Why Your Cardiologist Prescribed a "Diabetes Drug" When You Don't Have Diabetes
If you walked out of a cardiology visit holding a new prescription for empagliflozin (Jardiance) or dapagliflozin (Farxiga), and at the pharmacy someone asked you when you'd been diagnosed with diabetes, you've stumbled into one of the most confusing parts of modern cardiology medication. These drugs were originally approved as diabetes medications. The bottle still says diabetes on it. The prescribing leaflet still talks about blood sugar. Your cardiologist still wants you on it, even though your blood sugar is fine.
There's a real explanation, and it's one of the more interesting stories in cardiology. The short version is that this class of drugs turned out to do something much more useful than lowering blood sugar. They protect the heart and the kidneys, and the protection works whether you have diabetes or not. The label on the bottle hasn't fully caught up to what we now know.
How a Diabetes Drug Stopped Being Just a Diabetes Drug
In the early 2010s, the FDA was making drug companies prove that new diabetes drugs didn't increase the risk of heart attacks. The expectation was that the new drug would be neutral, the safety study would clear it, and the medication would land on the market as one more option for blood sugar control.
That's not what happened. The first big study of empagliflozin in patients with diabetes came back in 2015 with results no one was expecting. The medication didn't just fail to harm the heart; it cut the rate of heart attacks, strokes, and cardiovascular deaths by a meaningful margin. Hospitalizations for heart failure dropped by about a third. The cardiology and diabetes worlds were caught flat-footed. A drug that was supposed to be a sugar control medication turned out to do something much bigger.
Over the next several years, follow-up studies were designed to test whether the same effect showed up in patients without diabetes. Multiple large trials enrolled patients who had heart failure but no diabetes, or kidney disease but no diabetes, and tested whether these drugs still helped. The answer kept coming back yes. The cardiovascular and kidney protection didn't depend on diabetes. The benefit was nearly the same in patients with normal blood sugar as in patients with diabetes. By 2020, this class had become standard care for several heart and kidney conditions, and diabetes was no longer required for the prescription.
What These Drugs Actually Do
The original mechanism, the one the name describes, is in the kidneys. Normally your kidneys filter sugar out of your blood and then reabsorb almost all of it back. These medications block the reabsorption step, so a portion of your sugar ends up in your urine. In someone with high blood sugar, this lowers the sugar. In someone with normal blood sugar, the body adjusts and the sugar stays in the normal range.
The interesting part is that the heart and kidney protection turned out not to come mostly from the sugar effect. These medications do several other things at the same time, and those side benefits are what protect the heart.
They cause the kidneys to release a small amount of extra fluid, which lowers the volume the heart has to pump and reduces strain. The effect is gentler than what diuretic pills do, and it tends to clear fluid from tissues without dramatically dropping blood pressure.
They reduce pressure inside the kidney's filtering units, which is the same reason ACE inhibitors and ARBs protect kidneys. Less filtering pressure means less wear and tear on the kidney over years.
They shift the heart's energy use slightly. The struggling heart seems to do better when it has access to a slightly different fuel mix, and these medications gently push the body in that direction.
There are probably other effects we don't fully understand yet. The bottom line is that the package of changes adds up to less heart failure hospitalization, slower kidney decline, and longer life. The blood sugar effect is along for the ride.
Who Benefits Without Diabetes
A few groups now have clear evidence behind them.
Patients with heart failure where the heart's pumping function is weakened. The studies in this group were big and clean. The medication lowered the rate of dying or being hospitalized for heart failure by about a quarter. The benefit was the same in patients with diabetes as in patients without. If you have a weakened heart, you should be on one of these drugs unless there's a specific reason not to.
Patients with heart failure where the heart's pumping looks normal but the heart isn't relaxing well between beats. This is a common condition, especially in older patients with high blood pressure, and for years we had almost no medications that helped. These drugs were the first to show a clear benefit. Hospitalization rates dropped meaningfully. The improvement isn't as dramatic as in weakened-pump heart failure, but it's the best evidence-based therapy we have for this condition.
