When you’re managing type 2 diabetes, taking a medication like SGLT2 inhibitors a class of diabetes medications that lower blood sugar by causing the kidneys to remove excess glucose through urine can feel like a win. These drugs - including canagliflozin, dapagliflozin, empagliflozin, and ertugliflozin - don’t just help control blood sugar. They also cut your risk of heart failure and kidney damage. But there’s a rare, serious side effect you need to know about: Fournier’s gangrene a life-threatening bacterial infection that destroys skin and tissue around the genitals and anus.
It sounds scary. And it is. But here’s the truth: this isn’t common. Out of 10,000 men taking an SGLT2 inhibitor, maybe one will develop this infection over several years. Still, when it happens, it moves fast. And if you don’t act fast, it can kill you. That’s why knowing the warning signs and what to do next isn’t optional - it’s life-saving.
How SGLT2 Inhibitors Might Lead to Fournier’s Gangrene
SGLT2 inhibitors work by making your kidneys dump extra sugar into your urine. That’s great for lowering blood sugar. But that sugar doesn’t just disappear. It stays in your urine, creating a sweet, warm, moist environment right where bacteria love to grow - near the urethra, scrotum, or perineum.
That’s not the whole story. The sugar in your urine doesn’t just feed bacteria. It can also change how your skin and tissues hold up. Studies suggest it may weaken the skin’s natural defenses and cause tiny tears or irritation. Add that to the fact that many people on these drugs also have high blood sugar over time - which already weakens the immune system - and you’ve got a perfect storm.
It’s not just men. While Fournier’s gangrene has historically been seen mostly in men, reports now show about one in three cases occur in women. Anyone with diabetes who takes an SGLT2 inhibitor is at risk. And if you’ve had genital yeast infections before - especially recurring ones - your risk goes up.
Early Warning Signs You Can’t Ignore
Fournier’s gangrene doesn’t start with a rash or a little itch. It starts with pain - sharp, deep, and worsening. Here’s what to watch for:
- Severe pain in the genitals, anus, or inner thighs - worse than a UTI or yeast infection
- Redness or swelling that spreads quickly - not just a patch, but a growing area
- Warmth or heat in the area, like a hot burn
- Dark or purple skin - this means tissue is dying
- Fever or chills, even if your blood sugar is normal
- Foul-smelling discharge from the genital area
- General feeling of being very sick - fatigue, nausea, confusion
These symptoms don’t show up slowly. They can go from mild discomfort to emergency in under 24 hours. If you’re on an SGLT2 inhibitor and you feel any of this - especially pain and redness - don’t wait. Don’t call your doctor tomorrow. Don’t check if it gets better. Go to the ER now.
What to Do If You Suspect Fournier’s Gangrene
Time is everything. Every hour you wait increases your risk of death by about 9%. Here’s exactly what needs to happen:
- Stop taking your SGLT2 inhibitor immediately. Don’t wait for a doctor’s order. If you suspect this infection, you’re not just stopping a drug - you’re stopping a trigger.
- Call 911 or go to the nearest emergency room. Tell them you’re on an SGLT2 inhibitor and you suspect Fournier’s gangrene. Say the words out loud. They need to hear them.
- Expect immediate action. The ER team will likely start you on broad-spectrum antibiotics right away. They’ll also check for tissue death with imaging or a quick exam. If they see signs of infection spreading under the skin, they’ll take you to surgery.
- Surgery is required. No exceptions. The dead tissue must be cut out - often multiple times - to stop the infection. This isn’t optional. It’s survival.
Many people delay because they think it’s just a bad yeast infection or a urinary tract infection. That’s how this kills. Don’t assume. Don’t self-diagnose. If the pain is unlike anything you’ve felt before - and you’re on an SGLT2 inhibitor - treat it like a medical emergency.
Who’s Most at Risk?
Not everyone on these drugs is equally at risk. The data shows some patterns:
- People with HbA1c over 9% - poor long-term blood sugar control doubles the risk
- Those with a history of genital infections - especially recurrent yeast infections
- People with weakened immune systems - from steroids, chemotherapy, HIV, or other conditions
- Men over 50 - though women are also affected
- People with obesity or poor hygiene - though this isn’t always the case
But here’s the thing: even if you don’t fit any of these, you’re not immune. That’s why every patient starting an SGLT2 inhibitor should get a clear warning - not a vague, “watch for infections,” but a specific list of symptoms and what to do.
