C H A P T E R 3 8
Agents to control blood glucose levels
579
of insulin delivery that are available or under study for
future use.
Hyperglycaemic crisis
Therapeutic actions and indications
Insulin is a hormone that promotes the storage of the
body’s fuels, facilitates the transport of various metabo-
lites and ions across cell membranes and stimulates the
synthesis of glycogen from glucose, of fats from lipids
and of proteins from amino acids. Insulin does these
things by reacting with specific receptor sites on the
cell. Figure 38.3 shows the sites of action of replacement
insulin and other drugs used to treat diabetic conditions.
See Table 38.2 for indications.
Pharmacokinetics
Various preparations of insulin are available to provide
short- and long-term coverage. These preparations are
processed within the body like endogenous insulin.
However, the peak, onset and duration of each vary
because of the placement or addition of glycine and/or
arginine chains. Maintenance doses are given by the
subcutaneous route only, and injection sites need to
be rotated regularly to avoid damage to muscles and
to prevent subcutaneous atrophy. Regular insulin is
given intramuscularly or intravenously in emergency
situations.
Insulin is available in various preparations with a
wide range of peaks and durations of action. A person
may receive a combination of regular and isophane
insulin in the morning to cover the glucose peak from
breakfast (regular onset, 30 to 60 minutes) and the
lunch and dinner glucose peaks. The person may then
require another injection before bed. The types of
insulin used are determined by the anticipated eating
and exercise activities of any particular individual. It is
very important to make sure that one is using the correct
insulin preparation when administering the drug. Insulin
glargine (
Lantus
) and insulin detemir (
Levemir
) cannot
be mixed in solution with any other drug, including
other insulins.
Contraindications and cautions
Because insulin is used as a replacement hormone, there
are no contraindications. Care should be taken during
TABLE 38.2
DRUGS IN FOCUS Insulin
Drug name
Dosage/route
Usual indications
insulin (various types)
Varies based on response, diet, and activity
level
Treatment of type 1 diabetes mellitus;
treatment of type 2 diabetes mellitus
in people whose diabetes cannot be
controlled by diet or other agents;
treatment of severe ketoacidosis
or diabetic coma; treatment of
hyperkalaemia (in conjunction with
a glucose infusion to produce a shift
of potassium into the cells [polarising
solution]); also used for short courses
of therapy during periods of stress (e.g.
surgery, disease) in people with type 2
diabetes, for newly diagnosed people
being stabilised, for people with poor
control of glucose levels, and for people
with gestational diabetes
Safe medication administration
In 2009, lente insulin was removed from the market as
name confusion had occurred between Lantus insulin and
lente insulin. The pharmacokinetics and dose of insulins vary
greatly. Use caution to make sure you know which insulin is
intended for the individual person. Lantus and Levemir insulin
cannot be mixed in a syringe with any other insulin or any
other drug. Use particular caution when working with these
two insulins.
The DHBNZ Safe and Quality Use of Medicines has
released an alert informing healthcare professionals to take
extra care when giving insulin Humalog preparation. There
are three Humalog preparations available in Australia and
New Zealand: Humalog, Humalog Mix25 and Humalog
Mix50. Potential harm can result if a person is given Humalog
rapid release as opposed to Humalog intermediate release.
The Australian Commission on Safety and Quality in
Health Care (ACSQHC) has developed 10 National Safety
and Quality Health Service Standards. These Standards
aim to improve the quality of health service provision
across Australia and provide a national statement of the
level of care consumers should be able to expect from
health services. Awareness and knowledge of Standard 4
on Medication Safety is an important part of the nurse’s
and midwife’s clinical repertoire. For more information, see
.
