The Four Core Medications

Medical Disclaimer: This content is for educational purposes only and does not constitute medical advice, diagnosis, or treatment. Information is based on current medical literature and clinical guidelines but may not apply to your specific situation. Individual responses vary based on personal medical history and concurrent conditions. Always consult qualified healthcare providers before starting new treatments and for all medical decisions. Never delay seeking medical care based on content you have read.

These articles provide education to enhance your healthcare partnership. All treatment decisions should involve your healthcare team. Use this knowledge to have informed discussions, not replace medical care.

In Brief

For heart failure with a reduced ejection fraction, four classes of medication, taken together, measurably lengthen life and keep people out of the hospital. They are not four drugs for four symptoms. They act through complementary pathways against the biology that drives heart failure forward — the process described in Article 1 — which is why the combination does far more than any single drug, and why leaving one out leaves some of the benefit unrealized. This article explains what each class does, what taking it involves, why doses are adjusted toward the specific targets proven in trials rather than simply added to a list, and why some of them protect the heart silently, doing their most important work without making a person feel different. That last point is the reason these drugs are sometimes stopped even while they are working, and it is useful to understand before a conversation with a care team.

A note on scope: this article is about heart failure with reduced ejection fraction, where these four classes have the strongest evidence. Treatment of the preserved form differs, as Article 2 described.

Why Four Medicines, Not One

To see why four medications are better than one, recall the underlying cycle of heart failure from Article 1. A weakened heart triggers the body’s stress systems — the sympathetic nervous system and the renin-angiotensin-aldosterone system — which briefly prop up blood pressure but, sustained for months and years, tighten blood vessels, retain salt and water, and drive the heart to enlarge and scar. This neurohormonal cycle is a large part of what turns an injured heart into a progressively failing one.[2]

A key advance in modern heart failure treatment was the recognition that this process can be interrupted in more than one way — and that combining medicines that act differently protects the heart far more than any single one. One class calms the renin-angiotensin-aldosterone arm. Another shields the heart from relentless adrenaline-like stimulation. A third blocks the specific hormone that drives fluid retention and scarring. A fourth, discovered almost by accident, protects the heart through several mechanisms still being mapped — and does not sit neatly on the same cycle at all. They are best understood not as four switches on one circuit, but as four complementary forms of protection against the biology that drives the disease forward. Their effects overlap in places, but each adds something the others do not.

That is the logic of what clinicians call guideline-directed medical therapy — the four foundational classes, sometimes called the “four pillars,” that current guidelines recommend for essentially everyone with reduced-ejection-fraction heart failure who can tolerate them.[1] Their combined effect is not small. In a modeling analysis that combined the results of the landmark trials, a person receiving all four classes was estimated to gain roughly six additional years of life at age 55, compared with the older, less complete treatment — and smaller but still meaningful gains even into their 80s.[7] That figure is a projection built from the trials, not a promise to any one person, but the direction and size of the benefit are well supported. Understanding what each pillar does turns that estimate into something a patient can take part in.

The Four Classes: What Each One Does

Renin-angiotensin system inhibition (including ARNI)

The first pillar targets the renin-angiotensin-aldosterone system — the hormonal cascade that constricts blood vessels and drives salt and water retention. Blocking it lightens the load the failing heart pumps against and eases congestion. This class has the longest track record in heart failure: the ACE inhibitors were among the first medicines shown to prolong survival in it, and the ARBs (angiotensin receptor blockers) were developed later as an alternative for people who cannot tolerate an ACE inhibitor.

The most advanced member is the ARNI — an angiotensin receptor-neprilysin inhibitor (the combination drug sacubitril/valsartan). It does two things at once: it blocks the harmful hormonal arm, and it protects the beneficial natriuretic peptides — the heart’s own counter-hormones from Article 1 — from being broken down. Tested head-to-head against the previous gold-standard ACE inhibitor, the ARNI further reduced deaths and hospitalizations, and it is now the preferred option in this class for suitable patients.[3]

One safety point makes the ARNI different from a plain swap: it must never be taken together with an ACE inhibitor, and switching from one to the other requires a gap of at least 36 hours between the last ACE-inhibitor dose and the first ARNI dose. Taking them too close together sharply raises the risk of angioedema, a dangerous swelling of the lips, tongue, or airway. This is a reason the change is made deliberately, under guidance, not treated as interchangeable.

