How do blood pressure drugs work and how can I find the one that’s right for me?

DEAR DOCTOR K:

How do blood pressure drugs work? And how will my doctor know which one is right for me?

DEAR READER:

There are many different drugs for blood pressure and they work in different ways. Finding which one will work best for you may involve a process of trial-and-error. But in the end, you’ll be rewarded with a medication that offers the best blood pressure control with the fewest side effects.

If you have other health conditions — diabetes and heart disease often accompany hypertension, for instance — certain drugs can lower blood pressure while also helping to treat these conditions.

I’ll briefly summarize the different classes of blood pressure drugs and how they work. I won’t go into the potential side effects of these drugs here, but you should discuss them with your doctor. (I’ve put tables with examples of the different types of drugs at the end of this post.)

  • Diuretics, or “water pills,” help the kidneys eliminate sodium and water from the body. This decreases blood volume, so the heart has less to pump with each beat. Of all the blood pressure drugs used today, diuretics have been around the longest and their beneficial effects are solidly proven.
  • ACE inhibitors decrease blood volume by preventing the kidneys from retaining sodium and water. They do this by deactivating angiotensin-converting enzyme (ACE). ACE is a natural chemical (an enzyme) that converts another natural chemical, angiotensin I, to the chemical called angiotensin II. Angiotensin I is inactive, but angiotensin II raises blood pressure. So reducing the amount of angiotensin II by reducing ACE, the enzyme that makes angiotensin II, helps lower blood pressure.
  • Angiotensin-receptor blockers (ARBs) block the blood pressure-raising effects of angiotensin II. So, the ACE inhibitors reduce the amount of angiotensin II the body makes, and the ARBs reduce the blood pressure-raising effect of angiotensin II.
  • Calcium-channel blockers slow the movement of calcium into the smooth-muscle cells that are in the heart and the walls of the blood vessels. This makes heart muscle pump less forcefully (but still forcefully enough), which reduces blood pressure. Calcium-channel blockers also relax the muscle in the blood vessel walls, which makes blood vessels open wider, lowering blood pressure.
  • Anti-adrenergics limit the action of the hormones epinephrine and norepinephrine. This relaxes the blood vessels and reduces the speed and force of the heart’s contractions.
  • Direct-acting vasodilators relax the arteries. They act quickly and are often used in emergencies.
  • Direct renin inhibitors inhibit the activity of renin, the enzyme largely responsible for angiotensin II levels. Aliskiren (Tekturna) is a renin inhibitor.

There really is no “best” blood pressure medication. The goal is to find the right medication for you. Often, more than one type of medicine used in combination proves the best. That means finding the medicine or medicine combo that effectively lowers your blood pressure while not causing side effects — and not costing more than you can afford.

Diuretics

Class Generic name Brand name Side effects
Thiazide diuretics chlorothiazide Diuril Weakness, confusion, potassium depletion, gout, fatigue, thirst, frequent urination, lightheadedness, muscle cramps, diarrhea or constipation, increased sensitivity to sunlight, allergic reaction in people allergic to sulfa drugs, impotence.
chlorthalidone Hygroton
hydrochlorothiazide Esidrix, HydroDiuril, Microzide
indapamide Lozol
metolazone Mykrox, Zaroxolyn
Loop diuretics bumetanide Bumex Weakness, confusion, potassium depletion, gout, fatigue, thirst, diarrhea or constipation, increased sensitivity to sunlight, allergic reaction in people allergic to sulfa drugs, impotence.
ethacrynic acid Edecrin
furosemide Lasix
torsemide Demadex
Potassium-sparing diuretics/aldosterone-receptor blockers* amiloride Midamor Excessive potassium levels, especially in patients with kidney disease; breast enlargement and erectile dysfunction in men; menstrual irregularities in women.
spironolactone Aldactone
triamterene Dyrenium
eplerenone Inspra Headache, dizziness, diarrhea, fatigue, upset stomach, and breast enlargement or tenderness.
*Note: Potassium-sparing diuretics also directly or indirectly block aldosterone, a hormone that raises blood pressure by causing the kidneys to conserve sodium and water. As a result, these four medications are sometimes also known as aldosterone-receptor blockers. Amiloride (Midamor), spironolactone (Aldactone), and triamterene (Dyrenium) also affect other hormones and thus carry some unwanted side effects, such as breast enlargement and impotence in men and menstrual irregularities in women.

