Epidemiology and Treatment of Hypertension

Elevated arterial pressure, leading to left ventricle hypertrophy and vascular damage.

Medical approaches to lower high blood pressure

Drugs that block the renin-angiotensin hormonal pathway, reducing blood pressure.

Medications that promote urination, decreasing blood volume and consequently blood pressure.

Drugs that relax blood vessels, lessening peripheral resistance and lowering blood pressure.

Medications that reduce the activity of the sympathetic nervous system, affecting blood pressure.

Drugs that block calcium channels in blood vessels, relaxing the vessels and decreasing blood pressure.

Drugs that block the effects of norepinephrine and epinephrine on beta-adrenergic receptors, influencing heart rate, blood pressure, and other processes.

Different β-blockers vary in their preference for blocking beta-1 receptors, affecting heart function.

Some β-blockers also have a weaker stimulating effect on the sympathetic system.

Certain β-blockers have an ability to widen blood vessels.

Primary effect of β-blockers is lowering high blood pressure.

Unwanted side effects from blocking beta-2 receptors in the body, like narrowing airways.

β-blockers can increase the chances of low blood sugar, mainly in people managing diabetes.

β-blockers can change levels of lipids (fats) in the blood, potentially affecting cholesterol profiles.

Specific situations where a drug should not be used due to potential harm

Potential side effects from suddenly stopping β-blocker use.

Thiazides may lose effectiveness in patients with tachycardia due to adrenergic stimulation of the sinoatrial (SA) node.

Verapamil and diltiazem directly slow heart rate (negative chronotropic effect).

Combining beta-blockers with verapamil or diltiazem may intensify negative chronotropic effects or cause heart block; should be avoided.

Ca2+ channel blockers are often used to treat hypertension, either alone or with other medications.

In combination therapy, amlodipine has shown better results than hydrochlorothiazide when combined with ACE inhibitors.

High sodium levels may contribute to a proinflammatory state, which plays a role in hypertension.

Even small increases in intracellular sodium can significantly affect the contractility of cardiomyocytes.

Individuals with mutations in this gene that reduce renal sodium reabsorption have lower blood pressure.

Combination therapy with different antihypertensive drugs is often used to manage hypertension effectively.

Methyldopa is the preferred drug for hypertension during pregnancy due to its effectiveness and safety for both mother and fetus.

The usual starting dose of methyldopa is 250 mg twice daily, and doses above 2 g/day provide little additional benefit.

Methyldopa can cause sedation, especially when taken at bedtime, but the effect is usually temporary.

Methyldopa can cause adverse effects such as dryness of the mouth, diminished libido, and hormonal changes leading to breast growth and milk production.

Carvedilol is a nonselective beta-blocker with alpha1-antagonist activity, meaning it blocks both beta and alpha receptors in the body.

These are the main α1 blockers used for hypertension management.

An irreversible α blocker used to treat pheochromocytoma, a type of tumor that releases excessive catecholamines.

Atenolol, unlike other β blockers like bisoprolol, carvedilol, metoprolol, and nebivolol, has not been consistently shown to be effective in treating heart failure.

Atenolol might not effectively lower central (aortic) blood pressure when compared to standard brachial artery measurements.

It is unclear whether β blockers other than atenolol have better effects on central blood pressure, arterial stiffness, and endothelial dysfunction.

α1 blockers, like prazosin, terazosin, and doxazosin, are a group of antihypertensive agents.

The detailed workings of α1 blockers are described in Chapter 14.

Phenoxybenzamine, an irreversible α blocker, specifically targets α1 receptors much more than α2 receptors.

Phenoxybenzamine is used to bridge treatment for patients with catecholamine-producing tumors like pheochromocytoma.