Canagliflozin (Invokana): How It Works, Doses, Benefits, and Risks

Canagliflozin, sold under the brand name Invokana, is an oral SGLT2 (sodium-glucose cotransporter-2) inhibitor approved by the FDA for adults with type 2 diabetes. Combination tablets that pair canagliflozin with metformin are sold as Invokamet (immediate release) and Invokamet XR (extended release). Canagliflozin is not the same drug as empagliflozin (Jardiance) or dapagliflozin (Farxiga), even though all three belong to the same SGLT2 inhibitor class and share a similar glucose-lowering mechanism.

The direct answer: Canagliflozin lowers blood sugar by making the kidneys excrete glucose in urine rather than reabsorbing it, and this same mechanism produces measurable reductions in cardiovascular events and kidney disease progression in adults with type 2 diabetes who already have vascular or kidney disease. That cardio-renal protection, not superior glucose control, is the main reason a clinician chooses canagliflozin over an older oral agent. The tradeoff is a class-associated infection and volume-depletion profile, plus a lower-limb amputation signal that was more pronounced with canagliflozin in its pivotal trial program than has been reported for some other SGLT2 inhibitors, which is why vascular and foot risk factors materially affect who is a good candidate.

What canagliflozin is and how it works

The proximal tubule of the kidney normally reabsorbs the large majority of filtered glucose back into the bloodstream through the SGLT2 transporter. Canagliflozin blocks that transporter, so a substantial amount of glucose that would normally be reclaimed is instead excreted in urine. This lowers blood glucose independent of insulin secretion or insulin sensitivity, which is why canagliflozin can be added to almost any other diabetes medication, including metformin, sulfonylureas, pioglitazone, DPP-4 inhibitors, GLP-1 receptor agonists, and insulin.

The osmotic diuresis that accompanies glucose excretion also produces modest reductions in blood pressure and body weight, effects that are consistent across the SGLT2 inhibitor class and are described in FDA labeling and in the drug class comparative literature (Tsapas et al., comparative effectiveness of individual SGLT2 inhibitors, 2025).

What canagliflozin is approved for

The FDA-approved indications for Invokana are:

1. Improving glycemic control in adults with type 2 diabetes, as an adjunct to diet and exercise.
2. Reducing the risk of major adverse cardiovascular events in adults with type 2 diabetes and established cardiovascular disease.
3. Reducing the risk of end-stage kidney disease, doubling of serum creatinine, cardiovascular death, and heart failure hospitalization in adults with type 2 diabetes and diabetic nephropathy with albuminuria above 300 mg/day (added to the label in 2019).

Canagliflozin is not FDA-approved for type 1 diabetes. It is not recommended for glycemic control once estimated glomerular filtration rate (eGFR) falls below 30 mL/min/1.73 m², though the kidney-protection indication permits continued use at lower eGFR thresholds under specialist guidance. Exact eGFR cutoffs and dose thresholds should be confirmed against the current FDA prescribing information (available through the FDA's Drugs@FDA database, https://www.accessdata.fda.gov/scripts/cder/daf/) rather than assumed from memory, because labeling has been updated more than once since initial approval.

Dosing, in general terms

The typical starting dose is 100 mg once daily, taken before the first meal of the day. If a patient tolerates 100 mg and needs additional glycemic control, the dose may be increased to 300 mg once daily. Dose selection and any increase should be individualized by the prescribing clinician based on kidney function, blood pressure, volume status, and concurrent medications; this article does not provide individualized dosing instructions. Patients with reduced kidney function generally should not use the 300 mg dose, and canagliflozin is typically stopped for glycemic purposes once eGFR falls into the range specified in current labeling. Severe hepatic impairment is a situation where canagliflozin use has not been well studied.

What the glucose-lowering evidence shows

Randomized trials in the canagliflozin development program compared it with placebo, with glipizide (a sulfonylurea), and with sitagliptin (a DPP-4 inhibitor). Reported findings, consistent with what has been publicly described in the diabetes literature, include:

• HbA1c reductions of roughly 0.8 to 1.0 percentage points versus placebo at 26 weeks, varying by dose.
• In a head-to-head trial against glipizide, canagliflozin produced similar glucose-lowering but substantially less hypoglycemia and weight loss instead of weight gain.
• In a head-to-head trial against sitagliptin, canagliflozin produced somewhat greater HbA1c reduction and more weight loss.

These are well-documented trial results from the canagliflozin approval program, but the specific confidence intervals and exact percentage figures should be checked against the original published trials before being used in clinical or patient-facing materials, since this draft could not independently verify every numeric citation inherited from prior source material.

