10 Medications to Use Carefully in CKD Patients

Because the kidneys are responsible for clearing toxins and processing medications, drugs that are safe for others can become risky for you.

When you have Chronic Kidney Disease (CKD), your kidneys are less able to remove many drugs from the body – so they can build up in the blood and become toxic to the kidneys (and body)

Here are 10 types of medicine that require extra caution, whether they are prescription-strength or available over-the-counter.

1. Why Common Painkillers like NSAIDs (Ibuprofen, Naproxen) Require Extra Monitoring

Non-Steroidal Anti-Inflammatory Drugs (NSAIDs) are the most important medications to use with extreme caution—or avoid entirely.

• Why they are risky: NSAIDs work by blocking certain chemicals that cause pain, but these same chemicals help keep the blood vessels in your kidneys open. When you take an NSAID, those vessels can constrict, suddenly dropping the blood flow to your kidneys.

• Even short-term use can cause Acute Kidney Injury (AKI) for those with existing CKD.

• Safe Alternative: In most cases, Paracetamol (Acetaminophen (Tylenol)) is a safer choice for pain, provided you stay within the recommended daily limits.

2. Metformin

Metformin is the “first line drug” for Type 2 Diabetes, but it is heavily dependent on the kidneys for clearance.

• Why it is risky: If your kidneys aren’t filtering well, Metformin can build up in your blood, leading to a rare but life-threatening condition called Lactic Acidosis.

• The Guidance: Most doctors will lower your dose if your GFR falls below 45 ml/min, and standard practice is to stop it completely if your GFR drops below 30.

3. ACE Inhibitors and ARBs (The “Prils” and “Sartans”)

This is a tricky category because medications like Lisinopril or Losartan are actually prescribed to protect the kidneys.

• The Paradox: While they protect the kidneys long-term, they can cause a sudden drop in kidney function or a dangerous rise in potassium levels when you first start them or increase the dose.

• Caution 1: You must have your blood checked 2 weeks after any dose change.

• Caution 2 (Sick Day Rules): If you are undergoing surgery or have a severe illness where you may be dehydrated, and cannot eat or drink, these must be stopped temporarily,

4. SGLT2 Inhibitors (The “Gliflozins”)

Drugs like Dapagliflozin and Empagliflozin are the “breakthrough” CKD drugs of the mid-2020s.

• The Caution: Much like ACE inhibitors, they are excellent for long-term protection but require careful monitoring. They can cause a slight, expected dip in kidney function initially.

• Sick Day Rules: As with ACE/ARBs, if you are undergoing surgery or have a severe illness where you may be dehydrated, and cannot eat or drink, these must be stopped temporarily,

5. Certain Antibiotics (Aminoglycosides)

If you have a severe infection, and are in hospital, you might be prescribed intravenous (IV) antibiotics like Gentamicin or Tobramycin.

• Why they are risky: These are “nephrotoxic,” meaning they can be directly poisonous to the kidney’s tubule cells.

• What to do: If these are necessary, your medical team should perform “drug monitoring”—taking frequent blood samples to ensure the levels in your body don’t climb too high.

6. Proton Pump Inhibitors (PPIs)

Commonly used for heartburn (e.g., Omeprazole, Lansoprazole), these are often used longer than they should be.

• Why they are risky: Long-term use of PPIs has been linked to Interstitial Nephritis, a type of kidney inflammation.

• What to do: Many patients are now being prescribed H2 blockers (like Famotidine) or lifestyle changes to manage reflux without the kidney risk associated with PPIs.

7. Magnesium-Based Antacids and Laxatives

If you use  Milk of Magnesia or certain “fizzy” antacids, be careful.

• Why they are risky: Kidneys clear excess magnesium. In CKD, magnesium can accumulate to toxic levels, causing muscle weakness, heart rhythm issues, and confusion.

• Top Tip: Always check the “Active Ingredients” label for magnesium or aluminum.

8. Gabapentin and Pregabalin

These are often prescribed for nerve pain or “restless legs,” common symptoms in CKD.

• Why they are risky: These drugs are 100% cleared by the kidneys. If the dose isn’t adjusted downward for your specific kidney stage, the drug will linger in your system, causing extreme sleepiness, dizziness, and an increased risk of falls.

• The Rule: “Start low (dose) and go slow.”

9. Certain Oral Anticoagulants (Blood Thinners)

Newer blood thinners like Apixaban, Dabigatran or Rivaroxaban (which are called DOACs) are convenient because they don’t require the frequent testing that older drugs like Warfarin do.

• The Risk: However, because they are cleared by the kidneys, a sudden drop in kidney function can cause the drug to stay in your blood too long, significantly increasing your bleeding risk.

• Top Tip: Apixaban is the best of this DOAC group for CKD patients. A lower dose may be required in Stages 4-5 CKD.

10. Herbal Supplements (The “Unknowns”)

Many patients assume “natural” means “safe for kidneys,” but the opposite can be true.

• The Risk: Supplements like St. John’s Wort, Echinacea, and even high doses of Vitamin C or Turmeric can interact with CKD medications or contain minerals like potassium and phosphorus that your kidneys can’t handle.

• The Warning: Because supplements aren’t regulated like drugs, they may contain “hidden” ingredients that are toxic in COD patients.

Key Takeaways for Patients

1. The “Sick Day” Rule: If you are vomiting or have severe diarrhoea, or another type of more severe infection, contact your doctor. Some of these “good” drugs (like ACE inhibitors and SGLT2i) should be paused until you are rehydrated.

2. The Pharmacist is Your Ally: Always use the same pharmacy so their computer system can flag interactions.

3. Know Your GFR: Knowing your GFR helps you tell any doctor you visit exactly what your kidneys can handle.

Important Note: Never stop a prescription medication without talking to your doctor first. Often, the benefit of the drug (like controlling blood pressure) outweighs the risk, as long as the dose is correctly adjusted.