Kidney Disease and Your Medications: The Dangerous Combinations Every Mississippi Patient Must Know

What CKD changes about medications

Your kidneys do two things that affect medications. They filter many drugs and their metabolites out of your blood. And they regulate the balance of electrolytes, fluid, and acid base status that many medications depend on or affect.

When kidney function is reduced, three things happen with medications:

• Drugs cleared by the kidneys accumulate. The same dose builds up to higher levels than it would in someone with normal kidneys.
• Some drugs become directly toxic to the kidneys themselves, accelerating decline.
• Some drugs disrupt the electrolyte and fluid balance that CKD patients are less able to compensate for.

OTC products to avoid or use very carefully

NSAIDs (ibuprofen, naproxen, aspirin)

The single most important category to avoid. NSAIDs reduce blood flow to the kidneys, can cause acute kidney injury, and accelerate progression of CKD. Even occasional use is risky in advanced kidney disease. For pain or fever, acetaminophen is generally safer.

Magnesium and aluminum containing antacids

Magnesium accumulates in CKD because the kidneys clear it. Antacids like Maalox and Mylanta should be avoided in moderate to advanced kidney disease.

Phosphate containing laxatives

Fleet phospho soda and similar preparations have caused acute kidney injury and should not be used by CKD patients.

Bismuth subsalicylate (Pepto Bismol)

Contains a salicylate similar to aspirin. Generally avoided in CKD.

High dose vitamin C, vitamin A, and certain herbal products

Some accumulate or can be directly nephrotoxic. Herbal supplements in particular should be reviewed individually.

Prescription medications that need dose adjustment

Many prescription medications need dose reduction in CKD. Your prescriber and pharmacist should be reviewing your kidney function each time a new prescription is added. Common medications requiring adjustment include:

• Several antibiotics, including some that are routinely prescribed without checking, like ciprofloxacin and trimethoprim sulfamethoxazole.
• Metformin. The dose is reduced or held when kidney function drops below a certain level, due to risk of lactic acidosis.
• Many heart and blood pressure medications. The drug class is often appropriate (ACE inhibitors and ARBs are actually protective for many CKD patients), but the dose and the lab monitoring need careful management.
• Gabapentin and pregabalin. Both are renally cleared and accumulate in CKD.
• Some anticoagulants. Dose selection for apixaban, rivaroxaban, and dabigatran depends on kidney function.
• Many opioid medications. Several accumulate dangerously in advanced kidney disease.
• Allopurinol. Standard doses can cause toxicity in CKD; gradual titration is needed.

Contrast dye for imaging studies

If you have CKD and are scheduled for a CT scan with IV contrast, MRI with gadolinium, or any imaging requiring contrast dye, your kidney function should be checked first. In some cases your physician may give IV fluids before and after, hold certain medications temporarily, or choose an alternative imaging approach.

Always remind imaging staff that you have kidney disease, even if it is in your chart. It is information that needs to be active in the conversation, not just buried in the record.

The supplements question

Many supplements are concerning in CKD. Some accumulate. Some are directly nephrotoxic. Some interact with prescription medications. The categories to be careful with include:

• High dose vitamin C (above 500 mg per day) can contribute to oxalate stone formation and may worsen kidney function.
• Vitamin A above the recommended daily amount can accumulate.
• Potassium containing supplements should be avoided. Many CKD patients already have higher potassium than is safe.
• Magnesium supplements should be reviewed with a pharmacist.
• Many herbal supplements, including chaparral, comfrey, ephedra, and certain Chinese herbal preparations, have caused kidney injury.
• Creatine supplementation can affect creatinine and complicate monitoring.

Where pharmacy helps

Free medication therapy management for CKD patients in Hattiesburg, Petal, Laurel, Ellisville, and anywhere across Mississippi. We review every prescription and supplement, identify dosing issues based on your current eGFR, and flag anything that should be reviewed with your nephrologist or primary care physician. Serving Hattiesburg, the Pine Belt, Central Mississippi, and South Mississippi.

When to call a pharmacist

• You have been diagnosed with any stage of CKD.
• You are starting a new prescription medication and are not sure if the dose accounts for your kidney function.
• You are considering an OTC product or supplement.
• You are scheduled for an imaging study requiring contrast dye.
• You see multiple specialists and want a complete medication review.
• Your kidney function has changed recently and your medication list has not been updated.

This article is for general information only and is not a substitute for personalized medical advice. Before starting or changing any medication, including over the counter products and supplements, talk with your pharmacist or physician about your specific situation.