Things a Pharmacist Must Know About Insulin by 1N8kvXp


									                                Insulin Pearls for the Pharmacist
1. Insulin can be divided into three categories:
        Basal - the amount of exogenous insulin necessary to maintain euglycemia in the absence of
        Prandial or Nutritional - the amount of insulin necessary to cover intravenous dextrose, total
            parenteral nutrition, enteral feedings, or discrete meals
        Correction –the amount of insulin necessary to correct current hyperglycemia

2. There are now several insulin analogs available. These analogs are made using recombinant DNA
   technology to alter the amino acid sequence of human insulin such that absorption from
   subcutaneous injection is altered. These structural changes do not affect the action once absorbed,
   and thus analogs should NOT be used for IV administration (the effect would be the same as regular
   human insulin)
        Glargine (Lantus ) –more acidic than regular human insulin due to amino acid changes, and

           thus when injected subcutaneously shift the isoelectric point making insulin glargine less
           soluble at physiologic pH, and thus prolonging systemic absorption to approximately 24 hours
           in a majority of patients without a notable peak.
        Detemir (Levemir ) –Insulin detemir has a fatty acid side chain that allows albumin binding,

           primarily resulting in association with tissue-bound albumin at the injection sites, which leads
           to prolongation of action, and allows for once or twice daily administration without a notable
           peak. It was approved in June 2005 and is scheduled to be marketed in early 2006.
   RAPID ACTING INSULIN ANALOGS – amino acid changes stabilize insulin monomers (more rapidly
   absorbed from subcutaneous injection) and inhibits hexamer formation (slower absorption)
        Insulin Lispro (Humalog )

        Insulin Aspart (Novolog )

        Insulin Glulisine (Apidra ) nonformulary at UW Medicine

3. Basal insulin ideally should mimic the secretion of insulin by a healthy pancreas in the absence of
   food. Options for basal insulin delivery include the following:

       Type of Insulin                Onset                  Peak                  Duration
                                     (Hours)                (Hours)                (Hours)
            NPH                         2                     4-6                    8-12
     Glargine (Lantus )                1-2                   NONE                     24
     Detemir (Levimer )                1-2                   NONE                   12-24

    A single type of basal insulin should be used in most patients. Any orders for more than one type of
    basal insulin should be clarified.

4. Prandial or food insulin ideally should mimic the secretion of insulin by a healthy pancreas in
   response to food ingestion. Options for prandial insulin delivery include the following:

    Type of Insulin          Onset               Peak              Duration           Lag Time
                           (minutes)            (Hours)            (hours)
         Regular             30- 60               2-4                6-8                 30
          Aspart              5-15                 1                  3-5               0-15
         Glulisine           10-20                1.5                 4-5

UWMC Dept of Pharmacy
JKelly 2/25/2012
    Rapid acting analogs are the preferred prandial insulin for most patients because their onset and
    duration better match the absorption of carbohydrate and the resultant rise in blood glucose. Fat and
    protein delay the absorption of carbohydrate, and thus if a patient eats high fat/protein meals, such as
    pizza or McDonalds, regular insulin may be a better choice. Also if a patient has gastroparesis or is
    receiving pramlintide, both of which delay the absorption of food, regular insulin may be a better
    option for prandial insulin. We have also found regular insulin to be better in oncology inpatients that
    frequently take several hours to consume the contents of a meal tray. Some patients will use more
    than one type of prandial insulin, but orders for combinations of prandial insulin should be double-
    checked. Typically patients need a larger dose of insulin with breakfast for the same amount of food
    than when the food is eaten later in the day. This is called the Dawn Phenomenon, and is the result
    of growth hormone secretion in the wee hours, which increases insulin resistance.

    *U-500 insulin is concentrated (5X) regular insulin that should be used ONLY in patients that are
    known to be insulin resistant. Its use is restricted to Obstetrics; however, occasionally other patients
    will need it. Verify that patient is taking greater than 50 units of U-100 insulin with each meal before
    dispensing. Unfortunately U-500 syringes are no longer available, and thus U-500 insulin is ordered
    as a measure of volume in a U-100 syringe

5. Rapid acting analogs should be used for correction of premeal or bedtime hyperglycemia. They are
   ADDED to the prandial/nutritional insulin. The rationale for using rapid acting analogs is that if you
   have hyperglycemia now you want insulin that will act now, and be gone once the hyperglycemia is
   corrected. Shortcomings of sliding scale insulin and how are algorithms different from sliding scale?
   (See Drug Therapy Topics Oct 2002):

6. Physiologic insulin regimens attempt to mimic the normal pancreatic secretion patterns, and therefore
   must consist of both basal and prandial insulin. In contrast nonphysiologic insulin regimens do not
   attempt to mimic normal pancreatic function, but merely boost the normal pancreatic secretion. Thus
   nonphysiologic insulin regimens should ONLY be used in patients with Type 2 diabetes with sufficient
   pancreatic function remaining. Pancreatic function declines in a linear fashion over time in patients
   with Type 2 diabetes, and thus eventually most patients with Type 2 diabetes will require a
   physiologic insulin replacement.

