Diuretics: All You Need to Know

Many people with high blood pressure find that exercise (see our article on p6) and dietary modifications help control the condition. But if lifestyle measures are ineffective, medications also may be needed. Diuretics (often called water pills) are commonly prescribed as initial drug therapy, and also are used to help manage heart failure. “Diuretics help the body excrete excess water and salt,” says Judith Beizer, PharmD, clinical professor at St. John’s University College of Pharmacy and Health Sciences. “Salt causes water to build up in blood vessels, so flushing it out of the body reduces the amount of fluid flowing through blood vessels. This decreases pressure on the walls of the arteries, and enables the heart to pump more easily.”

Types of Diuretic There are three categories of diuretic: thiazides, loop diuretics and potassium-sparing diuretics.

• Thiazides, such as hydrochlorothiazide (Microzide®) and chlorthalidone (Thalitone®), are typically prescribed first, and are the only diuretics that dilate blood vessels. “Hydrochlorothiazide is often abbreviated as HCTZ or HCT on prescription labels, and may be combined in one tablet with other blood pressure medications,” notes Beizer. Thiazides may not be suitable for diabetics, people with gout, or those with impaired kidney function.
• Loop diuretics include bumetanide (Bumex®), furosemide (Lasix®), and torsemide (Demadex®). These treat heart failure symptoms by increasing the excretion of fluid from the body. Loop diuretics can raise blood sugar, and may exacerbate pancreatitis (see our article on p7). “Research indicates a slightly higher rate of hip and other fractures in patients who take loop diuretics,” Beizer adds. “If you have the bone-thinning disease osteoporosis but need to take a loop diuretic for a condition like heart failure, your bone health will be more closely monitored by your doctor.”
• Potassium-sparing diuretics help the body retain potassium, so they may be prescribed to people with low potassium levels. Potassium-sparing diuretics are not as strong as other types, so people who take them may need a thiazide or loop diuretic too. Options include spironolactone (Aldactone®), triamterene (Dyrenium®), and amiloride (Midamor®). A common combination drug is hydrochlorothiazide plus triamterene (Dyazide®, Maxzide®).

Balancing Electrolytes

Your doctor should regularly check your electrolyte levels if you take diuretics. “Electrolytes are salts—including sodium, potassium and magnesium—that are present in the blood, body tissues, and body fluids,” Beizer explains. “A proper balance of electrolytes is essential for many bodily processes, including heart function, but diuretics can cause an imbalance. This can be a particular problem if you take a thiazide or loop diuretic, as both can cause potassium depletion.” If you take these types of diuretic, it is important to include potassium-rich foods in your diet—examples include spinach, sweet potatoes, white beans, bananas, watermelon, and cantaloupe. A potassium supplement also may be advisable, especially during the summer months when sweating increases potassium loss. A recent large retrospective study (BMJ Open, February) of people taking furosemide found that those who took prescription potassium supplements when daily outdoor temperatures were about 88 degrees Fahrenheit and higher had a 9.3 percent lower risk of death than those not taking potassium. However, you shouldn’t supplement potassium unless your doctor recommends it.

“Abnormal heart rhythms can be a symptom of electrolyte imbalance, so alert your doctor immediately if you experience palpitations, shortness of breath, or chest pain while taking diuretics,” Beizer cautions. “Low potassium levels also can cause leg cramps, so tell your doctor if you are experiencing these.”

Avoiding Medication Interactions

People who take diuretics and also take certain other medications will need to have their potassium levels carefully monitored. Examples include digoxin (Digitek®, Lanoxin®), some antidepressants, other blood pressure drugs, and cyclosporine (Sandimmune®), which is used to help prevent organ rejection after transplantation. People who take the psychiatric drug lithium (Lithobid®) should avoid diuretics.

Diuretic Side Effects

Many people experience nausea and fatigue when they initially start taking diuretics, but these typically ease as your body adjusts to the medication. “Diuretics also may be associated with dizziness and lightheadedness, so try to get into the habit of rising from a seated or prone position slowly, and take a moment to let any dizziness pass before you become active,” Beizer advises. You also may have more frequent headaches, blurred vision, and increased perspiration. Weight loss is common, and thiazides also can increase sun sensitivity, so be extra-careful and apply sunscreen if you’re outdoors on hot, sunny days.

You may need to urinate more frequently several hours after you take your diuretics. You’ll also likely be thirstier than usual, and your mouth may feel dry. “If you don’t have heart failure, drink plenty of fluids to guard against dehydration,” Beizer says. “Signs of dehydration include decreased urine output, and dark-colored urine. You also may want to cut down on alcohol and caffeine, since these are natural diuretics that will increase urination.”

If you have heart failure, you may need to limit your fluid intake. “In this case, chewing sugarless gum or sucking sugar-free hard candy may relieve a dry mouth, while snacking on frozen grapes can help quench thirst,” Beizer says. “Consult your physician about appropriate fluid intake if thirst continues to be an issue.”

The post Diuretics: All You Need to Know appeared first on University Health News.

Read Original Article: Diuretics: All You Need to Know »

Powered by WPeMatico