Kerendia Drug Interactions: A Complete Guide

Kerendia (Finerenone) is a powerful medication for protecting your kidneys and heart, but it interacts with several other drugs, supplements, and even certain foods. Some of these interactions are dangerous — one category is completely contraindicated (meaning you absolutely cannot take them together).

This guide covers every major and moderate interaction you should know about, plus what to tell your doctor before starting Kerendia.

How Drug Interactions Work with Kerendia

Kerendia is processed (metabolized) in your liver by an enzyme called CYP3A4. Any medication that blocks or speeds up CYP3A4 will change how much Kerendia stays in your bloodstream:

• CYP3A4 inhibitors slow down the breakdown of Kerendia → more Kerendia in your blood → higher risk of side effects (especially hyperkalemia)
• CYP3A4 inducers speed up the breakdown of Kerendia → less Kerendia in your blood → the medication may not work as well

Additionally, because Kerendia's main side effect is hyperkalemia (high potassium), any medication that also raises potassium levels increases your risk.

Medications That Interact with Kerendia

Contraindicated — Do NOT Take Together

These are strong CYP3A4 inhibitors that are absolutely contraindicated with Kerendia:

• Itraconazole (Sporanox) — antifungal
• Ketoconazole (Nizoral) — antifungal
• Ritonavir (Norvir) — HIV protease inhibitor
• Clarithromycin (Biaxin) — antibiotic
• Nefazodone — antidepressant
• Voriconazole (Vfend) — antifungal
• Saquinavir (Invirase) — HIV protease inhibitor
• Nelfinavir (Viracept) — HIV protease inhibitor
• Tucatinib (Tukysa) — cancer medication

If you're taking any of these, your doctor cannot prescribe Kerendia unless the interacting medication is stopped or switched. There is no safe dose adjustment — the combination is prohibited.

Major Interactions — Avoid if Possible

Strong CYP3A4 inducers significantly reduce Kerendia levels and should be avoided:

• Rifampin (Rifadin) — antibiotic for tuberculosis
• Carbamazepine (Tegretol) — seizure medication
• Phenytoin (Dilantin) — seizure medication
• St. John's Wort — herbal supplement (see supplements section below)

Taking these with Kerendia can make Kerendia ineffective at protecting your kidneys and heart.

Moderate Interactions — Use with Caution

Moderate CYP3A4 inhibitors may increase Kerendia levels and require dose adjustment:

• Erythromycin (E-Mycin, Eryc) — antibiotic
• Diltiazem (Cardizem) — calcium channel blocker for blood pressure/heart
• Verapamil (Calan, Verelan) — calcium channel blocker
• Fluconazole (Diflucan) — antifungal

Your doctor may need to adjust your Kerendia dose if you take any of these.

Potassium-raising medications increase the risk of hyperkalemia when combined with Kerendia:

• ACE inhibitors — Lisinopril (Prinivil, Zestril), Enalapril (Vasotec), Ramipril (Altace), and others
• ARBs (angiotensin receptor blockers) — Losartan (Cozaar), Valsartan (Diovan), Irbesartan (Avapro), and others
• Potassium-sparing diuretics — Spironolactone (Aldactone), Eplerenone (Inspra), Amiloride, Triamterene
• NSAIDs — Ibuprofen (Advil, Motrin), Naproxen (Aleve), Celecoxib (Celebrex) — may also reduce kidney function
• Potassium supplements — any form

Note: ACE inhibitors and ARBs are standard therapy for CKD and diabetes, and many patients take them alongside Kerendia. The combination is not contraindicated, but it does require closer potassium monitoring.

Supplements and OTC Medications to Watch

• St. John's Wort: A strong CYP3A4 inducer. Avoid it — it can make Kerendia much less effective.
• Potassium supplements: Including potassium chloride tablets or liquids. Only take these if your doctor specifically tells you to, and expect more frequent lab monitoring.
• NSAIDs (over-the-counter pain relievers): Ibuprofen (Advil, Motrin) and Naproxen (Aleve) can raise potassium and stress the kidneys. Use Acetaminophen (Tylenol) for pain instead, unless your doctor says otherwise.
• Salt substitutes containing potassium: Products like Nu-Salt and Morton Salt Substitute replace sodium with potassium chloride. Avoid these while taking Kerendia.

Food and Drink Interactions

• Grapefruit and grapefruit juice: Grapefruit inhibits CYP3A4 and can increase Kerendia levels in your blood. Avoid grapefruit and grapefruit juice while taking Kerendia.
• Potassium-containing salt substitutes: As mentioned above, use with caution or avoid.

Otherwise, Kerendia can be taken with or without food, and there are no restrictions on other foods or beverages.

What to Tell Your Doctor

Before starting Kerendia, make sure your doctor knows about:

• Every medication you take — prescription, over-the-counter, and herbal supplements. Don't leave anything out.
• Any antifungal medications — even if they seem unrelated to your kidney or heart condition.
• HIV medications — many protease inhibitors are strong CYP3A4 inhibitors.
• Seizure medications — Carbamazepine and Phenytoin are strong CYP3A4 inducers.
• Any new medications prescribed by other doctors while you're already on Kerendia. Always mention that you take Finerenone (Kerendia).
• Over-the-counter pain relievers you use regularly, especially Ibuprofen or Naproxen.
• Supplements — especially St. John's Wort, potassium, and herbal products.

Keep an updated medication list and bring it to every appointment and pharmacy visit. If a new doctor or dentist prescribes something, tell them you're on Kerendia.

Final Thoughts

Kerendia's drug interactions are well-defined and manageable — as long as you and your healthcare team are aware of them. The biggest things to remember:

1. Never combine Kerendia with strong CYP3A4 inhibitors — this is a hard rule, not a suggestion.
2. Avoid strong CYP3A4 inducers — they'll make the medication ineffective.
3. Watch your potassium — especially if you take ACE inhibitors, ARBs, or potassium supplements.
4. Skip the grapefruit.

For more information on Kerendia, see our guides on side effects, uses and dosage, and how Kerendia works. If you need help finding Kerendia in stock, visit Medfinder.