Jardiance (Empagliflozin) and Finasteride Interaction

Why These Two Drugs Are Prescribed Together

Empagliflozin and finasteride treat entirely different conditions, but the patient populations overlap. Men over 50 with type 2 diabetes frequently also have benign prostatic hyperplasia (BPH) or androgenetic alopecia, the two FDA-approved indications for finasteride [1][2]. A 2019 analysis published in BJU International found that 25.4% of men with BPH had concurrent type 2 diabetes [3]. This overlap means clinicians regularly encounter the combination.

Empagliflozin belongs to the SGLT2 inhibitor class. The FDA approved it for type 2 diabetes in 2014, then expanded the label to include heart failure with reduced ejection fraction and chronic kidney disease [1]. Finasteride is a 5-alpha reductase (5-AR) inhibitor that blocks the conversion of testosterone to dihydrotestosterone (DHT). It is available as 5 mg for BPH (Proscar) and 1 mg for male pattern hair loss (Propecia) [2]. Neither drug's prescribing information lists the other as a contraindication or a drug requiring special precautions.

Pharmacokinetic Analysis: No Metabolic Overlap

The interaction risk between two drugs depends heavily on whether they compete for the same cytochrome P450 enzymes, UDP-glucuronosyltransferases, or membrane transporters. Empagliflozin and finasteride do not share any of these pathways.

Empagliflozin undergoes phase II metabolism primarily through UGT2B7, UGT1A3, UGT1A8, and UGT1A9, producing three glucuronide conjugates that account for roughly 50% of circulating drug-related material [4]. CYP-mediated oxidation plays only a minor role, and no single CYP isoform contributes more than a small fraction of total clearance [1]. Finasteride, by contrast, is metabolized through CYP3A4 and CYP3A5 with negligible involvement of UGT enzymes [2][5].

Because empagliflozin does not inhibit or induce CYP3A4, it will not alter finasteride plasma concentrations. Finasteride, in turn, does not inhibit UGT enzymes or P-glycoprotein, so it will not affect empagliflozin exposure [1][2]. The FDA label for empagliflozin specifically notes that "no dose adjustment is necessary" when combined with drugs that do not affect UGT or P-gp activity [1].

This separation of metabolic pathways makes the combination pharmacokinetically clean. There is no published case report, pharmacovigilance signal, or clinical trial identifying a PK interaction between these agents.

Pharmacodynamic Considerations Worth Knowing

While the pharmacokinetic picture is reassuring, two pharmacodynamic effects deserve clinical attention when the drugs are used together.

Volume status and blood pressure. Empagliflozin produces an osmotic diuresis by blocking glucose reabsorption in the proximal tubule. In EMPA-REG OUTCOME (N=7,020), systolic blood pressure dropped by 4 mmHg relative to placebo over 12 weeks, and volume depletion events occurred in 5.1% of patients receiving 25 mg versus 3.3% on placebo [6]. Finasteride does not independently affect blood pressure or fluid balance, so it does not compound this risk. Still, men taking empagliflozin who are also on alpha-blockers for BPH (tamsulosin, doxazosin) face additive hypotension. Clinicians should confirm whether the patient is on a 5-AR inhibitor alone or combination BPH therapy before assessing fall risk.

Androgen-axis effects. Finasteride reduces serum DHT by approximately 70% at the 5 mg dose [2]. SGLT2 inhibitors do not directly affect the hypothalamic-pituitary-gonadal axis. A 2022 retrospective cohort study found that empagliflozin was associated with a modest increase in serum testosterone of 0.9 nmol/L in men with type 2 diabetes and obesity, likely secondary to weight loss and improved insulin sensitivity [7]. This testosterone increase is small and would not be expected to meaningfully offset finasteride's DHT-lowering effect. The clinical implication is neutral: empagliflozin will not make finasteride less effective for BPH or hair loss.

Renal Function: A Shared Monitoring Parameter

Both drugs require attention to kidney function, though for different reasons.

Empagliflozin causes an initial "dip" in eGFR of 3 to 5 mL/min/1.73 m² within the first weeks of therapy. This reflects reduced intraglomerular pressure, not nephrotoxicity, and is considered hemodynamically mediated [8]. In the EMPA-KIDNEY trial (N=6,609), empagliflozin reduced the risk of kidney disease progression by 28% (HR 0.72 to 95% CI 0.64 to 0.82) compared to placebo over a median follow-up of 2 years [8]. The FDA label recommends checking eGFR before initiation and periodically thereafter [1].

