Jardiance Side Effects: Rare but Serious Adverse Events Explained

Why "Rare" Does Not Mean "Unimportant"

Empagliflozin's benefit-risk profile is favorable across a wide patient population. The EMPA-REG OUTCOME trial (N=7,020) demonstrated a 38% relative reduction in cardiovascular death versus placebo [1], and EMPEROR-Reduced (N=3,730) showed a 25% reduction in the composite of cardiovascular death or heart-failure hospitalization [2]. Those gains do not erase the obligation to understand where harm concentrates.

Rare adverse events matter for two reasons. First, the absolute patient numbers are large when a drug is prescribed to millions globally. Second, several of the rare events linked to SGLT2 inhibitors are fast-moving and can become fatal within 24 to 48 hours if not recognized.

How Rarity Is Defined in Pharmacovigilance

The Council for International Organizations of Medical Sciences (CIOMS) frequency convention labels an event "rare" when it occurs in 1 in 1,000 to 1 in 10,000 patients and "very rare" at fewer than 1 in 10,000. Several Jardiance adverse events reviewed below fall in these categories based on randomized trial incidence rates; others are identified primarily through post-market spontaneous reporting in FDA's FAERS database.

The Problem of Euglycemic Presentation

Many serious SGLT2 inhibitor adverse events present atypically. Euglycemic DKA, for instance, may occur with blood glucose values below 200 mg/dL, so patients and even clinicians may not initially consider ketoacidosis. That diagnostic delay is where mortality risk accumulates.

Euglycemic Diabetic Ketoacidosis (DKA)

Euglycemic DKA is the most clinically consequential rare event associated with empagliflozin, and the one most likely to be missed at first presentation. Patients develop significant ketosis without the markedly elevated glucose that typically signals DKA, making the diagnosis easy to overlook in an urgent care or emergency setting.

Mechanism

SGLT2 inhibitors reduce renal glucose reabsorption, lowering blood glucose and insulin secretion. The resulting relative glucagon excess, combined with increased free fatty acid oxidation, drives hepatic ketogenesis. Volume contraction from glycosuria and osmotic diuresis amplifies the effect [3]. Low-carbohydrate dieting or prolonged fasting stresses the same pathway, which is why perioperative periods and ketogenic diets are specifically flagged in the Jardiance prescribing information [4].

Incidence and Trial Data

The absolute incidence of DKA in EMPA-REG OUTCOME was low: 0.1% in the empagliflozin arm versus 0.1% in placebo. Post-market data tell a different story. The FDA issued a Drug Safety Communication in May 2015 after reviewing 73 cases of DKA reported to FAERS for the SGLT2 inhibitor class, noting that most cases required hospitalization [5]. A 2019 systematic review published in BMJ Open (pooling 10 randomized controlled trials, N=27,544 participants) found a relative risk of 2.16 (95% CI 1.15 to 4.06) for DKA versus comparators across the SGLT2 inhibitor class [6].

Who Is at Highest Risk

Type 1 diabetes (empagliflozin is not FDA-approved for T1DM), reduced caloric intake or prolonged fasting, heavy alcohol use, and any acute illness that suppresses oral intake all raise risk substantially. Patients undergoing elective surgery are a particular concern.

Clinical Warning Signs

Symptoms include nausea, vomiting, abdominal pain, fatigue, and dyspnea. Blood glucose may read 140 to 200 mg/dL. Diagnosis requires measurement of serum or urine ketones and blood gas confirmation of metabolic acidosis. The Jardiance prescribing information states: "If DKA is suspected, Jardiance should be discontinued and the patient should be assessed and treated promptly" [4].

A practical three-step perioperative protocol used at several academic centers:

1. Discontinue empagliflozin at least 3 days before any elective procedure requiring general anesthesia or a prolonged nil-per-os period.
2. Check serum ketones on the morning of surgery even if blood glucose is normal.
3. Restart only after the patient is eating normally and has no signs of volume depletion.

Fournier Gangrene (Necrotizing Fasciitis of the Perineum)

Fournier gangrene is a rapidly progressive, polymicrobial necrotizing infection of the genitalia and perineum that carries a mortality rate reported between 20% and 40% in the surgical literature. Its association with SGLT2 inhibitors was formally recognized by the FDA in August 2018 [7].

