Antihypertensives are a class of drugs used to treat hypertension, or high blood pressure. Sometimes hypertension has no known cause and is called "essential hypertension." "Secondary hypertension" is caused by an underlying condition such as kidney disease, sleep apnea, serotonin syndrome or stress. Medications such as pseudoephedrine and steroids can also cause high blood pressure. When blood pressure cannot be lowered with proper diet and nutrition, antihypertensives are used. Depending on the class of antihypertensives, the side effects can range from mild to severe.
Side Effects of Diuretics
Diuretics are used to lower high blood pressure by helping the body to excrete excess water and sodium. Loop diuretics, thiazide diuretics and potassium sparing diuretics are all used for hypertension. The most common side effect of loop diuretics, such as Lasix, is hypokalemia, or low potassium. According to Drugs.com, other side effects of loop diuretics include dry mouth, weakness, diarrhea and headache. Thiazide diuretics, like Diuril, can cause orthostatic hypotension. This means that upon sitting or standing, the blood pressure drops, causing dizziness or fainting. Drugs.com states that difficulty urinating, gout, and hives are severe side effects and should be addressed immediately. Potassium-sparing diuretics retain the potassium that other diuretics cause the body to excrete. Common side effects of these diuretics include nausea, headache and stomach upset.
Side Effects of ACE Inhibitors
ACE inhibitors -- the short form for angiotensin-converting-enzyme inhibitors -- lower blood pressure by preventing a chemical, angiotensin II, from being secreted and causing blood vessels to constrict. Examples of ACE inhibitors include catopril and lisinopril. According to the Texas Heart Institute, common side effects of ACE inhibitors are diarrhea, headache and joint pain. Fever and chills, trouble breathing or jaundice requires immediate attention.
Side Effects of Beta Blockers
Beta blockers stop adrenaline from stimulating beta receptors. Vasodilating beta blockers cause blood vessels to dilate, which lowers blood pressure. Examples of beta blockers are propanolol, metoprolol and carvedilol. Many people who take beta blockers do not have any side effects. Some side effects may include fatigue, dizziness and weakness. If you take multiple types of hypertensive medications, you face an increased risk of side effects.