Diuretics (cont.)

Pharmacy Author:

Annette (Gbemudu) Ogbru, PharmD, MBA

Annette (Gbemudu) Ogbru, PharmD, MBA

Dr. Gbemudu received her B.S. in Biochemistry from Nova Southeastern University, her PharmD degree from University of Maryland, and MBA degree from University of Baltimore. She completed a one year post-doctoral fellowship with Rutgers University and Bristol Myers Squibb.

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Medical Editor:

Jay W. Marks, MD

Jay W. Marks, MD

Jay W. Marks, MD, is a board-certified internist and gastroenterologist. He graduated from Yale University School of Medicine and trained in internal medicine and gastroenterology at UCLA/Cedars-Sinai Medical Center in Los Angeles.

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In this Article

• What are diuretics and how do they work?
• For what conditions are diuretics used?
• Are there differences among diuretics?
• What are side effects of diuretics?
• What are the drug interactions of diuretics?
• Examples of diuretics
• Thiazides diuretics
• Loop diuretics
• Potassium sparing diuretics
• Carbonic anhydrase inhibitors
• Osmotic diuretics
• Nonprescription diuretics

What are side effects of diuretics?

When individuals present with fluid imbalance (depletion) due to diuretics, adverse events such as:

• dry mouth,
• thirst,
• weakness,
• lethargy,
• drowsiness,
• restlessness,
• muscle pains or cramps,
• confusion,
• seizures,
• muscular fatigue,
• hypotension,
• oliguria (decreased or absent production of urine),
• tachycardia, and
• gastrointestinal (GI) disturbances may occur.

Extremely low levels of sodium caused by thiazide diuretics have been associated with death and neurologic damage in elderly patients.

Thiazide diuretics are associated with increase uric acid levels which may cause gout.

What are the drug interactions of diuretics?

Thiazide diuretics given concurrently with antidiabetic drugs [such as oral agents and insulin Apidra, Exubera, Humulin 70-30, Humalog Mix 50-50, Humalog 75-25, Humulin R, Humulin N, Humulin 50-50, Velosulin, Humalog, Lantus, Levemir, Novolog, Novolog Mix 50/50, Novolog Mix 70/30)] causes a decreased blood level of antidiabetic drugs, hence doses of antidiabetic drugs may need to be increased.

Among patients taking digoxin (Lanoxin), low levels of potassium caused by concurrent digoxin and diuretics (thiazide & loop diuretics) may cause weakness, cramps, and irregular heartbeats.

Lithium (Eskalith, Lithobid, Lithonate, Lithotabs) given concurrently with diuretics (thiazides and loop diuretics) may induce lithium toxicity due to decreased renal elimination of lithium. Lithium levels should be monitored to ensure safety.

Potassium-sparing diuretics given with angiotensin converting enzyme (ACE) inhibitors or nonsteroidal anti-inflammatory drugs (NSAIDs) [for example, indomethacin (Indocin)] have been associated with severely elevated levels of potassium (hyperkalemia). Severe hyperkalemia may present as muscle weakness, fatigue and slow heart rate (bradycardia). It is important to monitor potassium blood levels and to have an electrocardiogram performed.

Diuretics are often prescribed with other medications for high blood pressure and heart disease. This may increase the effects of these medications, potentially causing electrolyte abnormalities (such as reduced levels of potassium).