Medications and Kidney Function: Questions to Ask in Brampton

March is Kidney Health Month in Canada, a good time to think about the two small organs that do an enormous amount of work. Earlier in this series, we looked at how kidney health and blood pressure are connected. This post focuses on a closely related topic that is often overlooked: how your kidneys and your medications affect each other.

Your kidneys filter waste from your blood, and that includes many medications and their by-products. When kidney function is reduced, some medications can build up in the body, increasing the chance of side effects. Other medications can place extra strain on the kidneys themselves. And some medications are specifically chosen to help protect the kidneys.

For people living with high blood pressure, heart disease, diabetes or chronic kidney disease, all three situations can apply at once. Understanding the basics makes it easier to ask the right questions. The pharmacists at Pharmasave BramCentre, 14 - 7910 Hurontario Street in Brampton regularly help patients think through medications in the context of kidney function.

How the kidneys handle medications

After you take a medication, your body absorbs it, distributes it to tissues, and eventually breaks it down and eliminates it. The liver and kidneys are the main organs responsible for clearing medications. Some medications are cleared mostly by the liver; others depend heavily on the kidneys.

When the kidneys are not filtering as well as they used to, medications that depend on them may stay in the body longer and reach higher levels. For some medications, that makes little difference. For others, it can increase the risk of side effects such as dizziness, confusion, low blood sugar, bleeding, or effects on heart rhythm.

This is why prescribers and pharmacists pay attention to kidney function tests, especially the eGFR, when choosing medications and doses.

Kidney function changes over time

Kidney function can change gradually with age, with long-standing high blood pressure or diabetes, or more suddenly during illness or dehydration. A dose that was right five years ago may not be right today. Similarly, kidney function can temporarily drop during a bad bout of vomiting or diarrhea, and recover afterward.

That is one reason regular blood tests matter for people with chronic conditions. If your prescriber orders kidney tests, try to keep those appointments. And if you have had recent results, it can help to let your pharmacist know, especially if they were different from before.

Medications that may need dose changes

Many common medications may need their doses adjusted, or may be avoided, when kidney function is reduced. Examples of medication groups that pharmacists often check include:

• Some diabetes medications
• Some blood thinners, including several direct oral anticoagulants
• Certain antibiotics and antivirals
• Some medications for gout
• Some medications for nerve pain or seizures
• Some heart medications, such as digoxin
• Some stomach acid medications when used long-term

This list is not complete, and it is not a reason to stop anything. It is simply an illustration of why kidney function matters. Your prescriber and pharmacist consider these factors when your prescriptions are written and filled.

Medications that can stress the kidneys

Some medications can affect the kidneys directly, particularly in people who already have reduced kidney function, are older, or are dehydrated:

• Non-steroidal anti-inflammatory drugs (NSAIDs), such as ibuprofen and naproxen, can reduce blood flow to the kidneys. They are a common cause of avoidable kidney problems, especially when taken regularly.
• The combination of an NSAID with certain blood pressure medications and a diuretic has been associated with an increased risk of acute kidney injury. Pharmacists sometimes refer to this as the “triple whammy.”
• Some contrast dyes used in imaging tests can affect the kidneys in people at risk. If you are booked for a scan with contrast, mention any kidney concerns.
• Some herbal and natural products may affect the kidneys or interact with kidney-related medications.

If you have kidney concerns, ask your pharmacist before using any over-the-counter pain reliever regularly. Acetaminophen is often considered for people with kidney disease, but you should still confirm what is right for you and stay within label limits.

Medications that can help protect the kidneys

On the positive side, some medications are used precisely because they can help slow kidney damage in certain people. For example, some blood pressure medications in the ACE inhibitor and angiotensin receptor blocker groups are often chosen for people with diabetes or protein in the urine. Some newer diabetes medications have also been shown to benefit the kidneys and heart in certain patients.

These medications may cause a small, expected change in kidney blood tests when first started, which your prescriber will monitor. If you see a change in your results after starting one, ask your prescriber what it means rather than stopping the medication.

Sick-day planning

When you are ill with vomiting, diarrhea, fever or are unable to drink enough fluids, some medications can increase the risk of kidney problems or other complications. Common examples include certain blood pressure medications, diuretics, some diabetes medications and NSAIDs.

Some healthcare providers give patients written “sick day” guidance that lists which medications to pause temporarily during a short illness and when to restart them. If you take these types of medications and have never discussed this, ask your prescriber or pharmacist whether such a plan is right for you. Do not stop medications on your own without guidance, and seek medical care if you cannot keep fluids down or your symptoms last more than a day or two.

Why older family members need a closer look

Kidney function tends to decline gradually with age, even in people who feel well. An older adult may have normal-looking creatinine on a blood test yet still have reduced filtering capacity, simply because they have less muscle mass. Older adults are also more likely to take several medications, to become dehydrated during hot weather or illness, and to experience side effects such as dizziness or confusion that can lead to falls.

In many Brampton households, adult children or grandchildren help an older relative with appointments and medications. If that describes your family, a few habits are worth building. Keep a copy of your relative’s most recent kidney test results with their medication list. Make sure every new prescriber, including walk-in clinics and specialists, knows about any kidney concerns. Be cautious about sharing over-the-counter pain relievers between family members, since a product that suits a healthy younger adult may not suit a grandparent with reduced kidney function. And if your relative seems newly drowsy, confused or unsteady after starting a medication, mention it to the pharmacist promptly.

Potassium, phosphorus and supplements

People with reduced kidney function may have trouble removing potassium and phosphorus. Certain medications, including some blood pressure medications and some diuretics, can also raise potassium.

This is where some everyday products deserve caution:

• Salt substitutes often contain potassium chloride.
• Some supplements and sports drinks contain potassium or other minerals.
• Herbal products may affect potassium levels or kidney function.
• Magnesium-containing laxatives and antacids may need caution in kidney disease.

Your healthcare team may give you specific guidance on diet and supplements. Always check before adding a new product.

Questions to bring to the pharmacy

If you have chronic kidney disease, or risk factors such as high blood pressure, diabetes or heart disease, consider asking:

1. “Do any of my medications need to be adjusted for my kidney function?”
2. “Which pain relievers are appropriate for me?”
3. “Is it safe for me to use a salt substitute or this supplement?”
4. “What should I do with my medications if I get sick and dehydrated?”
5. “When should my kidney function be checked again?”

A medication review at Pharmasave BramCentre is a structured opportunity to go through all of these together. Bring every medication you take, including vitamins and natural health products, and your most recent lab results if you have them.

Keeping everything organised

Kidney and heart conditions often involve several medications, and doses may change over time based on blood tests. That can make routines confusing. Practical tools include:

• An up-to-date medication list, ideally with the reason for each medication
• Compliance packs that organise doses by day and time
• The prescription refill service so supplies stay steady
• Home delivery when getting to the store is difficult

When a dose changes, ask the pharmacy to help you remove older strengths from your home supply to avoid mix-ups.

For more information about kidney disease and living well with it, the Kidney Foundation of Canada offers patient resources.

Let Pharmasave BramCentre check your medications

Your kidneys and your medications are partners. Keeping them working well together takes a little attention, a few good questions and a pharmacy team that knows your history. If you would like help reviewing your medications for kidney safety, we are here.

Please visit Pharmasave BramCentre at 14 - 7910 Hurontario Street, Brampton, ON L6Y 0P6, or call (905) 497-5177. You can also connect through the contact page or schedule time with a pharmacist through the booking page.

This article provides general educational information about medications and kidney function. Speak with your own prescriber or pharmacist about your individual medications and doses.