Types of Blood Pressure Medications

Diuretics help the body get rid of excess sodium (salt) and water and help control blood pressure. They are often used in combination with additional prescription therapies.

Some noted possible side effects from diuretics:

• Some of these drugs may decrease your body's supply of the mineral potassium. Symptoms such as weakness, leg cramps or being tired may result. Eating foods containing potassium may help prevent significant potassium loss. If your doctor recommends it, you could prevent potassium loss by taking a liquid or tablet that has potassium along with the diuretic. Diuretics such as amiloride (Midamar)*, spironolactone (Aldactone)* or triamterene (Dyrenium)* are called "potassium sparing" agents. They don't cause the body to lose potassium. They might be prescribed alone, but are usually used with another diuretic. Some of these combinations are Aldactazide*, Dyazide*, Maxzide* or Moduretic*.
• Some people suffer from attacks of gout after prolonged treatment with diuretics. This side effect isn't common and can be managed by other treatment.
• People with diabetes may find that diuretic drugs increase their blood sugar level. A change in medication, diet, insulin or oral anti-diabetic dosage corrects this in most cases.
• Impotence may occur.

Beta-blockers reduce the heart rate, the heart's workload and the heart's output of blood, which lowers blood pressure.

Some noted possible side effects of beta-blockers:

• Insomnia
• Cold hands and feet
• Tiredness or depression
• Slow heartbeat
• Symptoms of asthma
• Impotence may also occur
• If you have diabetes and you're taking insulin, have your responses to therapy monitored closely.
• If you have been prescribed beta-blockers, consult your healthcare provider prior to conception if you are considering pregnancy or if there is a chance you could become pregnant. If you discover that you are pregnant consult your healthcare provider as soon as possible to determine the safest medication for you at this time.

Angiotensin is a chemical that causes the arteries to become narrow, especially in the kidneys but also throughout the body. ACE stands for Angiotensin-converting enzyme. ACE inhibitors help the body produce less angiotensin, which helps the blood vessels relax and open up, which, in turn, lowers blood pressure.

Some noted possible side effects of ACE inhibitors:

• Skin rash
• Loss of taste
• Chronic dry, hacking cough
• In rare instances, kidney damage
• Women who are taking ACE inhibitors or ARBs for high blood pressure should not become pregnant while on this class of drugs. If you're taking an ACE inhibitor or an ARB and think you might be pregnant, see your doctor immediately. These drugs have been shown to be dangerous to both mother and baby during pregnancy. They can cause low blood pressure, severe kidney failure, excess potassium and even death of the newborn.

These drugs block the effects of angiotensin, a chemical that causes the arteries to become narrow. Angiotensin needs a receptor- like a chemical "slot" to fit into or bind with- in order to constrict the blood vessel. ARBs block the receptors so the angiotensin fails to constrict the blood vessel. This means blood vessels stay open and blood pressure is reduced.

Some noted possible side effects of Angiotensin II receptor blockers:

• May cause occasional dizziness.
• ARBs should not be used during pregnancy. Medications that act directly on the renin-angiotensin system can cause injury or even death to a developing fetus. When pregnancy is detected, consult your healthcare professional as soon as possible.

This drug prevents calcium from entering the smooth muscle cells of the heart and arteries. When calcium enters these cells, it causes a stronger and harder contraction, so by decreasing the calcium, the hearts' contraction is not as forceful. Calcium channel blockers relax and open up narrowed blood vessels, reduce heart rate and lower blood pressure. 

Some noted possible side effects of calcium channel blockers:

• Palpitations
• Swollen ankles
• Constipation
• Headache
• Dizziness

These drugs reduce the arteries' resistance, relaxing the muscle tone of the vascular walls. 

Some noted possible side effects of alpha blockers:

• Fast heart rate
• Dizziness
• A drop in blood pressure when you stand up

These drugs reduce blood pressure by decreasing the activity of the sympathetic (adrenaline-producing) portion of the involuntary nervous system. Methyldopa is considered a first line antihypertensive during pregnancy because adverse effects are infrequent for the pregnant woman or the developing fetus.

Some noted possible side effects of Alpha-2 Receptor Agonists:

• Methyldopa can cause drowsiness or dizziness

Combined alpha and beta-blockers are used as an IV drip for those patients experiencing a hypertensive crisis. They may be prescribed for outpatient high blood pressure use if the patient is at risk for heart failure.

A noted possible side effect of combined alpha and beta-blockers:

• May cause a drop in blood pressure when you stand up

Central agonists also help decrease the blood vessels' ability to tense up or contract. The central agonists follow a different nerve pathway than the alpha and beta-blockers, but accomplish the same goal of blood pressure reduction.

Some noted possible side effects of central agonists:

• Alpha methyldopa (Aldomet)* may produce a greater drop in blood pressure when you're in an upright position (standing or walking), and it may make you feel weak or faint if the pressure has been lowered too far. This drug may also cause drowsiness or sluggishness, dryness of the mouth, fever or anemia. Male patients may experience impotence. If this side effect persists, your doctor may have to change the drug dosage or use another medication.
• Clonidine (Catapres)*, guanabenz (Wytensin)* or guanfacine (Tenex)* may produce severe dryness of the mouth, constipation or drowsiness. If you're taking any of these drugs, don't stop suddenly because your blood pressure may rise quickly to dangerously high levels.

These medications reduce blood pressure by blocking neurotransmitters in the brain. This blocks the smooth muscles from getting the "message" to constrict. These drugs are rarely used unless other medications don't help.

Some noted possible side effects of peripheral adrenergic inhibitors:

• Reserpine may cause a stuffy nose, diarrhea or heartburn. These effects aren't severe, and no treatment is required other than to change the dosage. If you have nightmares or insomnia or get depressed, tell your doctor; you should stop using the drug.
• Guanadrel (Hylorel)* or guanethidine (Ismelin)* may cause some diarrhea, which may persist in some people. This side effect usually becomes less of a problem if you continue treatment. These drugs reduce blood pressure more when you stand. Consequently, you may get dizzy and lightheaded and feel weak when you get out of bed in the morning or stand up suddenly. If you notice any of these reactions and if they persist for more than a minute or two, contact your doctor. He/she may instruct you to reduce or omit the next dose of the medication.
• When taking guanethidine, don't stand in the hot sun or at a social gathering if you begin to feel faint or weak. These activities cause low blood pressure. Male patients may experience impotence. Contact your doctor if this occurs.

Blood vessel dilators, or vasodilators, can cause the muscle in the walls of the blood vessels (especially the arterioles) to relax, allowing the vessel to dilate (widen). This allows blood to flow through better.

Some noted possible side effects of vasodilators:

• Hydralazine (Apresoline)* may cause headaches, swelling around the eyes, heart palpitations or aches and pains in the joints. Usually none of these symptoms are severe, and most will go away after a few weeks of treatment. This drug isn't usually used by itself.
• Minoxidil (Loniten)* is a potent drug that's usually used only in resistant cases of severe high blood pressure. It may cause fluid retention (marked weight gain) or excessive hair growth.

† Used in severe cases or when kidney failure is present.