FDA Signal and Case Count

Between March 2013 and May 2019, the FDA identified 55 cases of Fournier gangrene across the SGLT2 inhibitor class (including empagliflozin, canagliflozin, and dapagliflozin) in FAERS. Twelve patients died. During the same timeframe, only 19 cases were identified over a 35-year period among users of other antidiabetic drug classes, suggesting a drug-class signal rather than background diabetic risk alone [7].

Why SGLT2 Inhibitors May Predispose

Persistent glucosuria creates a glucose-rich periurethral and perineal environment. SGLT2 transporters are expressed in the genitourinary mucosa, and local immunosuppression from chronic hyperglycemic tissue may lower the barrier to polymicrobial invasion. The exact mechanism remains under investigation.

Recognizing the Emergency

Any patient on empagliflozin presenting with perineal pain, erythema, swelling, or crepitus requires urgent surgical evaluation. The infection spreads along fascial planes faster than overlying skin changes suggest. Waiting for obvious skin necrosis before consulting surgery is a critical error. The FDA label update mandates that prescribers "advise patients to seek medical attention immediately if they develop pain or tenderness, redness, or swelling in the genital or perineal area, along with fever or malaise" [4].

Severe Urinary Tract Infections, Including Urosepsis

Empagliflozin modestly increases the rate of uncomplicated urinary tract infections (UTIs) in clinical trials: roughly 9% versus 7% for placebo in EMPA-REG OUTCOME. Most of these events are lower-tract infections that resolve with standard antibiotics.

The Urosepsis Problem

The serious concern is upper-tract infections progressing to urosepsis and septic shock. The FDA issued a separate Drug Safety Communication in December 2015 specifically about urosepsis and pyelonephritis across the SGLT2 class, noting cases that required hospitalization and ICU admission [8]. Glucosuria directly enhances bacterial growth in urine, and the same osmotic diuresis that reduces bladder dwell time can paradoxically inoculate the upper urinary tract via retrograde pressure changes.

Risk Stratification

Women, patients with recurrent UTI history, patients with structural urinary tract abnormalities, and immunocompromised individuals face the highest relative risk. Patients who develop a febrile UTI while on empagliflozin should be treated promptly and consideration given to temporary drug discontinuation during the acute illness.

When to Suspect Progression

Flank pain, high fever above 38.5°C (101.3°F), rigors, hypotension, or elevated inflammatory markers in a patient on empagliflozin warrant inpatient evaluation. Blood cultures before antibiotic initiation and renal imaging to rule out abscess or obstruction are appropriate starting points.

Acute Kidney Injury

SGLT2 inhibitors are now first-line agents for chronic kidney disease based on EMPA-KIDNEY (N=6,609), which showed a 28% reduction in the composite of kidney disease progression or cardiovascular death [9]. Yet paradoxically, individual patients may develop acute kidney injury (AKI) on empagliflozin, particularly early in the course of treatment.

Volume Depletion as the Driver

The osmotic diuretic effect of glucosuria can reduce effective circulating volume, especially in patients who are also taking loop diuretics, thiazides, ACE inhibitors, or ARBs. That combination can drop GFR acutely. A 2017 observational study in BMJ (N=72,971 propensity-matched patients across SGLT2 inhibitors versus other antidiabetics) found no overall increase in AKI risk, but noted that patients with volume depletion or intercurrent illness were at elevated risk within the first 30 days of therapy [10].

Sick-Day Rules

Patients should be instructed to hold empagliflozin during any episode of significant dehydration, vomiting, diarrhea, or febrile illness until they can eat and drink normally. This "sick-day rule" is consistent with guidance from the American Diabetes Association Standards of Care [11]. Renal function monitoring is recommended at baseline, after dose changes, and periodically thereafter.

Lower-Limb Amputation Risk

The FDA added a black-box warning for lower-limb amputation to canagliflozin (Invokana) in 2017 following the CANVAS program, which found a risk roughly double that of placebo [12]. Empagliflozin does not carry this black-box warning, and EMPA-REG OUTCOME did not show a statistically significant increase in amputation rates (1.0% empagliflozin versus 1.0% placebo) [1].

Class-Wide Versus Drug-Specific Signal

The FDA label for empagliflozin includes a class-wide precautionary statement about amputation risk, noting that peripheral arterial disease, prior amputation, neuropathy, and diabetic foot ulcers are risk factors that should be assessed before prescribing. Clinicians should ensure patients have adequate foot care and should monitor for new foot symptoms.