Patients with chronic kidney disease, especially with protein leaking into the urine. The kidney protection in this group is substantial. The trials enrolled patients with various levels of kidney function and showed a clear slowing in the rate of decline. For someone already on a maximum dose of an ACE inhibitor or ARB and still losing kidney function, adding one of these medications is one of the most useful interventions we have.
Patients with multiple of the above conditions. Someone with mildly weakened pumping plus mild kidney disease plus a couple of recent heart failure admissions has overlapping reasons to be on the medication.
Patients without any of these conditions but with general cardiovascular risk factors are a more nuanced case. The strongest data is in the conditions above. For routine cardiovascular risk reduction in patients without heart or kidney problems, the case is weaker, and the medication isn't usually first-line.
What to Watch For
Most patients tolerate these drugs well. The side effects are real but usually manageable.
Genital yeast infections show up in about one in twenty patients, more often in women than men. The extra sugar in the urine creates a friendlier environment for yeast in the genital area. Standard antifungal treatment clears it, and good hygiene during the first weeks reduces the chance.
Urinary tract infections happen slightly more often than usual. Drinking enough fluid and not delaying bathroom trips when you need to go are the simple preventions.
Lightheadedness or low blood pressure can show up early, especially in patients already on water pills. The medication has a mild fluid-removing effect on top of any diuretic you're taking, and the combination can drop your pressure too far. The fix is usually a small reduction in your water pill dose for the first couple of weeks. Your prescriber should plan for this when starting you.
A rare but serious problem called diabetic ketoacidosis can happen even when blood sugar is normal. It's much rarer in patients without diabetes than in patients with diabetes, but it's not zero. The signs are unusual nausea, vomiting, abdominal pain, or unusually rapid breathing. If those show up while you're on this medication, especially during a serious illness or right after surgery, you need to be evaluated quickly. Mention to anyone taking care of you that you're on this medication.
Sick day rules apply. If you develop a serious illness with vomiting, dehydration, or an inability to eat, hold the medication until you've recovered. Same goes for a few days before any major surgery. Resume after you're back to your normal intake. If you have a written sick-day plan, follow it; if not, call your prescriber.
A small expected dip in your kidney lab numbers in the first few weeks is normal and not a reason to stop. The kidney filter is adjusting to the medication, and the long-term effect is protection. A bigger jump or a sudden drop needs evaluation.
A rare but very serious infection called Fournier's gangrene, which involves the genital and surrounding skin, has been reported with this class. The absolute risk is very low, but severe pain or swelling in the genital or perineal area, especially with fever, needs urgent attention.
The Cost Question
The honest answer is that these drugs are still expensive. Brand-name dapagliflozin (Farxiga) and empagliflozin (Jardiance) run several hundred dollars a month at retail pharmacy prices. Insurance covers them for the right indication, but copays vary. Manufacturer coupons are available for many patients with commercial insurance and can bring the copay down meaningfully.
For Medicare patients, the negotiated prices that took effect in 2026 have lowered out-of-pocket costs for some patients, though the details depend on the specific plan. Generic dapagliflozin is expected within the next few years. When that lands, the conversation about access will look different.
If cost is a barrier, the manufacturer patient assistance programs are worth exploring. They have income-based eligibility and provide the medication at low or no cost for qualifying patients. My office helps patients apply when needed.
When the medication is being prescribed for heart failure or kidney disease without diabetes, insurance prior authorization sometimes asks for a diabetes diagnosis or an A1c level. The prescription is appropriate without diabetes, and the right diagnosis codes for heart failure or kidney disease usually get the approval through. If your insurance is denying coverage because you don't have diabetes, that's a paperwork issue, not a medical one, and it's worth pushing back through your prescriber.
