Medications Intro

This section on diabetes medications addresses key questions for diabetes educators to ask prior to adjusting or adding medications. Additionally, you'll find links to pages on medication classes and to our complete diabetes medications table.

1. Introduction to diabetes medication classes

Drug classes differ by their mechanism of action, A1c lowering capacity, side effects, risk of hypoglycemia, effect on weight and vascular protection. Click the class headings below to review these and specific brand considerations. To view brand indications, doses and cost visit the Complete Diabetes Medication Table.

2. Are medication changes needed?

Prior to adjusting or adding more medications to address hyperglycemia, consider these questions:

  • Adherence: 
    • Does the client take medication as prescribed?
    • Will increased adherence  impact glycemic control?
    • Can a simplified regimen with combination medications or once daily versions of medications improve adherence? If yes, are they affordable?   
  • Safety: 
    • Are there safety issues to consider prior to changing medication dose or adding another class of diabetes medication? Consider:
      • Risk of hypoglycemia (commercial driver, frail elderly etc),
      • Ability to adhere to the complexity of the new regime
      • Use with comborbidities (e.g. chronic kidney disease)
      • Risk of DKA Ability and willingness to test for ketones if esting ketones if any DKA symptoms rather than assuming symptoms are illness if increasing to higher SGLT-2 maintenance dose. 
  • Lifestyle: Can lifestyle changes help to improve glycemia? If adequate beta cell function remains in type 2 diabetes, lifestyle changes could potentially reduce A1c by 0.5-2.0% depending on the type and extent of the change.  Consider offering the Worksheet: Managing Blood Sugars.

  • A1c:
    • How much does A1c need to change to reach individualized target? 
    • Will some drugs be more effective than others in getting A1c into target? 
    • Is it necessary to add in another medication? (eg. frail elderly with A1c 8.0%)
  • Current medication dose change:
    • Will an adjustment to their current medication likely bring them to target or is another agent also needed? E.g. if A1c is 10% and client is on maximum metformin with near maximum gliclazide, consider an increase to the latter with a simultaneous request for another agent to be added. Maximum daily doses are outlined in our Complete Diabetes Medications Table.
    • Are there factors that would suggest a more aggressive dose adjustment (prednisone, minimal effects of last adjustment, obesity)?
    • Are there factors that would suggest a more conservative dose adjustment?  (frail, low eGFR, inability to self-treat hypoglycemia, lean patient, anticipated rapid weight loss with bariatric surgery, planned significant dietary changes, planned increased exercise, history of severe hypoglycemia, fear of hypoglycemia, etc)?
    • Will the dose change address the blood glucose pattern? 
    • What do you anticipate will happen to the glucose pattern after the medication adjustment? Are there safety concerns to address with the patient now or when blood sugars drop to a certain level? Eg. If patient is on repaglinide tid with basal insulin and has high readings only at bedtime (and in low target range at breakfast). A reduction to overnight basal insuiln might be considered when the supper repaglinide is increased to avoid overnight or fasting hypoglycemia. 

3. What medication class is next?

​The use of two medications from the same class is generally not indicated E.g. two secretagogues or 2 incretin-based medications (DPP-4 and GLP-1). To learn Health Canada indications and doses, visit the Drug Product Database or our Complete Diabetes Medications Table

A. Consider the Diabetes Canada's tool "Pharmacotherapy for Type 2 Diabetes" to help decide next line agents. Sort by the most relevant features for your client:

  • Relative A1c Lowering
  • Hypoglycemia 
  • Weight
  • Effect in Cardiovascular Outcome Trial (vascular protection)
  • Other therapeutic considerations (safety of drug with comorbidities)
  • Cost
  • Additional considerations: Patient preference  and adherence (consider once-daily/once weekly dosing if adherence is a concern) 

B. Consider Renal Impairment:

4. Drug Interactions

Patients should review potential drug interactions or side effects with pharmacists when starting any medication. Educators can review interactions in product monographs via Canada's Drug Product Database. A few interactions that impact glycemia are listed below. 

Hypoglycemia risk increases with:

  • Beta blockers – may decrease symptoms of lows
  • Salicylates/NSAIDs – if 4-6 g/day or greater
  • Antibiotics: Fluoroquinolones (e.g. ciprofloxacin) can stimulate beta cells to secrete insulin. Hypoglycemia has been reported in patients without diabetes and in patients with diabetes on any antihyperglcyemic agent, especially those on insulin or secretagogues.

Hyperglycemia risk increases with:

  • Glucocorticoids- including those injected for joints
  • Thiazide diuretics – at doses > 25 mg/day