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

Ivabradine (Corlanor) has several significant drug and food interactions that patients and providers need to know about. Some are outright contraindicated — meaning you should never take Ivabradine with certain medications. Others require careful monitoring and possible dose adjustment. This guide covers all the key interactions in plain language.

Why Drug Interactions Matter for Ivabradine

Ivabradine is broken down in the body by an enzyme called CYP3A4 (cytochrome P450 3A4). Drugs or foods that interfere with CYP3A4 can dramatically change how much Ivabradine stays in your blood — either too much (raising the risk of dangerous bradycardia) or too little (reducing its effectiveness). This enzyme-based interaction is the most important category for Ivabradine.

CONTRAINDICATED: Strong CYP3A4 Inhibitors

The following drugs are contraindicated with Ivabradine — meaning they should NEVER be taken together. Strong CYP3A4 inhibitors can increase Ivabradine blood levels 7-8 fold, causing life-threatening bradycardia:

Azole antifungals: Itraconazole (Sporanox), ketoconazole (Nizoral), voriconazole (Vfend), posaconazole (Noxafil), fluconazole

Macrolide antibiotics: Clarithromycin (Biaxin), telithromycin (note: azithromycin/Z-Pak is generally NOT a strong CYP3A4 inhibitor)

HIV protease inhibitors: Ritonavir (Norvir), lopinavir/ritonavir, nelfinavir, saquinavir, indinavir

Nefazodone: An antidepressant that is a potent CYP3A4 inhibitor

Action step: If you are prescribed any of the above drugs while on Ivabradine, alert your prescriber and pharmacist immediately. If you develop a fungal infection while on Ivabradine, topical treatments (creams, ointments) are generally safe alternatives to oral antifungals.

CONTRAINDICATED: Grapefruit and Grapefruit Juice

Grapefruit and grapefruit juice contain compounds (furanocoumarins) that inhibit intestinal CYP3A4, which is responsible for breaking down Ivabradine before it even enters the bloodstream. This interaction can significantly raise Ivabradine levels.

Avoid: Grapefruit, grapefruit juice, and similar citrus (Seville oranges, pomelos, tangelos). Orange juice and lemon juice do NOT interact with Ivabradine and are safe.

AVOID: CYP3A4 Inducers (Reduce Effectiveness)

Some drugs and supplements speed up CYP3A4 activity, which breaks down Ivabradine too quickly and reduces its blood levels, potentially making it less effective:

St. John's Wort: A popular herbal supplement for depression — significantly induces CYP3A4. Tell your doctor if you take this.

Rifampicin (Rifampin): Antibiotic used for tuberculosis and certain other infections. Strong CYP3A4 inducer.

Barbiturates: Phenobarbital and similar medications.

Anticonvulsants: Phenytoin (Dilantin), carbamazepine (Tegretol).

MONITOR CLOSELY: Other Heart Rate–Slowing Medications

These drugs can add to Ivabradine's heart-rate-lowering effect. They're often prescribed alongside Ivabradine, but your heart rate needs to be monitored carefully:

Beta-blockers (metoprolol, carvedilol, bisoprolol): Most HFrEF patients take a beta-blocker alongside Ivabradine. The combination is guideline-directed and generally safe, but heart rate should be monitored to avoid excessive bradycardia.

Digoxin: Sometimes co-prescribed in HF. Can additiviely slow heart rate with Ivabradine. Monitor heart rate and digoxin levels.

Amiodarone: Antiarrhythmic that slows heart rate. Use with caution and monitor heart rate closely.

Non-dihydropyridine calcium channel blockers (verapamil, diltiazem): Both slow heart rate AND inhibit CYP3A4. These drugs are generally avoided in HFrEF anyway due to negative inotropic effects, but if used, they add to Ivabradine's heart rate and drug-level effects.

What to Tell Your Doctor and Pharmacist

Before starting Ivabradine, tell your prescriber about:

All prescription medications, including those for heart conditions, infections, HIV, seizures, depression

All over-the-counter supplements, including herbal products like St. John's Wort

Any history of atrial fibrillation, sick sinus syndrome, or heart block

Pregnancy or plans to become pregnant

Liver or kidney disease

While on Ivabradine, always check with your pharmacist or doctor before starting any new medication — prescription or over-the-counter. Your pharmacist can quickly check for interactions using professional drug interaction databases.

The Bottom Line

Ivabradine's most important drug interactions involve CYP3A4 — the enzyme that metabolizes it. Strong inhibitors are contraindicated, and grapefruit juice must be avoided. When combined with other heart-rate-slowing drugs, close monitoring is essential. For more on what symptoms to watch for, see Ivabradine Side Effects: What to Expect and When to Call Your Doctor.