Digital PharmD

Informatics in Pharmacy

diabetes

Diabetes

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This is a very simply rundown of diabetes.  The diabetes information on the ambulatory care board exam is more complex.  Knowing the basics of how to diagnose diabetes, goals, how to change insulin and which drugs not to use in which patients is probably enough for the BCPS.

Pre-Diabetes

  • Fasting Plasma Glucose: 100-125 mg/dl
  • 2-hour plasma glucose test: 140-199 mg/dl
  • A1C = 5.7-6.4%

Diagnostic Criteria:

  • Fasting plasma glucose >=126 mg/dl
  • Casual plasma glucose >= 200 mg/dl
  • 2-hour post load glucose >= 200 mg/dl
  • A1C >= 6.5%
  • *Must have 2 positive tests before diagnosis.
  • C-peptide can be a sign of type 2 diabetes.

Goals:

  • A1C < 7.0 (some sources say 6.5).  If at goal, measure every 6 months, if not measure every 3
  • FPG or pre-meal = 80-130 mg/dl
  • Post-prandial (1-2 hours after meal): <180 mg/dl
  • Acute complications: Hypoglycemia, DKA, hyperglycemia, hyperosmolar non-ketonic syndrome
  • Long-term complications:
    • microvascular: retinopathy, nephropathy, neuropathy
    • macrovascular: cardiovascular disease, cerebrovascular disease, peripheral vascular disease

Gestational Diabetes:

  • Fasting plasma glucose of 92 or greater or 1-hour OGTT >180, 2-hr >153
  • Goals are different: FPG <95, 1-h PP <140, 2 h-pp <120

Insulin Therapy Management:

  • Estimate total daily insulin requirement (0.3 to 0.6 unit/kg/day).  May need less at start of therapy (honeymoon phase)
  • Old school: give 2/3 dose before morning meal (2/3 as NPH, 1/3 as regular) and 1/3 before evening meal (2/3 as NPH, 1/3 as regular)
  • Newer method: Give 50% as basal insulin (determir, glargine or degludec) and 50% as fast acting (aspart, lispro, glulisine) three times a day before meals.

PO Medications:

  • Metformin is drug of choice.  Reduces A1C by 1-2 %. Do not give if CHF or increased CR (lactic acidosis is possible).
  • Sulfonylureas: Can cause hypoglycemia.  Reduce A1C by 1-2% (glyburide, glipizide, glimepiride).
  • Meglitinides: They are basically rapid acting sulfonylureas. Can also cause hypoglycemia. Reduce A1C by 0.5-1.5% (repaglinide or nateglinide)
  • Thiazolidinediones: contraindicated in hepatic impairment and class III/IV heart failure.  Reduces A1C by 0.5-1.4%  Also reduces HDL (pioglitazone and rosiglitazone.
  • DPP-4 Inhibitors: Reduce A1C by 0.5-0.8%.  No hypoglycemia. Can cause respiratory infections, UTI, joint pain, headache, angioedema, Stevens-Johnson, pancreatitis (sitagliptin, saxagliptin, linagliptin, alogliptin).
  • SGLT-2 Inhibitors: Reduce A1C by 0.3-1.0%.  Can cause UTI, hypotension (canagliflozin, dapaliflozin, empagliflozin).

Ketoacidosis

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Ketoacidosis is more common in type 1 diabetes than in type 2.  The goal treatment is to stop ketosis, not to normalize glucose.

Common symptoms: polyuria, polydipsia, vomiting, dehydration, weakness, altered mental status, coma, abdominal pain, Kussmaul respirations, tachycardia, hyponatremia, hyperkalemia

Treatment:

  1. Fluid replacement: start with 0.45-0.9% NS, change to 5% dextrose or dextrose containing saline when glucose is less than 200 mg/dl.
  2. Correct serum sodium(for every 100mg/dL increase over 100 in glucose, increase sodium by 1.6).  Usually, 0.9% NS, do not rapidly correct sodium ever.
  3. If potassium is less 3.3 mEq/L, replace KCl before giving insulin.
  4. Insulin: 0.1 unit/kg bolus and then infusion ONLY if KCl is greater than 3.3 mEq/L.  Keep glucose 150-200 mg/dl until DKA resolves.
  5. If pH <= 6.9 – Give bicarb over 1-2 hours
  6. DKA is resolved when serum glucose is less than 200 and 2 of the following:
    Venous pH >  7.3
    Bicarb 15 mEq or greater
    Anion gap of 12 mEq or less

If you prefer charts, here’s one I downloaded for my notes.