Canagliflozin: what it treats, how to take it, side effects
Last updated September 3, 2026.
Canagliflozin is an SGLT2 inhibitor - it makes the kidneys send more glucose out in the urine. You may know it as Invokana. Beyond blood sugar, it protects the heart and kidneys in certain people with type 2 diabetes - and it carries a warning list that deserves a careful read.
What does it treat?
Lowering blood sugar in type 2 diabetes; reducing the risk of stroke, heart attack, or death in certain people with type 2 diabetes; and reducing the risk of worsening kidney disease, heart-failure hospitalization, and death in certain adults with type 2 diabetes and kidney disease. Not type 1 diabetes. It controls diabetes; it does not cure it.
How do you take it?
One tablet once a day before breakfast or the first main meal, same time every day. Your doctor may start low and increase gradually. Keep taking it when you feel well; never stop without your doctor. Because it works through the kidneys and urine, the daily habits are hydration and foot care: check your feet every day for pain, tenderness, sores, ulcers, or warm red swollen areas, and call right away about any of them - the drug raises the risk of lower-limb amputation, and foot care is the counterweight. It can also raise the chance of fractures, especially arms, wrists, hands, lower legs, ankles, and feet. Missed dose: take it when you remember unless the next one is close; never double up.
Side effects to know
- Common: more frequent urination, thirst, and genital yeast infections - sugar in the urine feeds them.
- Serious - call your doctor immediately: urinary-tract signs - frequent, urgent, burning, or painful urination, cloudy, red, pink, or brown or strong-smelling urine, pelvic or rectal pain, or fever with back pain, nausea, or vomiting; genital infection signs - in women, vaginal odor, white or yellowish discharge, or itching; in men, redness, itching, or swelling of the penis, rash, or foul-smelling discharge; tiredness or weakness with fever and pain, tenderness, redness, or swelling of the genitals or the area between genitals and rectum; and falls. Stop and get emergency care for rash, hives, swelling of the face, throat, or tongue, or trouble breathing - and for ketoacidosis: nausea, vomiting, stomach pain, tiredness, or difficulty breathing, even if your blood sugar reads under 250.
Who should not take it?
Not for type 1 diabetes. Flag kidney disease, a history of urinary tract or genital yeast infections, foot problems or prior amputation, low blood pressure, and bone-fracture risk before starting. Surgery, illness, or reduced eating can push toward ketoacidosis - ask your doctor for the sick-day rules before you need them. If you become pregnant, call your doctor.
When is it an emergency?
Nausea, vomiting, stomach pain, and trouble breathing together - ketoacidosis, possible even at normal-looking glucose readings - is emergency care, as is throat swelling or trouble breathing. For an overdose, call Poison Control at 1-800-222-1222. Pymander's escalation routing is built and tested specifically for this class of decision; see the safety architecture working paper.
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Common questions
Why does canagliflozin come with an amputation warning?
MedlinePlus states it directly: canagliflozin can increase the risk of lower-limb amputation - toe, foot, or leg. The mechanism runs through the foot problems diabetes already causes, which is why the counterweight is daily foot care: your doctor teaches you how to check and care for your feet, and any pain, tenderness, sores, ulcers, or swollen, warm, reddened areas - plus fever or chills - mean calling right away. The warning is real, and so is the defense.
Why do I keep getting yeast infections on this drug?
The mechanism is the cause: canagliflozin puts extra sugar in your urine, and sugar feeds yeast. MedlinePlus lists genital yeast infections as expected side effects - vaginal discharge, odor, and itching in women; redness, itching, rash, or foul-smelling discharge of the penis in men. Treatable and worth reporting, and hygiene plus hydration reduce recurrence. Fever with pain, redness, or swelling of the genital area is the rare, serious version - that one is immediate.
Why did my doctor mention ketoacidosis if my sugar is controlled?
SGLT2 inhibitors can cause ketoacidosis at deceptively normal glucose levels - MedlinePlus says to check urine ketones if you get nausea, vomiting, stomach pain, tiredness, or difficulty breathing, even if blood sugar is under 250. It shows up most when the body is stressed: illness, surgery, eating much less. Those are the days to check ketones, not just glucose.
Why am I urinating so much more on canagliflozin?
That is the drug working - its job is escorting glucose out through urine, and glucose takes water with it. More trips and more thirst are the expected signature. The management is drinking enough, and the watch-item is the line where expected becomes urinary-tract infection: burning, urgency, cloudy or bloody or strong-smelling urine, pelvic or back pain, fever. Those get a call.
Why did my doctor ask about my bones?
Canagliflozin may increase the chance of fractures, particularly in the arms, wrists, hands, lower legs, ankles, and feet - MedlinePlus says to talk to your doctor about the risk. Combined with the falls item on the serious list, the practical reading is: bone-protective habits matter, and dizziness deserves respect, especially on standing.
What happens if I miss a dose of canagliflozin?
Take it as soon as you remember, unless it is almost time for the next one - then skip it and never double up. It is anchored before breakfast or the first main meal; if breakfast is long past, the cleaner move is usually to skip and take tomorrow's on time rather than stack doses.