Download unlock the mysteries of insulin therapy

Diabetes update
part 2
Unlock the mysteries of
insulin therapy
Learn about the traditional insulins and the newer analogs
so you can explain the options to your patient.
BY JAMES A. FAIN, RN, BC-ADM, PHD, FAAN
OF THE 17 MILLION people in the United States who
have diabetes, about 4 million take insulin to control
their blood glucose level and lower the risk of complications. People with Type 1 diabetes need three or
more injections of exogenous insulin daily to survive
because their pancreatic beta cells have been destroyed
and can’t produce endogenous insulin. People with
Type 2 diabetes may need insulin when oral medications and other measures don’t adequately control
their blood glucose level. In this article, I’ll review the
traditional insulins and discuss the newer types used
to manage both types of diabetes.
acting. (See Insulin Types and Characteristics to compare the differences.)
Rapid-acting insulins. Insulin lispro (Humalog)
and aspart (NovoLog) are rapid-acting insulin analogs
that take effect 5 to 10 minutes after injection and
remain effective for 3 to 5 hours. Rapid-acting insulins
mimic the normal meal insulin profile more closely
than short-acting insulins. Compared with the same
dose of a short-acting insulin, a rapid-acting insulin
achieves higher and more rapid peak serum insulin
levels and has a shorter duration of action. Tell your
patient to eat within 5 minutes of injecting rapidacting insulin to get the maximum benefit and to
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Animals to analogs
Insulin was introduced
in the 1920s. Most formulations were made
from beef or pork pancreas or a combination of
both. In the 1980s, manufacturers started using
genetic engineering to
modify insulin’s amino
acid sequence and produce analogs that mimic
the action of insulin
made in the human pancreas. Since then, the
Food and Drug
Administration (FDA)
has approved various
“human” insulins, which
are absorbed faster and
cause fewer allergic reactions.
Both animal and
human insulins are classified by their onset of
action: rapid-, short-,
intermediate-, and long-
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Insulin types and characteristics
Preparation, clarity
Rapid-acting
Insulin lispro (Humalog), clear
Insulin aspart (NovoLog), clear
Short-acting
Regular (Humulin R, Novolin R), clear
Regular (Iletin-pork), clear
Intermediate-acting
NPH (Humulin N, Novolin N), cloudy
Lente (Humulin L, Novolin L), cloudy
NPH (Iletin-pork), cloudy
Long-acting
Ultralente (Humulin U), cloudy
Insulin glargine (Lantus), clear
Premixed insulins, %
70/30 NPH/regular
(Humulin 70/30, Novolin 70/30), cloudy
50/50 NPH/regular
(Humulin 50/50), cloudy
75/25 lispro protamine/lispro
(Humalog Mix 75/25), cloudy
70/30 aspart protamine/aspart
(NovoLog Mix 70/30), cloudy
Onset
of action
Peak
action (hr)
Duration
of action (hr)
5 min
5-10 min
0.5-1.5
1-3
3-4
3-5
0.5-1 hr
0.5-2 hr
2-3
3-4
3-6
3-6
2-4 hr
3-4 hr
2-4 hr
4-10
4-12
8-14
10-16
12-18
10-16
6-10 hr
1 hr
0.5-1 hr
10-16
—
Depends on
insulin types in
the mixture
18-20
24
10-16
Nursing2004, March
41
reduce his risk of hypoglycemia.
Because of their rapid onset
Key teaching points about insulin therapy
of action, lispro and aspart are
• Make sure your patient knows the type or types of insulin he’s taking: brand
appropriate for use with an
name, manufacturer, and duration of action. Emphasize that his dosages must be
insulin pump, so the patient
individualized and balanced with food intake and activity level.
has more flexibility at meal• Teach him the proper way to draw up his prescribed insulin or to mix different
times. He can wait until the
types if he uses more than one. If he has trouble reading the syringe, teach him to
meal reaches the table to
use a magnifier or have someone else make sure the correct dose is drawn up.
count carbohydrates and
• Stress the importance of accuracy. Emphasize how injecting even slightly more or
less than the prescribed dose can dangerously affect his blood glucose level.
adjust his dose, then immedi• Teach him to always make sure he has the correct insulin before leaving the
ately administer a bolus before
pharmacy. Encourage him to take a used vial and compare the insulin name,
eating. The short duration of
strength, and directions.
action of rapid-acting insulin
• Explain how to safely store his insulin. Tell him to read and follow the manufacalso decreases his risk of hypoturer’s recommendations. Make sure he knows that all insulins maintain potency
glycemia 3 to 4 hours after
longer if refrigerated (but not frozen) before first use. Once he begins using an
meals.
insulin vial, he should store it at room temperature, but for no longer than 1
Short-acting insulins.
month.
Regular insulin and analogs
• Teach him the proper insulin injection sites and technique, how to recognize and
such as Humulin R and
respond to hypoglycemia, and when to call his primary care provider if he develNovolin R usually reach the
ops complications.
