Eplerenone Drug Interactions: What to Avoid and What to Tell Your Doctor

Eplerenone has several clinically significant drug interactions that every patient should know before starting treatment — and any time they add a new medication to their routine. Some interactions are contraindicated (meaning you must not combine them), while others require careful monitoring or dose adjustments. Here's a complete guide.

CONTRAINDICATED: Do Not Take These With Eplerenone

The following combinations are contraindicated — meaning they should never be used together with Eplerenone due to serious safety risks:

1. Strong CYP3A4 Inhibitors

Eplerenone is metabolized by the liver enzyme CYP3A4. Strong inhibitors of this enzyme can dramatically increase Eplerenone blood levels — in one study, ketoconazole increased Eplerenone exposure by over 5-fold. This raises the risk of severe side effects including dangerous hyperkalemia and hypotension.

Contraindicated strong CYP3A4 inhibitors include:

Ketoconazole and itraconazole (antifungal medications)

Ritonavir, lopinavir, nelfinavir (HIV antiretrovirals)

Clarithromycin and telithromycin (macrolide antibiotics)

Nefazodone (antidepressant)

If you are prescribed any of these medications while on Eplerenone, contact your prescriber immediately. An alternative may be available for the interacting drug.

2. Potassium Supplements and Potassium-Sparing Agents (Hypertension Indication)

For patients taking Eplerenone specifically for hypertension (high blood pressure), potassium supplements and other potassium-sparing diuretics (like triamterene or amiloride) are contraindicated. Combining these with Eplerenone can cause dangerous hyperkalemia. Even potassium-containing salt substitutes should be avoided.

USE WITH CAUTION: Moderate CYP3A4 Inhibitors

The following moderate CYP3A4 inhibitors require dose adjustment of Eplerenone (maximum 25 mg once daily for post-MI heart failure patients; start with 25 mg for hypertension). They are not absolutely contraindicated but must be managed carefully:

Erythromycin (antibiotic) — increases Eplerenone levels by up to 100%

Verapamil (heart medication) — increases Eplerenone levels by up to 100%

Saquinavir (HIV medication)

Fluconazole (antifungal) — commonly used for yeast infections

Always tell your prescriber or pharmacist before starting a course of fluconazole or erythromycin if you're on Eplerenone. A short-term course may require temporary dose adjustment.

MONITOR CAREFULLY: ACE Inhibitors and ARBs

ACE inhibitors (like lisinopril, enalapril, ramipril) and ARBs (like losartan, valsartan, candesartan) are commonly prescribed alongside Eplerenone in heart failure patients — this is actually guideline-recommended therapy. However, combining them significantly increases the risk of hyperkalemia. Regular potassium monitoring becomes even more important when these are used together.

If you're on both an ACE inhibitor or ARB and Eplerenone, your doctor should be monitoring your potassium more frequently, especially when doses are changed.

MONITOR CAREFULLY: NSAIDs

Nonsteroidal anti-inflammatory drugs (NSAIDs) like ibuprofen (Advil, Motrin), naproxen (Aleve), and others can:

Reduce the antihypertensive effect of Eplerenone

Increase the risk of hyperkalemia, especially in patients with kidney impairment

If you need pain relief while on Eplerenone, discuss with your doctor. Acetaminophen (Tylenol) is generally a safer alternative for most patients.

MONITOR CAREFULLY: Lithium

Lithium toxicity has been reported in patients taking lithium with diuretics or ACE inhibitors. While there is no specific Eplerenone-lithium study, the same principle applies: Eplerenone may affect sodium and fluid balance in ways that alter lithium clearance. If you take lithium (commonly used for bipolar disorder), your doctor should monitor your lithium levels closely when you start or change your Eplerenone dose.

CYP3A4 Inducers: Eplerenone May Be LESS Effective

CYP3A4 inducers speed up the breakdown of Eplerenone, reducing its blood levels and potentially its effectiveness. These include:

Rifampin (antibiotic for tuberculosis) — reduces Eplerenone exposure by about 30%

Carbamazepine, phenytoin, phenobarbital (seizure medications)

St. John's Wort (herbal supplement) — commonly overlooked, but a meaningful CYP3A4 inducer

Food Interaction: Grapefruit Juice

Grapefruit juice inhibits intestinal CYP3A4, increasing Eplerenone exposure by approximately 25%. While not an absolute contraindication, grapefruit juice is best avoided or used minimally and consistently while on Eplerenone. This applies to grapefruit juice specifically — other citrus juices do not have this effect.

Tell Your Doctor or Pharmacist About Everything

Before starting Eplerenone, provide your doctor with a complete list of every medication, supplement, and herbal product you take. Drug interactions are one of the most preventable causes of serious medication side effects. For more about Eplerenone's side effects in general, see our article on Eplerenone side effects. And once your prescription is written, use medfinder to find a pharmacy near you that has it in stock.