vasodilators to
decrease edema. Reflex tachycardia is caused by vasodilation and the decrease in
blood pressure. Beta blockers are frequently prescribed with arteriolar vasodila-
tors to decrease the heart rate, counteracting the effect of reflex tachycardia.
Nitroprusside and diazoxide are prescribed for acute hypertensive emergencies.
A list of drugs utilized in the treatment of hypertension is provided in the
Appendix. Detailed tables show doses, recommendations, expectations, side
effects, contraindications, and more; available on the book’s Web site (see URL
in Appendix).
CHAPTER 19 Cardiac Circulatory Medications^357