Common Patient Questions
Will this medication drop my blood sugar too low?
No. These drugs work in a way that doesn't cause low blood sugar in patients without diabetes. The body shuts off the glucose excretion when blood sugar gets close to the normal range. Patients without diabetes don't develop hypoglycemia on these medications.
Why does my creatinine go up after starting?
A small early bump in your kidney number is expected and not harmful. The medication causes the small artery feeding the kidney's filtering unit to constrict slightly, which lowers pressure inside the filter and protects it long-term. Over years, kidney function stays better on the medication than off it. We don't stop the medication for this expected early bump.
Will I lose weight?
Some patients lose a small amount, typically a couple of pounds over the first few months. The weight comes off because of the sugar excreted in urine and a mild fluid removal effect. The weight loss is modest and isn't the reason to be on the medication, but it's a welcome side effect for many people.
Should I check my blood sugar?
Routine sugar checks aren't needed for patients without diabetes on this medication. We typically check basic kidney and electrolyte labs a few weeks after starting, and again at routine follow-up visits. If you develop unusual nausea, vomiting, or abdominal pain on the medication, especially during a serious illness, that's a different scenario where checking ketones in addition to glucose can be useful.
How long do I need to take it?
For most uses, indefinitely. The benefit is steady-state, and stopping the medication appears to reverse some of the gains. For someone with heart failure or kidney disease, this is a long-term medication, similar to a beta blocker or an ACE inhibitor in that respect.
Can I take it with my other heart medications?
Yes. These drugs sit on top of beta blockers, ACE inhibitors, ARBs, Entresto, spironolactone, and water pills without major interactions. The studies tested them as add-on therapy and the benefit held. The one practical adjustment is that your water pill dose may need to come down slightly when you start, to avoid removing too much fluid at once.
Is one drug in this class better than another?
Empagliflozin (Jardiance) and dapagliflozin (Farxiga) are largely interchangeable for heart and kidney conditions. The trial data favors them over the other options in the class. Canagliflozin had a signal years ago about an increased risk of lower-leg amputation in patients with peripheral artery disease, so I tend to avoid it in those patients. Ertugliflozin has weaker outcome data and isn't a typical first choice. The decision between dapagliflozin and empagliflozin often comes down to what your insurance covers and what you can access.
Should I drink less water on this medication?
No, the opposite. Stay well hydrated. The medication has a mild fluid-removing effect, and trying to compound it by drinking less water can leave you dehydrated and lightheaded. Drink water normally, more on hot days, and watch for signs of dehydration on sick days.
When to Get Help Quickly
Go to the emergency department for severe abdominal pain, persistent vomiting, rapid breathing, confusion, or unusual fatigue while on this medication. These can signal a rare but serious chemical imbalance that needs urgent treatment, even if your blood sugar is normal. Tell the team you're on this medication.
Seek urgent evaluation for severe pain, swelling, or redness in the genital or perineal area, especially with fever. Severe infections in this area are rare but need to be caught early.
Call your doctor's office the same day for new lightheadedness or near-fainting, especially in the first few weeks. The fix is usually a small adjustment to your water pill rather than stopping this medication.
Schedule a routine clinic visit four to six weeks after starting the medication. We'll check labs, talk through how you're tolerating it, and confirm that the medication is fitting in well with the rest of your regimen.
A Final Word
When I look at the medications I've started prescribing in the last decade that have actually changed how my patients do, this class is near the top of the list. The benefit is real, the studies are clean, and most patients don't notice anything different day to day. The improvement shows up in the form of fewer hospitalizations, slower kidney decline, and longer life. That's the best kind of medication to be on, even when you can't feel it working.
If you've been prescribed one of these drugs and you're confused about why, ask the question. There's almost always a reason that has nothing to do with diabetes: heart failure of some kind, kidney disease with protein loss, or a combination of conditions where the medication has been shown to help.