Cardiovascular outcomes: the CANVAS Program

The CANVAS Program (two pooled trials, published in the New England Journal of Medicine in 2017) is the dedicated cardiovascular outcomes trial for canagliflozin. It enrolled adults with type 2 diabetes at elevated cardiovascular risk and found a reduction in major adverse cardiovascular events (cardiovascular death, nonfatal MI, nonfatal stroke) compared with placebo, along with a reduction in heart failure hospitalization. The same program also reported a roughly doubled risk of lower-limb amputation, mostly at the toe or metatarsal level, which led the FDA to add a boxed warning and to instruct prescribers to evaluate patients for peripheral artery disease and foot ulcer history before starting the drug.

A broader review of SGLT2 inhibitor benefits and harms across trials situates this amputation finding as more prominent in canagliflozin's own trial program than in some other SGLT2 inhibitor outcome trials, though comparing drugs across separate trials with different populations has real limits (Zheng et al., benefits and harms of SGLT2 inhibitors, systematic review and meta-analysis, 2016). Whether the amputation signal reflects a true canagliflozin-specific effect, a chance finding, or differences in the populations enrolled remains debated, and clinicians should not assume it generalizes uniformly to every SGLT2 inhibitor.

Kidney outcomes: the CREDENCE trial

CREDENCE was the first dedicated kidney-outcomes trial for an SGLT2 inhibitor and enrolled adults with type 2 diabetes, reduced eGFR, and substantial albuminuria who were already on renin-angiotensin-system blockade. It was stopped early because canagliflozin crossed a pre-specified efficacy boundary for reducing a composite of end-stage kidney disease, doubling of serum creatinine, and renal or cardiovascular death. This trial is the primary basis for the 2019 label expansion and for guideline bodies, including KDIGO, recommending SGLT2 inhibitors with demonstrated kidney benefit as add-on therapy in type 2 diabetes with chronic kidney disease, independent of glycemic control.

A separate review of canagliflozin's cardiovascular and renal risk-reduction profile provides additional context on how these outcome benefits fit into overall cardiovascular risk management in type 2 diabetes (Scheen, clinical potential of canagliflozin in cardiovascular risk reduction, 2018).

Side effects and safety signals

• Genital mycotic (yeast) infections occur more often than with placebo, reflecting glucose in the urine; these are usually manageable with standard antifungal treatment, though recurrence sometimes prompts stopping the drug.
• Volume depletion (dizziness, orthostatic symptoms) can occur, particularly in older adults, people on loop diuretics, or anyone with reduced fluid intake.
• Diabetic ketoacidosis (DKA), including euglycemic DKA where blood glucose looks near normal, is a rare but serious risk across the SGLT2 inhibitor class. Prolonged fasting, very low-carbohydrate diets, alcohol excess, acute illness, and surgery raise this risk. Many institutions recommend holding canagliflozin roughly three days before elective surgery, but the exact interval should follow the prescribing surgeon or anesthesiologist's protocol.
• Lower-limb amputation risk was elevated in the CANVAS Program, as described above. Patients with active foot ulcers, severe peripheral artery disease, or prior amputation are generally considered poor candidates for canagliflozin specifically.
• Bone fracture and bone density signals were reported in canagliflozin trial data; the clinical significance for long-term fracture risk in a general type 2 diabetes population is not fully settled and warrants individualized discussion for patients with osteoporosis or high fracture risk.
• Hyperkalemia is a possibility when canagliflozin is combined with potassium-sparing drugs or used in advanced kidney disease.

How canagliflozin compares with other diabetes drugs

Versus metformin. Metformin remains first-line therapy for most adults with type 2 diabetes because of its long safety record, low cost, and modest weight benefit. Metformin does not have the dedicated cardiovascular or renal outcome trial evidence that canagliflozin has. Canagliflozin is typically added on top of metformin rather than used to replace it, especially in patients with cardiovascular or kidney disease.

Versus glipizide (a sulfonylurea). Sulfonylureas stimulate insulin release regardless of glucose level, which causes more hypoglycemia than SGLT2 inhibitors and tends to promote weight gain rather than weight loss. Canagliflozin has a materially lower hypoglycemia rate in head-to-head data and no dedicated trial evidence exists showing sulfonylureas reduce cardiovascular events the way canagliflozin has demonstrated. Sulfonylureas remain far less expensive, which matters when cost is the deciding factor.

Versus pioglitazone. Pioglitazone improves insulin sensitivity but causes fluid retention and is contraindicated in more advanced heart failure. Canagliflozin's diuretic and weight-reducing effects make it generally preferable in patients with heart failure or obesity, while pioglitazone avoids the genital infection and amputation risks associated with SGLT2 inhibition.

