Ivabradine: what it treats, how to take it, side effects
Last updated September 3, 2026.
Ivabradine (brand name Corlanor) slows the heart rate by acting directly on the heart's natural pacemaker, and it does nothing else: no blood-pressure drop, no bronchospasm, no fatigue spiral. That single-mindedness makes it the add-on for heart-failure patients whose pulse stays fast despite maximal beta-blockers, or who cannot take beta-blockers at all.
What does it treat?
Stable, symptomatic chronic heart failure with reduced ejection fraction (35% or less) in adults who are in sinus rhythm with a resting heart rate of 70 or above despite maximally tolerated beta-blockers, or who cannot take them. It also treats heart failure from dilated cardiomyopathy in children 6 months and older. In the SHIFT trial, it cut heart-failure hospitalizations. It manages the condition; it does not cure it.
How do you take it?
Twice daily with food, at the same times each day, starting at 5 mg twice daily and adjusted after two weeks toward a resting heart rate between 50 and 60 bpm, with 7.5 mg twice daily as the maximum and 2.5 mg for those who get too slow or are on interacting drugs. The target is a pulse number, not a feeling: your prescriber titrates against your actual resting rate, and you can learn to check it yourself. Missed dose: skip it entirely; never double up. Grapefruit is banned. Do not stop without your doctor; it controls, it does not cure.
Side effects to know
- Common: slow heart rate (bradycardia), high blood pressure readings, atrial fibrillation episodes, and the signature oddity: phosphenes, brief luminous flashes or halos in your vision, usually in the first two months and usually harmless.
- Serious: symptomatic bradycardia (fainting, severe dizziness), new atrial fibrillation, and fetal harm, so contraception during treatment matters.
Who should not take it?
Not with acute decompensated heart failure, resting heart rate already below 60 before treatment, very low blood pressure, severe liver impairment, a pacemaker-driven rhythm, or sick sinus syndrome without a pacemaker. Strong CYP3A4 inhibitors and inducers are out, and grapefruit is off the menu. Pregnancy is contraindicated in practice: the label warns of fetal toxicity, and effective contraception is part of the plan for women who could conceive.
When is it an emergency?
Call 911 for fainting, a very slow pulse with confusion or severe breathlessness, a racing irregular heartbeat with chest pain, or signs of stroke. Pymander's escalation routing is built and tested specifically for this class of decision; see the safety architecture working paper.
What a Pymander AI doctor consult looks like
Illustrative example, not a real member's messages.
Common questions
How is ivabradine different from a beta-blocker?
Beta-blockers blunt adrenaline everywhere: heart rate, blood pressure, airways, energy. Ivabradine blocks only the If "funny" channel in the sinus node, the heart's pacemaker, so it slows rate and changes nothing else. That is why it is the add-on for people who have maxed out or cannot tolerate beta-blockers.
Why does my heart rate need to be 50 to 60?
In reduced-ejection-fraction heart failure, a slower resting rate lets the weakened ventricle fill better and work less; the SHIFT trial, which earned the drug its place, showed fewer hospitalizations when rate came down on top of beta-blockers. The 50 to 60 target is the label's titration window, balancing benefit against symptomatic slowness.
What are these flashes of light I am seeing?
Phosphenes: brief luminous phenomena, halos, bright spots, or light trails, reported in a few percent of patients, typically in the first two months. They come from the drug's action on similar channels in the retina, they are almost always harmless and temporary, but report them so your prescriber knows.
Can I use it for a fast heart rate without heart failure?
No. Off-label interest exists for conditions like POTS, but the approval is specific: reduced-ejection-fraction heart failure in sinus rhythm with rate 70-plus despite beta-blockers. A fast pulse from anxiety, thyroid, or deconditioning has different fixes, and using ivabradine there is an off-label specialist decision, not a DIY one.
Why can't I have grapefruit with it?
Ivabradine runs through CYP3A4, and grapefruit blocks that enzyme, spiking drug levels and slowing the heart further than intended. Same reason several antifungals, antibiotics, and HIV drugs are on the interaction list. With a drug titrated to a pulse number, a level-spiking interaction defeats the whole design.
Do I still need my other heart-failure medicines?
Yes. Ivabradine is the fifth wheel, not the chassis: it layers onto the foundational four (beta-blocker, ARNI/ACE/ARB, MRA, SGLT2 inhibitor). It reduces hospitalizations but has not shown the mortality benefit those drugs carry. Stopping foundations because the pulse looks good is exactly the wrong read.