High blood pressure is called the silent killer for good reason. Left untreated, it can damage the brain, heart, kidneys and liver, cause heart attacks, and lead to strokes. However, some people are wary about taking blood pressure medication because they fear the possible side effects. Knowing the possible side effects of blood pressure medications allows you to tell a common side effect from one that might be dangerous.
Side Effects of Diuretics
Diuretics, such as hydrochlorothiazide, control high blood pressure by reducing the volume of water in the bloodstream. As a result, their major side effect is an increase in the frequency of urination. However, as they remove water from the body, they also remove potassium, which is necessary to normal cell function. Too little potassium can lead to dizziness and heart problems. If you suspect you have low potassium, see your doctor; blood tests can show the level, and your doctor can work with you to plan how best to add potassium to your diet. Other side effects include upset stomach, muscle cramps and thirst. Serious side effects of diuretics include difficulty breathing or swallowing, gout, and severe rash.
Side Effects of Calcium Channel Blockers
Calcium channel blockers, such as amlodipine and verapamil, slow down the entry of calcium into heart and blood-vessel cells, making them relax and lowering blood pressure. Potential side effects include constipation; diarrhea; swelling of the hands, lower legs, feet and ankles (edema); stomach pain and upset; lightheadedness; tiredness; rashes; and headaches. Less-common side effects include fainting, chest pain, and a pounding, irregular or fast heartbeat. Contact your doctor if you experience these side effects. The action of these medications can be affected by grapefruit juice and alcohol, so be sure to discuss this issue with your doctor.
Side Effects of Alpha Blockers
Alpha blockers, such as doxazosin and tamsulosin, affect the nerve signals that make blood vessels contract; pressure through a contracted vessel is higher than through a relaxed one. Among the side effects of these drugs is their tendency to alter the effect of other medications you may be taking; they may make the medication act more strongly or less so. It's important for the prescribing doctor to be aware of anything else you are taking when considering giving you an alpha blocker. Other side effects include headache, nausea, dizziness (especially after rising from a prone position), rapid heartbeat and a general feeling of weakness.
Side Effects of Beta Blockers
Beta blockers include the drugs propranolol, metoprolol and atenolol. They work by interfering with the action of the hormone epinephrine, or adrenaline, and making the heart beat more slowly. Their common side effects are upset stomach, cold hands, diarrhea or constipation, lightheadedness, headache, and tiredness. Less common are sleeping difficulties, loss of sexual drive and depression. Serious side effects, which should be reported to the doctor immediately, include an irregular or slow heartbeat; swelling of the hands, legs or feet; chest pain and breathing difficulties. Because of their effect on the heart, these drugs pose special risks to people with asthma, diabetes, overactive thyroids or slow heartbeats; if you have any of these conditions, be sure to inform your doctor.
Side Effects of Vasodilators
Vasodilators relax the walls of the blood vessels, improving flow and reducing blood pressure. They include hydralazine and minoxidil. Common side effects of vasodilators include dizziness, upset stomach, headache and increased body hair. If you experience sudden weight gain, fainting, chest pain, fever, rapid heartbeat or fainting while on vasodilators, contact your doctor right away. These drugs can have negative interactions with diuretics, estrogen, progesterone, insulin, corticosteroids and phenytoin. They shouldn't be taken with bisulfates. Women who are pregnant or nursing and people with uremia, heart disease or diabetes should discuss with their doctors the special risks these medications pose.
Side Effects of ACE Inhibitors
This group of drugs works by preventing the secretion of a hormone, angiotensin II, that narrows the blood vessels. Quinapril, ramipril and enalapril are all ACE inhibitors. The side effects of these medications include a dry cough, allergy-like symptoms, lightheadedness, rashes, muscle pain and kidney problems. Angioedema, the swelling of the tongue, lips and throat that may cause breathing difficulty, can occur; although it is rare, it should be treated right away. Women who are pregnant and people who have kidney problems or high potassium levels should not take these medications.
Side Effects of Angiotensin Blockers
Like ACE inhibitors, angiotensin blockers act on the hormone angiotensin II; they include irbesartan and valsartan. Unlike ACE inhibitors, these medications don't produce a dry cough. However, side effects include dry mouth, headache, nausea and pain in the abdomen. These drugs may interact with other medications, including diuretics, lithium and antacids. Be sure the doctor knows about all the medicines you take, both prescription and over-the-counter, to avoid interactions.