Invokana Insights: 10 Drug-Specific Facts You Should Know
Medically reviewed on Mar 14, 2017 by L. Anderson, PharmD.
1. Invokana Is Canagliflozin: How Does It Work?
If you or a family member have been diagnosed with prediabetes or type 2 diabetes, this slideshow is important for you. Invokana, known generically as canagliflozin, is a newer class of drugs called the sodium-glucose transporter-2 (SGLT2) inhibitors. These drugs are oral hypoglycemics (drugs used to lower blood sugar) in patients with type 2 diabetes. The SGLT2 inhibitors block the kidney from reabsorbing sugar (glucose). In turn, you eliminate more glucose in your urine which lowers your blood sugar levels. Invokana is also associated with reductions in blood pressure and weight loss, and was the first SGLT2 inhibitor FDA-approved in March 2013.
2. Invokana: When to Start?
When someone is first diagnosed with diabetes, they will not typically start with Invokana alone as an initial treatment. Invokana is usually added on to other diabetes treatments, such as metformin, sulfonylureas, or insulin, as an "adjunct", when a patient no longer responds, or if the blood sugar level is too high at the outset.
The SGLT-2 drugs, which come as oral tablets, are sold as individual agents and in combination with other diabetes drugs: Invokana (canagliflozin), Invokamet (canagliflozin/metformin), Farxiga (dapagliflozin), Xigduo XR (dapagliflozin/metformin extended-release), Jardiance (empagliflozin), Glyxambi (empagliflozin/linagliptin), and Qtern (dapagliflozin/saxagliptin)
However, the combination agents like Invokamet that contain metformin may be appropriate to start as a first-line agent in certain patients who will need greater blood sugar control.
3. How Effective Is Invokana?
Invokana is used with other diabetes meds to lower blood sugar. In studies it lowered A1C (a measure of blood sugar control) up to 0.7 percent, so it's a weak blood sugar lowering agent. However, Invokana is usually used as an "adjunct" (added to) to metformin, which boosts blood sugar control.
Luckily, there's a combined pill that makes it easier. Invokamet contains both metformin and canagliflozin in one tablet, which may be more convenient. When compared to Januvia (sitagliptin) plus metformin, Invokana plus metformin has been shown to be better at lowering blood sugar and also leads to weight loss. In fact, studies have shown metformin plus canagliflozin led to a 10-pound weight loss over one year in some patients, which is a big advantage in diabetes.
4. Who Should Not Use Invokana?
Invokana was developed to treat type 2 diabetes; it is not to be used to treat type 1 diabetes. Invokana works in the kidneys, so you should not use Invokana if you have severe kidney problems or are on kidney dialysis. Your doctor will check your kidneys to see how well they work before you start Invokana or Invokamet, and periodically thereafter. If you notice signs of kidney injury, like decreased urine or swelling in the legs or feet, be sure to contact a healthcare provider immediately. If you've had an allergic reaction in the past to canagliflozin - such as a rash, hives, or swelling - you should also not use Invokana.
Invokana should not be used to treat a condition called diabetic ketoacidosis, which is a potentially deadly complication of diabetes when you do not have enough insulin. In ketoacidosis, your blood becomes acidic (the pH is too low). In fact, on the next slide, you'll see some news the FDA released in May 2015 on SGLT2 Inhibitors causing ketoacidosis.
5. FDA: Other Warnings with Canagliflozin
Ketoacidosis usually occurs in patients with type 1 diabetes. However, in May 2015, the FDA issued an important warning that the SGLT2 inhibitors like canagliflozin can infrequently cause ketoacidosis, usually in less than 1 out of every 100 patients. Major illness, reduced food and fluids, and reduced insulin doses can also cause ketoacidosis. The FDA stated that patients who experience signs or symptoms of ketoacidosis (such as trouble breathing, nausea, vomiting, abdominal pain, confusion, unusual fatigue or sleepiness) should contact their doctor immediately to determine if they have ketoacidosis, as drug treatment may need to be halted.
Also, the FDA warned that patients taking canaglifozin should notify their doctor right away if they notice any new pain, tenderness, sores, ulcers, or infections in their legs or feet. Plus, patients should talk to their doctor about factors that may increase their risk for bone fracture.