Practical Guidance

Patients with known peripheral arterial disease or active foot ulcers should be evaluated by a vascular specialist before starting any SGLT2 inhibitor. Empagliflozin may still be appropriate in these patients after benefit-risk weighing, but the decision should be documented explicitly.

Hypotension and Volume Depletion

Empagliflozin lowers blood pressure modestly, a benefit in most patients with hypertension. In elderly patients, those on antihypertensives, or patients with baseline low blood pressure, this effect can cause symptomatic hypotension, falls, and syncope.

Relevant Trial Data

In EMPA-REG OUTCOME, volume-depletion events (including hypotension, dehydration, and hypovolemia) occurred in 2.4% of the empagliflozin group versus 1.5% of placebo [1]. Patients aged 75 years and older had roughly twice the event rate of younger patients.

Clinical Management

Assess volume status before initiation. Consider dose reductions in diuretic regimens when empagliflozin is added. Patients should be counseled to increase fluid intake during hot weather and physical exertion. Blood pressure should be rechecked within 2 to 4 weeks of initiation in patients at higher risk.

Drug-Induced Genital Mycotic Infections Progressing to Severe Infections

Genital mycotic infections are the most common adverse effect of empagliflozin, occurring in approximately 10% of women and 4% of men in EMPA-REG OUTCOME. While usually mild, recurrent or severe infections can rarely progress to extensive tissue involvement or serve as the entry point for Fournier gangrene.

Management of Recurrent Infections

Patients with more than two mycotic infections per year on empagliflozin should be evaluated for uncontrolled diabetes, immune compromise, and whether the drug benefit outweighs the repeated morbidity. Oral fluconazole 150 mg as a single dose resolves most episodes. Persistent or spreading infections warrant culture and sensitivity testing.

Ketoacidosis in the Perioperative and Sick-Day Context

Beyond elective surgery, empagliflozin-associated DKA has been reported in the context of prolonged vomiting, viral illness with poor oral intake, and post-bariatric surgery states. A case series published in Diabetes Care (2016) described 13 patients who developed euglycemic DKA while on SGLT2 inhibitors in the perioperative period, all with glucose values below 250 mg/dL at presentation [13].

The Society for Endocrinology and the European Society of Endocrinology both recommend holding SGLT2 inhibitors at least 3 days before procedures. The Endocrine Society's Clinical Practice Guideline on inpatient glycemic management reinforces that SGLT2 inhibitors should generally be discontinued on hospital admission [14].

Summary of Rare Serious Events by Frequency and Action Threshold

| Adverse Event | Approximate Frequency | Action Threshold | |---|---|---| | Euglycemic DKA | <0.5% in trials; higher post-market | Nausea, vomiting, anion-gap metabolic acidosis regardless of glucose | | Fournier gangrene | Very rare (<1/10,000) | Any perineal pain, erythema, or swelling with fever: urgent surgical consult | | Urosepsis | Rare (<1/1,000) | Febrile UTI, flank pain, hypotension: hospitalize, blood cultures | | Acute kidney injury | Rare with volume depletion | Creatinine rise >50% from baseline: hold drug, assess volume | | Lower-limb amputation | No significant signal vs. Placebo for empagliflozin | Monitor foot perfusion in PAD patients | | Symptomatic hypotension | ~2.4% in EMPA-REG | Dizziness on standing; reduce diuretics first |

Prescriber and Patient Checklist Before Starting Empagliflozin

Before prescribing empagliflozin, a structured risk assessment reduces the likelihood of the serious events described above.

Screen for:

• eGFR <20 mL/min/1.73 m² (contraindication for glucose lowering)
• Type 1 diabetes or history of recurrent DKA
• Recurrent genital or urinary infections
• Peripheral arterial disease or prior lower-extremity amputation
• Planned surgery or procedure within 4 weeks
• Concomitant loop diuretics or high-dose RAAS blockade with baseline hypotension

Counsel patients to report immediately:

• Abdominal pain, nausea, or vomiting, even with near-normal glucose readings
• Perineal pain, swelling, or redness with or without fever
• Fever with urinary symptoms or flank pain
• Significant dizziness on standing or falls

The Jardiance prescribing information, updated in 2023, remains the authoritative reference for current contraindications, warnings, and dosing adjustments [4].