Once you understand why you're on it, the rest is straightforward. Take it as prescribed, drink enough water, hold it during sick days and before surgery, watch for the rare but real side effects, and keep your follow-up labs on schedule. The medication has earned its place in modern cardiology, and the patients who take it consistently as part of a larger plan tend to do better than the patients who don't.
References
1. Zinman, Bernard, Christoph Wanner, John M. Lachin, David Fitchett, Erich Bluhmki, Stefan Hantel, Michaela Mattheus, et al. "Empagliflozin, Cardiovascular Outcomes, and Mortality in Type 2 Diabetes." New England Journal of Medicine 373, no. 22 (2015): 2117-2128.
2. McMurray, John J. V., Scott D. Solomon, Silvio E. Inzucchi, Lars Kober, Mikhail N. Kosiborod, Felipe A. Martinez, Piotr Ponikowski, et al. "Dapagliflozin in Patients with Heart Failure and Reduced Ejection Fraction." New England Journal of Medicine 381, no. 21 (2019): 1995-2008.
3. Packer, Milton, Stefan D. Anker, Javed Butler, Gerasimos Filippatos, Stuart J. Pocock, Peter Carson, James Januzzi, et al. "Cardiovascular and Renal Outcomes with Empagliflozin in Heart Failure." New England Journal of Medicine 383, no. 15 (2020): 1413-1424.
4. Anker, Stefan D., Javed Butler, Gerasimos Filippatos, Joao P. Ferreira, Edimar Bocchi, Michael Bohm, Hans-Peter Brunner-La Rocca, et al. "Empagliflozin in Heart Failure with a Preserved Ejection Fraction." New England Journal of Medicine 385, no. 16 (2021): 1451-1461.
5. Solomon, Scott D., John J. V. McMurray, Brian Claggett, Rudolf A. de Boer, David DeMets, Adrian F. Hernandez, Silvio E. Inzucchi, et al. "Dapagliflozin in Heart Failure with Mildly Reduced or Preserved Ejection Fraction." New England Journal of Medicine 387, no. 12 (2022): 1089-1098.
6. Heerspink, Hiddo J. L., Bergur V. Stefansson, Ricardo Correa-Rotter, Glenn M. Chertow, Tom Greene, Fan-Fan Hou, Johannes F. E. Mann, et al. "Dapagliflozin in Patients with Chronic Kidney Disease." New England Journal of Medicine 383, no. 15 (2020): 1436-1446.
7. The EMPA-KIDNEY Collaborative Group, William G. Herrington, Natalie Staplin, Christoph Wanner, Jennifer B. Green, Sibylle J. Hauske, Jennifer R. Emberson, et al. "Empagliflozin in Patients with Chronic Kidney Disease." New England Journal of Medicine 388, no. 2 (2023): 117-127.
8. Heidenreich, Paul A., Biykem Bozkurt, David Aguilar, Larry A. Allen, Joni J. Byun, Monica M. Colvin, Anita Deswal, et al. "2022 AHA/ACC/HFSA Guideline for the Management of Heart Failure." Journal of the American College of Cardiology 79, no. 17 (2022): e263-e421.
9. Kidney Disease: Improving Global Outcomes (KDIGO) Diabetes Work Group. "KDIGO 2022 Clinical Practice Guideline for Diabetes Management in Chronic Kidney Disease." Kidney International 102, no. 5S (2022): S1-S127.
10. Neal, Bruce, Vlado Perkovic, Kenneth W. Mahaffey, Dick de Zeeuw, Greg Fulcher, Ngozi Erondu, Wayne Shaw, et al. "Canagliflozin and Cardiovascular and Renal Events in Type 2 Diabetes." New England Journal of Medicine 377, no. 7 (2017): 644-657.
Published on damianrasch.com. The above information was composed by Dr. Damian Rasch, drawing on individual insight and bolstered by digital research and writing assistance. The information is for educational purposes only and does not constitute medical advice.