Why This Isn’t a Reason to Stop Your Medication
Let’s be clear: the benefits of SGLT2 inhibitors still outweigh the risks for most people. These drugs cut heart failure hospitalizations by 30% and slow kidney disease progression. They’ve saved lives. Thousands of them.
Stopping your SGLT2 inhibitor because you’re scared of Fournier’s gangrene is like refusing to drive because you’re afraid of a rare car crash. The risk is real - but it’s small. The danger is in ignoring it, not in using the drug.
The goal isn’t to avoid these medications. It’s to use them safely. That means:
- Talking to your doctor before starting - especially if you’ve had genital infections before
- Knowing the warning signs cold
- Checking your blood sugar regularly
- Keeping the genital area clean and dry
- Reporting any unusual symptoms immediately
What Your Doctor Should Tell You
Doctors aren’t always trained to deliver this warning clearly. Too often, it gets buried under a list of common side effects like urinary tract infections or thirst. But this isn’t a common side effect. It’s a rare, deadly one.
You deserve to hear this straight: “If you develop sudden, severe pain, swelling, or redness in your genitals or around your anus - even if you feel fine otherwise - go to the ER right away. Tell them you’re on an SGLT2 inhibitor. Don’t wait. Don’t call. Go.”
If your doctor doesn’t say this - ask them. Write it down. Put it on your phone. Share it with someone you trust.
What’s Being Done Now?
Regulators know this is serious. The U.S. FDA added a boxed warning to all SGLT2 inhibitors in 2018 - the strongest warning they can give. The European Medicines Agency and the UK’s MHRA did the same. All product labels now list Fournier’s gangrene as a possible side effect.
Pharmacovigilance systems are still tracking new cases. As of 2024, about 1.9 cases occur per 100,000 patient-years. That’s rare - but not negligible. Researchers are now working on tools to predict who’s most at risk, using factors like HbA1c levels, past infections, and immune health.
For now, the best defense is awareness. You don’t need to be afraid. But you do need to be alert.
Can women get Fournier’s gangrene from SGLT2 inhibitors?
Yes. While Fournier’s gangrene was once thought to affect only men, about one-third of reported cases in the EU and UK have occurred in women. Any person taking an SGLT2 inhibitor - regardless of gender - should watch for sudden pain, swelling, or redness in the genital or perineal area.
If I have a yeast infection, should I stop my SGLT2 inhibitor?
Not necessarily. Yeast infections are common with SGLT2 inhibitors and usually respond to antifungal treatment. But if the infection doesn’t improve after 3-5 days, or if you develop pain, swelling, fever, or dark skin - stop the drug and go to the ER. That’s when it may be turning into something more serious.
Are all SGLT2 inhibitors equally risky?
Yes. All four approved SGLT2 inhibitors - canagliflozin, dapagliflozin, empagliflozin, and ertugliflozin - carry this risk. The mechanism (glucose in urine) is the same for all. The FDA and other regulators treat this as a class-wide warning.
How long after starting an SGLT2 inhibitor can Fournier’s gangrene happen?
Cases have been reported as early as a few weeks after starting the drug - and as late as several years. There’s no safe window. That’s why ongoing awareness matters. Even if you’ve been on the drug for a year, you still need to know the signs.
Is there a blood test to check for Fournier’s gangrene?
No. Diagnosis is based on symptoms and physical exam. Imaging like CT scans or ultrasounds can show tissue damage, but they’re not used for early detection. The key is recognizing the symptoms early - pain, swelling, redness, fever - and acting fast. Don’t wait for tests.
Next Steps: What You Should Do Today
- If you’re on an SGLT2 inhibitor, read this again - then share it with someone who helps you manage your health.
- Check your skin. Look for any new redness, swelling, or dark patches around your genitals or anus.
- Know your HbA1c. If it’s above 9%, talk to your doctor about whether you need better control before continuing.
- Write down the warning signs and keep them on your fridge or phone. Set a reminder to review them every 3 months.
- If you’re unsure whether your symptoms are serious - go to the ER. Better safe than sorry. This isn’t something to gamble with.
Diabetes management is about balance. You don’t have to choose between protecting your heart and avoiding rare risks. You just need to know what to watch for - and act without hesitation when it matters most.