What it involves: blood pressure, kidney function, and potassium are checked when these drugs are started or the dose is changed, because they lower blood pressure and can affect the kidneys.

Beta-blockers

The second pillar shields the heart from the sympathetic nervous system — the “fight-or-flight” drive that floods the failing heart with adrenaline-like signals, forcing it to beat faster and harder than it can sustain. Beta-blockers blunt that drive, slowing the heart and giving it room to recover.

An important detail: only specific beta-blockers are proven to help in heart failure — bisoprolol, carvedilol, and the long-acting form of metoprolol (metoprolol succinate). They are not interchangeable with every drug in the wider beta-blocker family. In its landmark trial, the long-acting metoprolol cut the risk of death by roughly a third — a relative reduction in the trial population, not a guarantee for any one person.[4]

One quirk sets this pillar apart: because slowing an already-struggling heart can briefly reduce its output, beta-blockers are started at a low dose, raised slowly, and usually begun when a person is stable rather than during an acute flare. Mild fatigue or lower energy is common in the early weeks and typically eases as the heart adapts. But a person cannot reliably tell that expected dip apart from something that needs attention — so meaningful worsening, such as increasing breathlessness or swelling, dizziness or fainting, or a very slow heart rate, should be reported to the care team promptly rather than pushed through. Whether to continue, adjust, or pause the dose is a decision for the care team, not one to make alone.

What it involves: heart rate and blood pressure are monitored as the dose is raised, along with how well congestion is controlled.

Mineralocorticoid receptor antagonists (MRAs)

The third pillar blocks aldosterone, a hormone at the end of the renin-angiotensin-aldosterone cascade that promotes salt and water retention and, importantly, drives fibrosis — the scarring that stiffens and weakens heart muscle. The drugs that block it, the mineralocorticoid receptor antagonists (spironolactone and eplerenone), address an arm of the cycle that the first pillar does not fully cover.

In its landmark trial, adding spironolactone to existing therapy reduced deaths by roughly 30 percent — again, a relativereduction, in people with severe heart failure.[5]

What it involves: because these drugs can raise blood potassium and affect the kidneys, potassium and kidney function are checked periodically — a monitoring point, not a reason to avoid them in suitable patients.

SGLT2 inhibitors

The fourth and newest pillar arrived from an unexpected place. The SGLT2 inhibitors (dapagliflozin and empagliflozin) were developed to lower blood sugar in diabetes by making the kidneys excrete glucose — and were found, almost incidentally, to protect the heart. Their precise mechanism in heart failure is still being worked out, but the benefit is well established: in its landmark trial, dapagliflozin reduced worsening heart failure and cardiovascular death, and it did so whether or not the person had diabetes.[6] That a diabetes drug became a cornerstone of heart failure treatment is a clear sign of how deeply the two conditions are linked — a theme Article 11 develops.

What it involves: unlike the other three, these are taken at a single fixed dose rather than titrated, and are generally well tolerated. They make the kidneys pass more glucose and sodium into the urine, which can contribute to volume depletion (too little fluid in the circulation) — especially in people also taking other diuretics — and can raise the risk of genital yeast infections. In rare cases they can trigger a dangerous metabolic state (diabetic ketoacidosis) even when blood sugar is normal, so your care team should give you clear instructions about when to hold the medication temporarily — during acute illness, prolonged fasting, or before a procedure.

Trial results shown are relative reductions in the populations studied, not guarantees for any one person.

Two qualifications matter here. First, not everyone can take all four. Each pillar has specific situations where it is unsuitable — a history of certain allergic reactions, very low blood pressure, reduced kidney function, or high blood potassium among them — so which drugs fit a given person is a clinical judgment, not an automatic default. Second, these four are the foundation, not the whole of treatment. Reduced-ejection-fraction heart failure often also involves diuretics to control fluid (Article 7), correcting iron deficiency, device therapy in selected people (Article 8), treating rhythm problems or blocked arteries, and, in specific circumstances, the combination of hydralazine and isosorbide dinitrate — supported in selected patients, including self-identified Black patients with persistent symptoms despite standard therapy, and some people who cannot use first-line renin-angiotensin system inhibitors.[1] The four pillars are where the strongest, broadest evidence lies; they are not the entire plan.