Versus empagliflozin (Jardiance). Both drugs are SGLT2 inhibitors with cardiovascular and kidney outcome trial evidence, but from separate trials with different populations and endpoints. Empagliflozin's outcome trials did not report the same magnitude of amputation signal seen in canagliflozin's CANVAS Program, and empagliflozin's label does not carry the same boxed warning. A later kidney outcomes trial for empagliflozin also extended kidney-protective evidence to a broader population that included some non-diabetic chronic kidney disease. For patients with peripheral vascular disease or prior foot problems, many clinicians favor empagliflozin or dapagliflozin over canagliflozin on the basis of that safety difference. For patients without those risk factors, the two drugs are often considered broadly comparable at a class level, with formulary coverage and cost frequently deciding the choice (Tsapas et al., comparative effectiveness of individual SGLT2 inhibitors, 2025).

Who is, and is not, a reasonable candidate

Canagliflozin is often considered for adults with type 2 diabetes who also have established atherosclerotic cardiovascular disease, heart failure, diabetic kidney disease with significant albuminuria, or a need for weight management support alongside glucose control.

Canagliflozin is generally avoided or used with extra caution in people with type 1 diabetes (not approved, high DKA risk), advanced kidney impairment below the labeled threshold for glycemic use, active foot ulcers or severe peripheral artery disease, recurrent treatment-resistant genital infections, or a personal history of SGLT2 inhibitor-associated DKA.

This is general information, not an individualized recommendation. Whether canagliflozin is appropriate for a specific patient depends on kidney function, vascular exam findings, other medications, and treatment goals that only a treating clinician can weigh.

A decision framework: canagliflozin or a different agent?

This is not a substitute for a clinical evaluation. It organizes the tradeoffs a prescriber and patient typically need to weigh when canagliflozin is on the table as an add-on to metformin or diet and exercise.

The throughline: canagliflozin earns its place in a regimen mainly through cardio-renal risk reduction, not superior HbA1c lowering. The decision usually turns on whether the patient's vascular and kidney risk profile matches the population in which that benefit was demonstrated, and whether foot or peripheral vascular risk factors argue for a different SGLT2 inhibitor instead.

Monitoring while on canagliflozin

Before starting, clinicians typically check kidney function (eGFR), urine albumin-to-creatinine ratio, blood pressure, and perform a foot and lower-extremity vascular exam. A follow-up kidney function check within the first few weeks helps distinguish an expected, usually transient early drop in eGFR from a concerning decline. During ongoing treatment, HbA1c is typically checked every three to six months, annual foot exams are standard for anyone with diabetes, and electrolytes (particularly potassium) warrant periodic review in patients also taking ACE inhibitors, ARBs, or potassium-sparing diuretics. Patients should be told to hold the medication during significant illness, prolonged fasting, or before major surgery, and to seek urgent care for symptoms of DKA (nausea, vomiting, abdominal pain, unusual fatigue, or rapid breathing) even if a home glucose reading looks normal, since euglycemic DKA can occur.

What is established, what is plausible, and what remains uncertain

Established: Canagliflozin lowers blood glucose through urinary glucose excretion, independent of insulin. It has FDA-approved indications for glycemic control, cardiovascular risk reduction in patients with established cardiovascular disease, and slowing of diabetic kidney disease progression in patients with significant albuminuria, based on dedicated outcome trials (CANVAS Program and CREDENCE). Genital mycotic infections and volume depletion are recognized, mechanism-related side effects. A boxed warning for lower-limb amputation risk exists based on the CANVAS Program findings.

Plausible but not fully settled: Whether the amputation signal is a canagliflozin-specific effect versus a broader class effect that happened to appear more strongly in one trial population is still debated in the literature. The long-term fracture and bone density implications of chronic use in a general type 2 diabetes population are not conclusively established.

Not established from the evidence available here: Precise numeric comparisons across different SGLT2 inhibitors' individual outcome trials should be treated cautiously, since those trials enrolled different populations with different follow-up periods; a formal head-to-head trial answering "which SGLT2 inhibitor is safest for amputation risk" does not exist. Readers and clinicians relying on specific effect-size numbers from any single source should verify them against the original trial publications before using them in a treatment decision.

Common questions

References

• Tsapas A, et al. Comparative Effectiveness of Individual Sodium-Glucose Cotransporter 2 Inhibitors. 2025. https://pubmed.ncbi.nlm.nih.gov/39836397/
• Scheen AJ. Clinical potential of canagliflozin in cardiovascular risk reduction in patients with type 2 diabetes. 2018. https://pubmed.ncbi.nlm.nih.gov/30573964/
• Zheng SL, et al. Benefits and Harms of Sodium-Glucose Co-Transporter 2 Inhibitors in Patients with Type 2 Diabetes: A Systematic Review and Meta-Analysis. 2016. https://pubmed.ncbi.nlm.nih.gov/27835680/
• FDA Drugs@FDA database (for current Invokana prescribing information): https://www.accessdata.fda.gov/scripts/cder/daf/

Trial names (CANVAS, CREDENCE, EMPA-REG OUTCOME, EMPA-KIDNEY, PROactive, UKPDS) are referenced by name; specific figures associated with these trials vary between sources and have not been independently confirmed here.