03/12/2013 11:46 am ET Updated May 12, 2013

5 Factors to Consider Before Popping a Pill

Open up your medicine cabinet and you are likely to find a smattering of pill bottles and at least one type of pain medication. Most people don't realize that more than 66 percent of all prescription medications and a large class of over-the-counter pain medications, non-steroidal anti-inflammatory drugs (NSAIDs), are cleared by the kidneys.

You may be wondering what it means for a medication to be "cleared" by the kidneys. Based on their chemical composition, medications remain active in the body for varying lengths of time. While you may typically think of clearance in terms of the retail sales rack, in the medical context, clearance refers to the rate at which your kidneys remove or filter medications from your blood and your body. Kidneys can either degrade or remove medications from your system. If your kidneys aren't working properly, medications can build up. You and your doctor may need to work together to adjust medication dosing and prevent adverse effects, including further kidney damage.

Common prescription and over-the-counter medications may need to be adjusted or avoided if you have kidney damage. Certain cholesterol medications, beta blockers, anti-fungals, antibiotics, antiviral and pain medications are cleared by the kidneys. Heart medications, blood pressure medications, diabetic medications and insulin are also cleared by the kidneys. If you have decreased kidney function, certain types of pain medications, including NSAIDs, are not recommended because they can reduce blood flow to the kidneys. Narcotic pain medications can build up and cause changes in consciousness for patients with chronic kidney disease.

Medications can be lifesaving and life-improving, but they often come with risks and side effects. Many people don't know how well their kidneys are functioning, so they don't realize that they may need to make modifications to their treatment regimen. In honor of National Kidney Month this March, spread the word about the importance of protecting your kidneys when taking medications.

The National Kidney Foundation offers five factors to consider before you reach into the medicine cabinet:

  1. Kidney function. How well are your kidneys working? Are they filtering wastes properly? Have they been damaged? Find out with two simple tests: a urine test for albumin, a protein which can indicate kidney damage, and a blood test for serum creatinine to calculate an eGFR measurement. Your eGFR estimates how well your kidneys are filtering wastes from the blood.
  2. Type of medication. Determine exactly what you're taking. Some medications combine different active ingredients in one pill. Other medications are more often associated with their brand names than their active ingredients. If you have questions, ask your doctor or speak up at the pharmacy.
  3. Dosage. Always read the labels of both prescription and over-the-counter medications because bottles can look similar on the outside, but the strength and recommended dosage can vary. If your kidneys aren't working properly, find out whether you need a different dose or if you should switch to an alternative medication that will work without harming you or your kidneys.
  4. Length of use. How long will you need to take this medication? Is it to treat a chronic condition or to quash an infection? The duration of the medication can factor into whether a medication will damage your kidneys. Long-term use of certain medications, such as NSAIDs, can harm healthy kidneys, even when taken at the recommended dosage.
  5. Interactions. Medications can interact with one another and with foods and herbal supplements. Determine whether there is any potential for negative interactions. If so, discuss alternatives with your doctor to manage concerns and to make sure your medications are working as they should, while preventing damage to the kidneys.

Speak with your clinician and pharmacist to evaluate the risks and benefits of taking a particular medication. Ask questions to see if the types of medication you take need to be adjusted based on your kidney function. As always, learn the facts and weigh the pros and cons based on your individual health needs.

Have a question about your protecting your kidneys and taking medications? Ask in the comments below!

For more by Leslie Spry, M.D., FACP, click here.

For more on personal health, click here.

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