One common mix-up is worth clearing up here. The water pills (diuretics) that many people think of as their main heart-failure medicine work differently from the four pillars. Diuretics are used mainly to relieve congestion and control fluid symptoms — you can feel them work — but, unlike the four foundational classes, they are not considered the core disease-modifying therapy of heart failure. The four pillars do the opposite: they mostly cannot be felt, yet they slow the disease and prevent major events. Both can be essential; they simply do different jobs.

Why the Combination Beats Any Single Drug

The reason these four are described together, rather than ranked against each other, is that their benefits are largely independent and additive. Each adds protection through a different, though sometimes overlapping, pathway — so each provides something the others do not. There is no single “best” pillar to choose instead of the rest; the point is to have all four working at once.

The numbers are substantial. The comparative modeling analysis estimated that comprehensive four-class therapy lowered the risk of cardiovascular death or heart-failure hospitalization by around 60 percent compared with the older two-drug approach — translating, in the same analysis, into the additional years of life noted earlier.[7] No single pillar comes close to that on its own. This is why guidelines frame the goal as getting a person onto all four classes they can tolerate, ideally without long delays, rather than adding them one at a time over many months.[1] Used together, the four classes affect the disease in a way no single one can.

Getting the Dose Right — and What “Right” Means

Having a medication on the list is a start, but not the whole story. For most of these drugs, the trials proved their benefit at specific target doses, and reaching those doses, when a person can tolerate them, adds to the protection. So good treatment is not only about which drugs are on the chart, but whether each has been brought up as far as it safely can be.

Two things make this less mechanical than it sounds. First, the classes differ: the SGLT2 inhibitors are given at a single fixed dose, while the ARNI, beta-blocker, and MRA are usually started low and stepped up over weeks. Second — and this matters for how a person judges their own care — the goal is the target dose, or the highest dose the person can tolerate, whichever comes first. Blood pressure, heart rate, kidney function, potassium, age, and frailty all set real limits, and many people never reach the full trial dose. That is not failing treatment. Being on the right classes, each pushed as far as is safe for that person, is the goal.

The modern approach reflects this. Rather than perfecting one drug before adding the next over many months, current guidance favors starting all four foundational classes early when feasible, then optimizing doses over the following weeks, with the check-ups and blood tests that make raising doses safe.[1] One trial of intensive, closely monitored optimization after a hospitalization — starting and raising guideline-directed medications quickly, with frequent follow-up — reduced readmissions and death and proved safe, support for this more active approach (though it tested rapid optimization of guideline therapy generally, in the drugs available at the time, rather than the exact four-pillar regimen).[8] The work of adjustment is a shared task between patient and care team.

Why Some of These Drugs Are Stopped Even as They Work

A great deal of what goes wrong in heart failure treatment comes down to one fact: most of these four medications do their most important work silently.

A water pill that relieves breathlessness produces an obvious, felt benefit — you can breathe. But the four pillars mostly do not work that way. They protect the heart muscle, quiet the destructive hormonal cycle, and slow the disease over years — benefits a person cannot feel from one day to the next. A beta-blocker may even make someone feel slightly worse at first. An SGLT2 inhibitor or an MRA rarely announces itself at all. From the inside, taking them can feel like taking nothing.

That silence is exactly why they are so often reduced, skipped, or stopped — by people who see no point in a pill that changes nothing they can perceive, or amid the disruption of another illness, a hospital stay, or a long medication list. But not feeling different is not the same as not working. These drugs are holding the disease in check precisely by preventing the deterioration you would otherwise, eventually, feel. Article 2 showed this directly: when proven heart-failure medications were deliberately withdrawn from people whose hearts had recovered, a large share relapsed within months.[10] The recovery was the treatment working, not the disease going away.

