New way to fight diabetes.
Canagliflozin, the newest Food and Drug Administration-approved drug of its class, was approved on March 2013 as an adjunct to diet and exercise to improve glycemic control in type 2 diabetes patients. In type 2 diabetes patients, the body does not secrete enough insulin or the cells have insulin resistance. Insulin is needed for the body to use glucose for energy. If there is an abundance of glucose in the bloodstream and not enough insulin, it can lead to diabetic complications (affecting eyes, feet, etc.).
Normally, an individual has a blood glucose level of 70 to 120 mg/dl, but if that level is exceeded to 160 to 180 mg/dl the glucose will start to spill over in the urine. Once perceived as a metabolic compensatory mechanism by the body in order to combat the diabetic condition, the excretion of glucose is now advocated by the new drug canagliflozin in order to lower the glucose levels in the blood.
Canagliflozin (Invokana) increases glucose excretion, independent from insulin secretion by blocking the transporter (SGLT2) responsible for 90% of glucose reabsorption in the proximal tubules of the kidneys, and lowers the renal threshold for glucose. It also increases insulin sensitivity, increases the amount of glucose absorbed in the muscles, decreases production of glucose and improves insulin release from the beta cells.
The data on the drag showed lower Alc levels, weight loss around 300 to 400 kcals per day, mild suppression of blood pressure and virtually no hypoglycemia. This makes the drug a more likely choice over sulfonylureas, which can cause weight gain and hypoglycemia.
The FDA focused on nine trials for the approval of canagliflozin, which indicated it to be non-inferior to glimepiride and sitagliptin. In Janssen's cardiovascular study, CANagliflozin cardioVascular Assessment Study (CANVAS), there was a nonsignificant increase in major adverse cardiovascular events within the first 30 days of initiating therapy. So far, the new medication has shown positive outcomes and serves as a potential alternative to other anti-hyperglycemic agents (AHAs).
Invokana is not indicated for the treatment of type 1 diabetes mellitus or diabetic ketoacidosis. It is manufactured and supplied as 100- and 300-mg tablets and taken orally once daily. The recommended starting dose is 100 mgs orally before the patient's first meal of the day and can be titrated up to 300 mg based on the patient's tolerance to the medication. 100 mgs is suggested in patients with a GFR of 60-45 ml/min/1.73m2 and is not initiated if lower than 45ml/min/1.73m2. It is not indicated for patients younger than age 18. There are no active metabolites, and the half life of Invokana is 11 to 13 hours at once-a-day dosing.
There should be continuous monitoring of fluid intake and volume along with blood pressure when taking this medication, because its mechanism of action dictates diuresis. It is imperative that diet and exercise is also stressed when taking this medication, to reach optimal results.
Patients should increase their daily fiber intake and limit the amount of carbohydrates taken in a day to between 100 grams and 150 grams. Non-weight-bearing exercises should be recommended to the patients, such as swimming, bicycling, rowing and chair and arm exercises.
Without these key instructions, lowering Alc levels and promoting weight loss is not as significant.
The most common side effects with Invokana are mycotic infections (vaginal yeast infections and urinary tract infections). The highest risk of infections is seen in female patients and men who have not been circumcised. Some other adverse reactions associated with canagliflozin (Invokana) include hypotension, impairment of renal function, hyperkalemia, hypoglycemia with concomitant use with insulin and insulin secretagogues, hypersensitivity reactions and an increase in low-density lipoproteins (LDLs).
Since canaglifiozin potentially serves as an osmotic diuretic, hypotension should be monitored in patients with impaired renal function, patients with low blood pressure and those taking diuretics, angiotensin-converting enzyme inhibitors or angiotensin receptor blockers. This medication may also cause hyperkalemia, so monitoring for medications that may cause a rise of potassium in some patients is in order.
A lower dose of insulin and/or insulin secretagogues may be needed to reduce the risk of hypoglycemia when taken with Invokana. The increasing LDL levels observed are dose-dependent on Invokana, so the consideration of lowering the dose until symptoms resolve should also come into play.
The long-term effects of this drug on the urinary tract remain to be seen, and the thoughts of the kidney's not developing a metabolic form of compensation are questionable. However, most of the AHAs that we already have on the market are either insulin secreatagogues, glucose dependent or try to utilize glucose in the body in one way or the other.
Canagliflozin, on the other hand, operates differently: It provides an escape mechanism for glucose.
Canagliflozin's new mechanism of action provides a paradigm shift for this new era and a potential resolution for the diabetic condition.
Stephen Freed, B. Pharm., is a diabetes educator and the publisher of www.diabetesincontro.com.
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|Publication:||Chain Drug Review|
|Date:||Aug 5, 2013|
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