 

Anti-adrenergic drugs

Class Generic name (Brand name) Side effects
Beta blockers (cardioselective)
  • acebutolol (Sectral)
  • atenolol (Tenormin)
  • betaxolol (Kerlone)
  • bisoprolol (Zebeta)
  • metoprolol (Lopressor)
  • metoprolol extended release (Toprol-XL)
  • nebivolol (Bystolic)
  • penbutolol (Levatol)
Wheezing, dizziness, depression, impotence, fatigue, insomnia, decreased HDL cholesterol levels, lower exercise tolerance. Can worsen peripheral vascular disease and heart failure. Abrupt withdrawal may trigger angina or a heart attack in patients with heart disease.
Beta blockers (nonselective)
  • nadolol (Corgard)
  • pindolol (Visken)
  • propranolol (Inderal, Inderal LA)
  • sotalol (Betapace)
  • timolol (Blocadren)
Alpha-1 blockers
  • doxazosin (Cardura)
  • prazosin (Minipress)
  • terazosin (Hytrin)
A drop in blood pressure upon standing up, fainting, weakness, heart palpitations, headache, nasal congestion, dry mouth.
Alpha and beta blockers
  • carvedilol (Coreg)
  • labetalol (Normodyne, Trandate)
Wheezing, depression, insomnia, diarrhea, lightheadedness, dizziness, unusual tiredness or weakness, drying of the eyes, erectile dysfunction, headache, dry mouth, nasal congestion, decreased HDL cholesterol levels, lower exercise tolerance, a drop in blood pressure upon standing up, fainting, heart palpitations. Can worsen peripheral vascular disease and heart failure. Abrupt withdrawal may trigger angina or a heart attack in patients with heart disease.
Centrally acting agents
  • clonidine (Catapres, Catapres-TTS)
  • methyldopa (Aldomet)
A drop in blood pressure upon standing up, drowsiness, sedation, dry mouth, fatigue, erectile dysfunction, depression, dizziness. Catapres-TTS (a patch) may cause a rash.
Peripheral nerve–acting agents
  • guanethidine (Ismelin)
  • reserpine (Serpalan)
A drop in blood pressure upon standing up, depression, nasal stuffiness, nightmares. Guanethidine may slow heart rate, and reserpine may cause indigestion.

 

Direct-acting vasodilators

Generic name Brand name Side effects
hydralazine Apresoline Headaches, palpitations, weakness, flushing, nausea. Minoxidil may cause hair growth, fluid retention, and increased blood sugar.
minoxidil Loniten

 

Calcium-channel blockers

Generic name Brand name Side effects
amlodipine Norvasc Headache, dizziness, edema, and heartburn. Nifedipine can cause palpitations. Diltiazem and verapamil can cause constipation and a slowed heartbeat.
diltiazem Cardizem, Dilacor, others
felodipine Plendil
isradipine DynaCirc
nicardipine Cardene, Cardene SR
nifedipine Adalat CC, Procardia XL
verapamil Calan, Isoptin, others

 

ACE inhibitors

Generic name Brand name Side effects
benazepril Lotensin Cough, rash, fluid retention, high potassium levels, and loss of taste. May cause low blood pressure and fainting. Can worsen kidney impairment if narrowed arteries feed both kidneys. May cause spontaneous abortion.
captopril Capoten
enalapril Vasotec
fosinopril Monopril
lisinopril Prinivil, Zestril
quinapril Accupril
ramipril Altace

 

Angiotensin-receptor blockers (ARBs)

Generic name Brand name Side effects
azilsartan medoxomil Edarbi Muscle cramps, dizziness.
candesartan Atacand
eprosartan Teveten
irbesartan Avapro
losartan Cozaar
olmesartan Benicar
telmisartan Micardis
valsartan Diovan