Example 1: The treatment naÔve patient
You are looking after a 76 y.o male admitted with TIA. No known prior hx of DM. Found to have A1C of 7.5% and fasting BG of 9.8 mmol/L. What OAHA(s) would you select (together with lifestyle measures)?
1. Start with the A1C. Decide what the target should be (7.0%). Remembering that each class of OAHA lowers A1C by ~ 1.0%, one class should be enough to get his A1C to target.
2. Metformin should be first-line treatment and used if no contraindications (e.g. GFR < 30 mL/min). Start metformin at a dose of 500 mg bid.
3. Remember metformin can take 1-2 weeks to start to work. Fortunately in this case, his BS are not too high so it would not be essential to use another agent that would work more quickly.
Example 2: The treatment naÔve patient, with higher BS
What if the patient above had an A1C of 7.8%, but his BS have been 15-20 mmol/L? Would your management differ?
1. Like Example 1, based on the degree of A1C elevation, one medication should be enough to get the A1C to target. Metformin should be the first option provided there are no contraindications.
2. However, since metformin may take 1-2 weeks to work, and his BS are quite high, you may consider using metformin TOGETHER with something that works quick (e.g. an insulin secretagogue) short-term. This way the other medication can work to lower BS while waiting for metformin to start working.
3. Once metformin starts to work, can then decrease or stop the other medication.
Example 3: What to use after metformin.
A 55 y.o female with T2DM admitted with syncope takes metformin 1000 mg bid. Her A1C is 7.9%. What would you add?
1. She is on the maximal effective dose of metformin. While her A1C is above the target of 7.0% or less, it is not far from it. Theoretically, adding one more medication will be able to reduce her A1C to below target.
2. There are multiple potential answers for the choice of the added agent. It really does depend on the patientís profile and factors such as finances, risk for hypoglycemia, weight and preference.
a) An insulin secretagogue is a good option. There is long-term data for their use and they are affordable. A good choice is gliclazide 80 mg bid which can be titrated to 160 mg bid, or gliclazide MR 30 mg once daily to be titrated to 120 mg daily.
b) However, if this patient has had problems with hypoglycemia and/or is at risk for hypoglycemia, you would really need to balance this risk against the benefits.
c) Incretin-based therapy is another good option given its low potential for hypoglycemia. However, if she does not have drug insurance, she is unlikely to be able to afford it.
d) A TZD (insulin sensitizer) is another option that has low potential for hypoglycemia. However, it does cause weight gain and should be prescribed carefully in patients with or at risk for cardiovascular disease.
Example 4: Thinking beyond oral agents
A 68 year old man is admitted with a diabetic foot infection. He is on maximal doses of 3 OAHA's, and is found to have an A1C of 9.2%. How can you optimize his therapy?
Answer: Given the fact that his A1C is 9.2%, adding an additional class of oral agent will theoretically only reduce it by 1.0% down to 8.2%, which is still above target. It should be recommended to the patient that he start insulin therapy. See insulin initiation section for more info.
Example 5: Stress-induced hyperglycemia
You are looking after a 59 y.o female with T2DM admitted with pyelonephritis. Her A1C is found to be 7.5%, and she is on metformin 500 mg bid. Her Accuchecks are averaging 14 mmol/L in hospital. What do you do?
Answer: Remember that in acutely ill patients, hyperglycemia is common due to increased levels of counter-regulatory hormones and decreased exercise. This patient, however, was suboptimally controlled even before hospitalization with her A1C of 7.5%. Assuming her renal function is normal, she is tolerating her metformin well, and no CT with contrast is planned for this patient, one can certainly ↑ her metformin to 1,000 mg bid. However, this will take several weeks to have its full effect. Thus, until this occurs, it would be reasonable to add a sulfonylurea, such as glyburide 5 mg bid (if she has no drug plan) or gliclazide MR 30 mg daily (if she has a drug plan).
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