First, an overview of the 8 classes of high blood pressure drugs, how they work, and their common "listed" side effects:
ACE inhibitors - [Accupril (Quinapril); Aceon (Perindopril); Altace (Ramipril); Lotensin (Benazepril); Capoten (Captopril); Vasotec (Enalapril); Monopril (Fosinopril); Prinivil, Zestril (Lisinopril); Univasc (Moexipril); Mavik (Trandolapril)]
Function: Angiotensin-converting enzyme (ACE) inhibitors prevent your body from making Angiotensin II - a natural substance our bodies produce that, among other things, can cause our blood vessels to narrow, thicken and stiffen. Angiotensin II also triggers the release of a hormone associated with increased water and sodium in the body.
The most common side effect is a dry cough. Rarer side effects include: Lightheadedness, dizziness, rash, reduced appetite, increased blood potassium, changes in the flavor of foods and swelling. ACE inhibitors are also associated with birth defects. Some pain relievers reduce the effectiveness of ACE inhibitors.
Alpha Blockers - [Cardura (Doazosin); Minipress (Prazosin); Hytrin (Terazosin); Flomax (Tamsulosin); Uroxatral (Alfuzosin)]
Function: These drugs stop the hormone norepinephrine (noradrenaline) from constricting the muscles that surround the veins, smaller arteries and other muscles throughout the body.
Side effects: "First-dose effect" - when first taking Alpha Blockers, some people get dramatically reduced blood pressure, dizziness and feeling faint when sitting up or standing up. Additional side effects include: headache, pounding heartbeat, nausea, weakness, and weight gain.
Angiotensin II receptor blockers - [Atacand (Candesartan); Teveten (Eprosartan); Avapro (Irbesarten); Cozaar (Losarten); Benicar (Olmesarten); Micardis (Telmisartan); Diovan (Valsartan)]
Function: These drugs block the action (not the production) of Angiotensin II - (see above under ACE inhibitors for more information on Angiotensin II).
Side effects (relatively rare) include: Diarrhea, dizziness, headache, lightheadedness, back and leg pain, sinus congestion, kidney failure, liver failure, allergic reaction, lowered white blood cells, and swelling. Angiotensin II receptor blockers are also associated with birth defects.
Beta Blockers - [Sectral (Acebutolol); Tenormin (Atenolol); Zebeta (Bisoprolol); Coreg (Cardedilol); Lopressor, Toprol XL (Metoprolol); Corgard (Nadolol); Bystolic (Nebivolol); Inderal LA (Propranolol)]
Function: Beta-blockers (beta-adrenergic blocking agents) block adrenaline (epinephrine), causing the heart to slow and blood vessels to open.
Common side effects include: Cold hands, dizziness, fatigue, and weakness. Less common side effects include: Depression, reduced libido (sex drive), insomnia (trouble sleeping), and shortness of breath. Beta-blockers may cause severe asthma attacks. They can also block indications of low blood sugar (like a racing pulse) in diabetics. Beta-blockers can affect cholesterol and triglyceride levels, typically temporarily. Abrupt discontinuation of beta-blockers can increase risk of heart attack and other heart issues.
Calcium channel blockers - [Norvasc (Amplodipine); Cardizem LA, Dilacor XR, Tiazac (Diltiazem); Plendil (Felodipine); DynaCirc CR (Isradipine); Cardene, Cardene SR (Nicardipine); Procardia, Procardia XL, Adalat CC (Nifedipine); Sular (Nisoldipine); Calan, Verelan, Covera-HS (Verapamil)]
Function: Calcium channel blockers (calcium antagonists) inhibit calcium ions from getting into the cell walls of the heart and the muscles surrounding blood vessels, causing them to relax (for a muscle to contract, it needs calcium ions (Ca2+) to cross its' cell membrane).
Common side effects include: Constipation, drowsiness, flushing, headache, nausea, rapid pulse, swelling in the lower legs and feet. Some calcium channel blockers react with grapefruit and foods that contain grapefruit by blocking the liver from properly removing them from the blood - resulting in dangerous concentrations.
Central-acting agents - [Catapres (Clonidine); Tenex (Guanfacine); Methyldopa]
Function: Central-acting agents (central adrenergic inhibitors; central alpha agonists; central agonists) work directly in the brain, blocking signals to speed up heart rate or constrict blood vessels. This class of drug is less commonly prescribed due to strong side effects.
Side effects include: Constipation, depression, dizziness, dry mouth, drowsiness, fatigue, headache, impotence, impaired thinking, and weight gain. Abrupt discontinuation can cause dangerous spikes in blood pressure - especially when taken with a beta-blocker.
Diuretics come in three classes:
Thiazide Diuretics - [Diuril (Chlorothiazide); Hydrochlorothiazide; Zaroxolyn (Metolazone)]
Loop Diuretics - [Bumex (Bumetanide); Edecrin (Ethcrynic acid); Lasix (Furosemide); Demadex (Torsemide)]
Potassium-sparing Diuretics - [Amiloride, Dyrenium (Trimterene); Inspra (Eplerenone); Aldactone (Spironolactone)
Function: Diuretics work by causing the kidneys to excrete sodium and water in the urine - resulting in less fluid in the blood and hence, lower blood pressure.
Side effects include: Increased urination (most common with loop diuretics, for some people this subsides within a few weeks), too much potassium in the blood (with potassium-sparing diuretics), too little potassium in the blood (with thiazide diuretics), breast enlargement in men, increased blood sugar, increased cholesterol, erectile dysfunction (ED, impotence), low blood sodium, rash, gout (joint inflammation), and menstrual irregularities.
Vasodilators - [Hydralzine, Minoxidil]
Function: Vasodilators cause blood vessels to open. Their precise mechanisms are not fully understood. Hydralzine is thought to interfere with calcium ion release in the muscles that surround blood vessels, causing them to relax. The Minoxidil molecule contains a nitric oxide element that may trick blood vessels into opening.
Side effects include: Chest pain, dizziness, flushing, headache, fluid retention, heart palpitations, nausea, sinus congestion, racing pulse, vomiting and excessive hair growth.*
(*Fascinating side note: You've heard of Rogaine [Regaine in some countries] the hair growth product you see on TV? In one of the classic stories of a drug being made for one purpose and its unintended side effect being sold for another, Rogaine is just repackaged Minoxidil. In a similar story, there was another high blood pressure drug that flopped in clinical trials, but it did have some other unexpected and rather interesting side effects... Viagra.)
What's the #1 most dangerous blood pressure drug side effect - the one that you won't find on the label?
Complacency and a false sense of security.
Blood pressure drugs treat the symptoms but they don't treat the deeper causes of the symptoms. For example, if someone isn't managing their stress, the blood pressure medication becomes an "enabler," - merely allowing deeper stress issues to compound. With the underlying cause untreated, the "need" for the drug increases. Wouldn't it make more sense to treat the cause first?
There is indeed a minority of people who, despite trying all the natural ways to lower blood pressure, are still best off taking blood pressure medications. For the rest, the question must be asked, what deeper dangers are the drugs merely masking and at what expense to their whole health picture?
(The drug information in this article is an informative overview only - not a diagnostic tool. Your healthcare needs are unique. Please talk with your physician about the treatment options best suited to your individual needs. Drugs listed are the trademarks of their respective manufacturers.)