• Advise him to test his blood glucose level regularly and make sure he knows
bloodstream within 30 minhow to use the blood glucose meter properly.
utes of injection and work for
3 to 6 hours. Teach your
patient to carefully coordinate
the use of a short-acting
insulin with meals. Because
inconsistent or variable.
“Peakless” insulin
its onset of action is slower
Long-acting insulins. Effective for 18 to 24 hours,
glargine provides
than that of rapid-acting
insulin glargine (Lantus) and high-dose ultralente
a continuous
insulin, he must inject it 30
(Humulin U) are long-acting preparations. Approved
insulin level
to 60 minutes before meals
by the FDA in April 2000, “peakless” insulin glargine
to minimize the risk of postprovides a continuous insulin level similar to the slow,
similar to the
prandial hyperglycemia.
steady (basal) secretion of insulin from a normal panslow, steady
Because of its longer duracreas. Typically, the patient administers glargine at
(basal) secretion
tion, short-acting insulin also
bedtime, but any time is acceptable if he uses it at the
of insulin from a
increases the risk of hyposame time each day.
glycemia 3 to 5 hours after
Someone who takes multiple insulin injections may
normal pancreas.
meals.
achieve more independence with less risk of hypoRegular insulin was once
glycemia using insulin glargine. But because it has no
the only insulin used for intravenous (I.V.) administra- peak action, he needs to take a bolus of short-acting
tion, but now you can mix rapid-acting insulin lispro
insulin before each meal to prevent postprandial
with 0.9% sodium chloride or dextrose solution and
hyperglycemia. Warn him not to mix insulin glargine
give it I.V.
in the same syringe with other insulins: It’s very acidic
Intermediate-acting insulins. Insulins classified
and could interfere with their action.
as intermediate-acting take effect 2 to 4 hours after
Premixed insulins. Premixed insulins can benefit
injection and work 10 to 18 hours. They include
patients who have trouble drawing two formulations
NPH (Humulin N, Novolin N) and lente (Humulin
into one syringe because of vision problems or diffiL, Novolin L), a high-dose formulation. The incluculty understanding the technique. First-generation
sion of protamine and zinc in NPH insulin is repremixed preparations Humulin 70/30 and Novolin
sponsible for prolonging its duration of action. As
70/30 contain 70% NPH and 30% regular insulin.
with short-acting insulins, subcutaneous absorption
Although premixed insulins closely mimic normal
of intermediate- and long-acting insulins may be
insulin secretion at mealtime and afterward, they
42
Nursing2004, Volume 34, Number 3
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aren’t appropriate for most people with diabetes:
Regardless of the patient’s blood glucose level, a premixed short- and intermediate-acting insulin injected
before meals can promote inconsistent blood glucose
levels and increase the risk of hyperglycemia.
Within the past 5 years, the FDA approved two premixed insulin analogs. Humalog Mix 75/25 (75%
insulin lispro protamine/25% insulin lispro) and
NovoLog Mix 70/30 (70% insulin aspart protamine/
30% insulin aspart) both have a rapid onset and intermediate duration of action and should be injected
immediately before a meal. Compared with regular
insulin, they result in lower postprandial blood glucose readings and decrease the risk of hypoglycemia
after meals. Don’t administer these preparations I.V. or
by insulin infusion pump and don’t mix them with
any other insulin product.
Quality of life and prevention
Whether your patient takes insulin alone to manage
his diabetes or uses it to supplement oral drugs, he
must thoroughly understand what the various types
do and how to use them properly. With safe and
effective insulin therapy, he’ll enjoy a better quality
of life and may avoid the debilitating long-term
complications of diabetes.
SELECTED REFERENCES
Guthrie, R., et al.: “Glargine: A New Basal Insulin, A New Opportunity,”
Diabetes Spectrum. 14(3):120-122, 2001.
Kissin, A., and Katzeff, H.: “New Insulin Therapies for the Management of
Diabetes Mellitus,” Practical Diabetology. 21(1):14-20, 2002.
Krosnick, A.: “Five Decades of Diabetes Patient Care: The Time of My Life,”
Clinical Diabetes. 20(4):173-178, October 2002.
Rolla, A.: “Insulin Analog Mixes in the Management of Type 2 Diabetes
Mellitus,” Practical Diabetology. 21(4):36-43, 2002.
Wang, F., et al.: “Insulin Glargine: A Systematic Review of a Long-Acting
Insulin Analogue,” Clinical Therapeutics. 25(6):1541-1577, June 2003.
White, J., and Campbell, R.: “Pharmacologic Therapies,” in A Core Curriculum for Diabetes Educators, 5th edition, M. Franz (ed). Chicago, Ill., American Association of Diabetes Educators, 2003.
James A. Fain is associate dean for academic programs at the University of Massachusetts Graduate School of Nursing in Worcester and editor of the journal The
Diabetes Educator.
The author has disclosed that he has no significant relationship with or financial interest in
any commercial companies that pertain to this educational activity.
Online CE test offering: Access part 1, “Managing Diabetes with 'Agent Oral,’” listed separately in this issue, then take the
combined CE test on oral diabetes drugs and insulin therapy at http://www.nursingcenter.com/ce/nursing.
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Diabetes update
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