6. Invokana Side Effects: What Do You Need to Know?
The most common Invokana side effects include:
- Yeast infections in vagina or penis
- Urinary tract infections or frequent urgent need to urinate
- High blood potassium levels
- Kidney disease
- Low blood sugar (especially when used with other diabetes drugs)
- Serious allergies/angioedema
7. Invokana: Drug and Dose Specifics
Your doctor will review how well your kidney works before and during treatment with Invokana; you need good kidney function to take Invokana as that's where the drug works.
Invokana is taken by mouth, and it comes in 100 milligram (mg) and 300 mg tablets. Usually, most patients will start at the 100 mg dose. You should take Invokana once a day before your first meal.
If your blood sugar control is not adequate, your doctor may decide a higher Invokana dose is needed (but only if your kidney function is good enough for the higher dose) .
8. What Other Medicines Do You Take?
Drug interactions should always be assessed whenever you start - or even stop - a medication. Like most other medicines, Invokana has drug interactions.
UGT enzyme inducers speed up removal of Invokana from the body and make it less effective. In patients who take UGT enzyme inducers (such as rifampin, phenytoin, phenobarbital, or ritonavir), higher doses of Invokana may be needed to control blood sugar.
9. I Missed My Dose of Invokana. What Should I Do?
Low blood sugar is not common with normal doses of Invokana. If you missed your dose of Invokana, take it as soon as you remember. But if it is almost time for next dose, skip the missed dose and take Invokana at your regularly scheduled time.
It is very important you do not take two doses of Invokana at the same time, unless your doctor instructs you to do this. Taking too much Invokana may lower your blood sugar too much. Signs of low blood sugar include: headache, drowsiness, weakness, dizziness, confusion, hunger, a fast heartbeat, sweating, and a shaky feeling. Always keep a source of sugar, like fruit juice, hard candy, or crackers with you in case you have low blood sugar.
10. Can I Afford To Buy Invokana?
Since Invokana is a relatively new medicine, lower cost generics for this drug will not be available for many more years. The retail cash price for this drug varies around the country, but in general may run from $350 to 450 per month. Your insurance may cover all or some of the cost of this medication.
If you are not able to afford your medication, do not hesitate to speak to your doctor about this. It may be that another more affordable medication can be prescribed. If needed, Janssen, the manufacturer of Invokana, may be able to offer cost assistance for Invokana if you qualify. You can call them at 1-877-468-6526.
Finished: Invokana Insights: 10 Drug-Specific Facts You Should Know
- Invokana Professional Information. (FDA Package Insert). Drugs.com. Revised: 03/2015. Accessed August 15, 2016 at https://www.drugs.com/pro/invokana.html
- FDA Issues Warning for Type 2 Diabetes Drugs. Drugs.com. May 18, 2015. Accessed August 15, 2016 at https://www.drugs.com/news/fda-issues-warning-type-2-diabetes-56840.html
- SGLT2 inhibitors: Drug Safety Communication - FDA Warns Medicines May Result in a Serious Condition of Too Much Acid in the Blood. Drugs.com. May 2015. Accessed July 16, 2015 at https://www.drugs.com/fda/sglt2-inhibitors-safety-communication-fda-warns-medicines-may-result-serious-condition-much-acid-13717.html.
- FDA Alert. New Drug Approved for Type 2 Diabetes. Drugs.com. April 1, 2013. Accessed August 15, 2016 at https://www.drugs.com/news/new-approved-type-2-diabetes-43918.html
- Canagliflozin (Invokana, Invokamet) and Dapagliflozin (Farxiga, Xigduo XR): Drug Safety Communication - Strengthened Kidney Warnings. Drugs.com. June 14, 2016. Accessed August 15, 2016 at https://www.drugs.com/fda/canagliflozin-invokana-invokamet-dapagliflozin-farxiga-xigduo-xr-safety-communication-strengthened-13888.html
- Canagliflozin (Invokana, Invokamet): Drug Safety Communication - Clinical Trial Results Find Increased Risk of Leg and Foot Amputations. Drugs.com May 18, 2016. Accessed August 15, 2016 at https://www.drugs.com/fda/canagliflozin-invokana-invokamet-safety-communication-clinical-trial-results-find-increased-risk-13878.html
- Invokana and Invokamet (canagliflozin): Drug Safety Communication - New Information on Bone Fracture Risk and Decreased Bone Mineral Density. Drugs.com. Sept. 10, 2015. Accessed August 15, 2016 at https://www.drugs.com/fda/invokana-invokamet-canagliflozin-safety-communication-new-bone-fracture-risk-decreased-bone-mineral-13763.html