Every FNP candidate knows that metformin is the first-line oral agent for type 2 diabetes. The exam knows that you know. So the exam doesn't ask you about metformin — it asks you about everything that comes after.
This is where most candidates lose points. They have a strong handle on the first step and a wobbly grasp on steps two, three, and four. Let's fix that.
Diabetes management on the boards is about the algorithm. Memorize the algorithm and the questions become predictable.
The Diagnostic Criteria
Diabetes is diagnosed by any of:
- A1c ≥ 6.5%
- Fasting glucose ≥ 126 mg/dL
- Random glucose ≥ 200 with symptoms
- OGTT 2-hour glucose ≥ 200 mg/dL
Prediabetes: A1c 5.7–6.4%, fasting glucose 100–125, OGTT 140–199.
Treatment Targets
- A1c < 7% for most adults
- Less strict (<8%) for older adults with limited life expectancy or significant comorbidities
- Stricter (<6.5%) for younger patients with short duration and no comorbidities
- BP <130/80
- LDL <100 (or <70 if known ASCVD)
- Statin therapy for most diabetics 40 to 75
The First-Line Drug
Metformin. Start 500 mg daily, titrate to 2000 mg/day in divided doses. Hold if eGFR < 30. Caution if eGFR 30–45. Side effects: GI upset (improves with extended-release or with food), rare B12 deficiency, rare lactic acidosis.
When Metformin Isn't Enough
If A1c is still above goal after 3 months on max metformin, add a second agent. Here's where the question gets nuanced — the exam wants you to choose based on patient comorbidities, not just sugar reduction.
Patient has known cardiovascular disease or heart failure
Add a GLP-1 agonist with proven CV benefit (liraglutide, semaglutide, dulaglutide) OR an SGLT-2 inhibitor (empagliflozin, canagliflozin, dapagliflozin). These reduce major adverse cardiovascular events independently of glucose reduction.
Patient has heart failure (especially HFrEF)
SGLT-2 inhibitor is first-line add-on. Strong evidence of mortality benefit in HF.
Patient has chronic kidney disease
SGLT-2 inhibitor is first-line add-on. Slows progression of CKD.
Patient needs significant weight loss
GLP-1 agonist. Tirzepatide (a GIP/GLP-1 combo) is even more effective for weight.
Cost is a major concern
Sulfonylurea (glipizide, glimepiride). Cheap, effective for sugar, but causes weight gain and hypoglycemia. Or pioglitazone.
Test Pearl: The exam wants you to match the second agent to the patient's comorbidity, not just lower sugar. Read for diabetes plus what other disease they have.
When to Start Insulin
- A1c > 10% at diagnosis with symptoms
- A1c remains uncontrolled despite triple oral therapy
- Catabolic symptoms (significant weight loss, ketosis)
- Pregnancy with poorly controlled T2DM
Start with basal insulin (glargine, detemir, degludec) at 10 units daily or 0.1–0.2 units/kg, titrate by 2 units every 3 days based on fasting glucose.
Hypoglycemia Management
- Glucose < 70 with symptoms — 15 grams fast carbs, recheck in 15 minutes.
- Severe hypoglycemia (unconscious) — glucagon IM or D50 IV.
- Drugs that cause hypoglycemia: sulfonylureas, insulin, glinides. NOT metformin, GLP-1s, SGLT-2s, DPP-4s, or pioglitazone (in monotherapy).
Monitoring
- A1c every 3 months until at goal, then every 6 months.
- Annual urine albumin/creatinine ratio for nephropathy.
- Annual dilated eye exam.
- Annual comprehensive foot exam.
- Lipid panel annually.
Diabetes Plus Pregnancy
- Pre-existing T1 or T2DM in pregnancy: insulin is preferred.
- Gestational diabetes: diet first, then metformin or insulin if not at goal. Glyburide has fallen out of favor.
- Screening for GDM: 24–28 weeks with 50g glucose load.
What Trips Candidates Up
- Not adjusting metformin for renal function.
- Picking a sulfonylurea when the patient has heart failure (wrong — pick SGLT-2).
- Forgetting that GLP-1s help weight loss AND CV outcomes.
- Missing the CKD-specific drug choice.
Build the algorithm. Drill it. Diabetes will become predictable.