None of this means a person should never stop a medication — sometimes there are good reasons to, and side effects are real and worth raising. It means that stopping or lowering one of these drugs is a decision to make with a care team, weighing the silent protection being given up, rather than a decision to make alone because a pill seems to be doing nothing. If a medication is causing problems, that is a conversation to have, not a reason to quietly abandon proven therapy.

The Gap Between What Works and What People Receive

A hard fact sits behind all of this: having effective treatments is not the same as people receiving them.

In a large registry of outpatients with reduced-ejection-fraction heart failure, fewer than one in four eligible patients were receiving all of the guideline-recommended medication classes available at the time — and only about one percent were simultaneously taking target doses of all of them.[9] More recent data, now that a fourth pillar exists, still show that fewer than one in four eligible patients receive all four classes.[11] These medicines, which can add years of life, are frequently underused, under-dosed, or never started.

The reasons are mostly systemic: clinical inertia, fragmented care and rocky handoffs between hospital and clinic, cost and access barriers, the monitoring and follow-up that dose adjustment demands, competing illnesses, and genuine contraindications. Closing this gap is largely a job for health systems and clinicians, not something patients can fix by trying harder. But being an informed participant helps at the edges a person can influence. Someone who knows they should be on four foundational classes — each brought toward a target or maximally tolerated dose, and each protecting even when it cannot be felt — can ask whether their own regimen is as complete as it safely can be. That single conversation sometimes surfaces a gap that would otherwise go unaddressed.

Questions Worth Bringing to Your Next Visit

Turning this into something usable does not require memorizing pharmacology. A few plain questions do most of the work:

• Which of the four foundational classes am I currently taking?
• Is there a medical reason one of the classes is not right for me?
• Are any of my medications still being adjusted toward a target or maximally tolerated dose?
• What blood tests or blood-pressure checks are needed after a change?
• If a medication was stopped in the past, what was the reason — and is it worth revisiting?

None of these presumes anything is wrong; they simply make the current plan clear.

Clinical Bottom Line

For reduced-ejection-fraction heart failure, four medication classes — renin-angiotensin system inhibition (ideally an ARNI), a proven beta-blocker, a mineralocorticoid receptor antagonist, and an SGLT2 inhibitor — each add a different form of protection against the biology that drives the disease, and together they are estimated to add years of life and prevent hospitalizations far beyond what any single one achieves. Their benefit is greatest when all four are used and each is brought toward its proven dose, or the highest a person can safely tolerate — not merely listed. Most of them work silently, without a felt effect, which is exactly why they are wrongly stopped and why “I feel fine” is not a reason to abandon them. These four are the foundation, though not the whole of treatment: diuretics, device therapy, and other measures play their own roles. Which specific drugs, at which doses, in which order, are individual decisions — made with your care team, around your kidney function, blood pressure, and other conditions — never from an article.

What Comes Next

These four medications change the course of the disease, but they are not the drugs that relieve day-to-day fluid symptoms. Article 7 turns to that other half of treatment: fluid balance, the diuretics (“water pills”) that remove excess fluid, and the daily weight that can warn of fluid building up before breathlessness ever appears.

Key Terms

Guideline-directed medical therapy (GDMT): The set of treatments that clinical guidelines recommend based on strong evidence; for reduced-ejection-fraction heart failure, this centers on the four foundational medication classes described here.

Four pillars: The informal name for the four core medication classes for reduced-ejection-fraction heart failure — RAS inhibition (ideally ARNI), a beta-blocker, an MRA, and an SGLT2 inhibitor.

Renin-angiotensin-aldosterone system (RAAS): A hormonal cascade that raises blood pressure by constricting blood vessels and retaining salt and water; overactive in heart failure and targeted by two of the four pillars.

ACE inhibitor / ARB: Older medication classes that block the renin-angiotensin system. ACE inhibitors were among the first drugs shown to prolong survival in heart failure; ARBs are a later alternative for people who cannot tolerate an ACE inhibitor.

ARNI (angiotensin receptor-neprilysin inhibitor): The combination drug sacubitril/valsartan, which blocks the harmful hormonal arm while protecting the beneficial natriuretic peptides; the preferred option in its class for suitable patients.