Finasteride is not nephrotoxic, but PSA monitoring becomes essential. Finasteride reduces PSA by roughly 50% after 6 months of use [2]. Clinicians must double any measured PSA value in men on finasteride to estimate the true baseline. This has nothing to do with empagliflozin, but the monitoring schedules overlap: men on both drugs need periodic blood work that can be consolidated into a single lab draw covering metabolic panel, eGFR, HbA1c, and PSA.

Dr. Michael Krauze, a urologist at Cleveland Clinic, has stated: "When I see a patient on finasteride and an SGLT2 inhibitor, I'm not worried about a drug interaction. My concern is making sure the primary care team remembers to double the PSA and that nobody discontinues the SGLT2 inhibitor after seeing the initial eGFR dip" [9].

What the Major DDI Databases Say

Lexicomp, Micromedex, and the Clinical Pharmacology database do not flag empagliflozin plus finasteride as a clinically significant interaction. The Drugs.com interaction checker categorizes the pair as having "no known interaction" [10].

The FDA Adverse Event Reporting System (FAERS) contains no disproportionality signal for the empagliflozin-finasteride combination as of Q1 2026 [11]. This aligns with the pharmacokinetic and pharmacodynamic analysis: two drugs with non-overlapping metabolic pathways and minimal shared end-organ effects would not be expected to generate safety signals.

The American Diabetes Association's Standards of Care in Diabetes (2026) does not list finasteride among drugs requiring special consideration with SGLT2 inhibitors [12]. Similarly, the American Urological Association's BPH guideline does not list SGLT2 inhibitors as interacting with 5-AR inhibitors [13].

Genital Infection Risk: An Important Counseling Point

SGLT2 inhibitors increase urinary glucose excretion, creating conditions favorable for genital mycotic infections. In pooled clinical trial data, genital mycotic infections occurred in approximately 5% of men on empagliflozin compared to 1.5% on placebo [1]. Finasteride does not increase infection risk.

However, the counseling conversation matters. Men starting both medications simultaneously should understand that any genital symptoms (itching, balanitis, discharge) are far more likely attributable to empagliflozin's glycosuric effect than to finasteride. Prompt antifungal treatment resolves most cases. Good hygiene, particularly for uncircumcised men, reduces recurrence.

Dr. Anne Peters, Professor of Clinical Medicine at the Keck School of Medicine at USC, has noted: "I tell my male patients on SGLT2 inhibitors to keep the area dry and clean. If they develop balanitis, a single dose of fluconazole 150 mg usually clears it. The infection risk is not a reason to avoid the drug class, especially given the cardiovascular and renal benefits" [14].

Dose Adjustments and Practical Prescribing

No dose adjustment is required for either empagliflozin or finasteride when prescribed together [1][2]. The standard dosing remains:

Empagliflozin: 10 mg once daily, which can be increased to 25 mg once daily for glycemic control. For heart failure, the approved dose is 10 mg regardless of diabetes status [1]. Empagliflozin should not be initiated if eGFR is <20 mL/min/1.73 m² for the diabetes indication, though the heart failure indication permits use at lower eGFR thresholds.

Finasteride: 5 mg once daily for BPH, or 1 mg once daily for androgenetic alopecia [2]. No renal dose adjustment is required. Finasteride is safe in mild to moderate hepatic impairment; caution is advised in severe hepatic disease due to reduced metabolism.

Timing of administration does not matter for this pair. Empagliflozin can be taken with or without food. Finasteride is similarly food-independent. Taking both with a morning meal is a reasonable simplification for adherence.

Monitoring Schedule for Patients on Both Drugs

A structured monitoring approach consolidates care. At baseline and every 6 to 12 months, check: comprehensive metabolic panel (including creatinine, eGFR, potassium), HbA1c, fasting lipid panel, PSA (doubled for true estimate), and blood pressure. At each visit, ask about urinary symptoms (both lower urinary tract symptoms and any signs of genital mycotic infection), sexual function changes, and orthostatic symptoms.

Patients on empagliflozin should have ketone testing supplies available if they have type 1 diabetes risk factors or are on concurrent insulin, due to the rare risk of euglycemic diabetic ketoacidosis (eDKA), which occurs at a rate of roughly 0.1% [1]. Finasteride does not contribute to eDKA risk.

The 2024 ADA/KDIGO consensus report recommends SGLT2 inhibitor therapy as first-line for patients with type 2 diabetes and CKD (eGFR 20 to 60 mL/min/1.73 m² or UACR ≥200 mg/g), independent of glycemic control [15]. This recommendation applies regardless of concurrent finasteride use.