7. Typical daily insulin requirements are as follow:

    Type 1 (0.5-0.7 units/kg/day), however, newly diagnosed patients typically produce some insulin, and
    thus the daily insulin requirement may be lower during this honeymoon period. A honeymoon period
    does not occur in all patients (more common in adults than children), but if it occurs it happens within
    a couple weeks of diagnosis and adequately controlling the blood glucose with exogenous insulin.

    Type 2: highly variable and can exceed 1.5 units/kg/day in some patients. When starting a patient
    with Type 2 diabetes on insulin, start with a daily insulin requirement of 0.3unit/kg/day.

8. Developing an insulin regimen - how much prandial and how much basal?

    Intensive insulin management: patient must be willing and able to give 3 to 4 injections daily, and test
    blood glucose 3 to 4 times per day (patient's that really strive for tight control test 6 or more times per
    day). With intensive management about 50% of the daily insulin requirement is given as basal
    (typically Glargine once daily but occasionally NPH is given in smaller doses 4 times daily). The
    remaining insulin requirement is divided up and given as prandial insulin.

    Traditional Management: this is most often accomplished with NPH and regular. In this case the
    NPH is acting as both basal and prandial insulin so the 50/50 rule doesn't work. Most commonly the
    daily insulin requirement is divided up such that 2/3 is given in the morning (2/3 as NPH and 1/3 as
    Regular). In the evening the remaining 1/3 of the daily insulin requirement is given half as NPH and
    half as Regular. It is difficult to achieve tight control with this sort of regimen without excessive
    hypoglycemia. (See insulin action slides). Risk for nocturnal hypoglycemia is high with supper time
    NPH and can be reduced by moving NPH to bedime.

UWMC Dept of Pharmacy
JKelly 2/25/2012
9. There are several premixed insulin products on the market:
    70/30 (70% NPH and 30% Regular)* only premixed insulin on UW Medicine formulary
    Novolog 70/30 (70% aspart protamine suspension and 30% aspart)
    Humalog 75/25 (75% lispro protamine suspension and 25% lispro)
    50/50 (50% NPH and 50% Regular)

    Lispro protamine and aspart protamine are therapeutically equivalent to NPH.
    If a patient is admitted and uses one of these nonformulary products at home, you can switch to the
    equivalent NPH and lispro/aspart dose.

10. The typical blood glucose pattern with steroid induced diabetes is an increase in premeal blood
    glucose throughout the day (i.e. the fasting morning sugar is the lowest, prelunch is the higher,
    predinner is even higher, and bedtime is typically the highest and then it returns to its lowest level the
    next morning).

    This sort of pattern is best treated with prandial insulin given before meals. If the morning fasting
    blood glucose is > 200, the patient will need basal insulin in addition to prandial insulin.

11. Storage and stability of insulin.
     Unopened vials should be stored in the refrigerated but NOT frozen.
     Opened vials can be stored at room temp (<86F) for 1 month
     Opened vials should not be used for more than 1 month even if stored in the refrigerator.
     Disposable pens and cartridges for pens should not be stored in the refrigerator once opened.
        Expiration at room temp varies with product - see package insert.

12. Pharmacy Procedures/PharmNet Order Entry
     All SQ insulin orders MUST be written on the Sub-Q insulin order form. If you receive insulin
       orders NOT on the form they must be clarified and re-written on the order form. We do have
       physician buy in on this, but it will require on-going education. Clinical pharmacists please
       educate your teams!
     Enter each administration time separately
     Use order sets to standardize order entry
     Enter orders by Insulin type – e.g. Lispro, Glargine, etc. (new order sets)
               Dose = See Order (after nursing education completed in January)
               Quantity per dose = 1 unit
               Dispense Category = Insulin
               Initial Doses = 0
     Enter “Patient Specific Vial” for insulin types not stocked on units (e.g. for Aspart, 70/30)
               Dose = Insulin Name
               Quantity per dose = 1 vial
               Frequency = On Call prn
               Dispense Category = Bulk
               Initial Doses = 1
     SAM Insulins – separate entries for doses and vials
               SAM Vials
                         Dose = SAM VIAL
                         Quantity per dose = 1000 units
                         Frequency = On Call prn
                         Dispense Category = SAM PrePack
                         Initial Doses = 1
               SAM Administered doses
                         Dose = SAM – See Order
                         Quantity per dose = 1 unit
                         Frequency = based on order
                         Dispense Category = Bulk
                         Initial Doses = 0

UWMC Dept of Pharmacy
JKelly 2/25/2012
       Algorithms – Premeal and HS
                Enter by Insulin Type
                Low, Medium, High, Individual
                Dispense Category = Insulin
                Initial Doses = 0

UWMC Dept of Pharmacy
JKelly 2/25/2012

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