Beta-blocker: A medication that shields the heart from sympathetic (adrenaline-like) overstimulation; only specific ones — bisoprolol, carvedilol, metoprolol succinate — are proven in heart failure.

Mineralocorticoid receptor antagonist (MRA): A medication (spironolactone or eplerenone) that blocks aldosterone, reducing fluid retention and the scarring of heart muscle; requires monitoring of potassium and kidney function.

Aldosterone: A hormone that drives salt and water retention and promotes fibrosis (scarring) in the heart.

SGLT2 inhibitor: A medication class (dapagliflozin, empagliflozin) originally developed for diabetes that protects the heart in heart failure, with or without diabetes.

Titration: The process of starting a medication at a low dose and raising it in steps toward the target dose, while monitoring for tolerability.

Target dose: The dose tested and intended in the clinical trials supporting the treatment; reaching it, when tolerated, is generally the goal of titration.

References

1. Heidenreich PA, Bozkurt B, Aguilar D, et al. 2022 AHA/ACC/HFSA Guideline for the Management of Heart Failure: A Report of the American College of Cardiology/American Heart Association Joint Committee on Clinical Practice Guidelines. Circulation. 2022;145:e895–e1032. https://doi.org/10.1161/CIR.0000000000001063
2. Hartupee J, Mann DL. Neurohormonal activation in heart failure with reduced ejection fraction. Nat Rev Cardiol. 2017;14(1):30–38. https://doi.org/10.1038/nrcardio.2016.163
3. McMurray JJV, Packer M, Desai AS, et al. Angiotensin–Neprilysin Inhibition versus Enalapril in Heart Failure (PARADIGM-HF). N Engl J Med. 2014;371(11):993–1004. https://doi.org/10.1056/NEJMoa1409077
4. MERIT-HF Study Group. Effect of metoprolol CR/XL in chronic heart failure: Metoprolol CR/XL Randomised Intervention Trial in Congestive Heart Failure (MERIT-HF). Lancet. 1999;353(9169):2001–2007. https://doi.org/10.1016/S0140-6736(99)04440-2
5. Pitt B, Zannad F, Remme WJ, et al. The Effect of Spironolactone on Morbidity and Mortality in Patients with Severe Heart Failure (RALES). N Engl J Med. 1999;341(10):709–717. https://doi.org/10.1056/NEJM199909023411001
6. McMurray JJV, Solomon SD, Inzucchi SE, et al. Dapagliflozin in Patients with Heart Failure and Reduced Ejection Fraction (DAPA-HF). N Engl J Med. 2019;381(21):1995–2008. https://doi.org/10.1056/NEJMoa1911303
7. Vaduganathan M, Claggett BL, Jhund PS, et al. Estimating lifetime benefits of comprehensive disease-modifying pharmacological therapies in patients with heart failure with reduced ejection fraction: a comparative analysis of three randomised controlled trials. Lancet. 2020;396(10244):121–128. https://doi.org/10.1016/S0140-6736(20)30748-0
8. Mebazaa A, Davison B, Chioncel O, et al. Safety, tolerability and efficacy of up-titration of guideline-directed medical therapies for acute heart failure (STRONG-HF): a multinational, open-label, randomised trial. Lancet. 2022;400(10367):1938–1952. https://doi.org/10.1016/S0140-6736(22)02076-1
9. Greene SJ, Butler J, Albert NM, et al. Medical Therapy for Heart Failure With Reduced Ejection Fraction: The CHAMP-HF Registry. J Am Coll Cardiol. 2018;72(4):351–366. https://doi.org/10.1016/j.jacc.2018.04.070
10. Halliday BP, Wassall R, Lota AS, et al. Withdrawal of pharmacological treatment for heart failure in patients with recovered dilated cardiomyopathy (TRED-HF): an open-label, pilot, randomised trial. Lancet. 2019;393(10166):61–73. https://doi.org/10.1016/S0140-6736(18)32484-X
11. Fonarow GC, Ahmad FS, Ahmad T, et al. HF Stats 2025: Heart Failure Epidemiology and Outcomes Statistics — An Updated 2025 Report from the Heart Failure Society of America. J Card Fail. 2025. https://doi.org/10.1016/j.cardfail.2025.07.007

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