C H A P T E R 3 8
Agents to control blood glucose levels
591
■■
Sulfonylureas work only if the pancreas has
functioning beta cells.
■■
Other oral hypoglycaemic agents work to slow GI
absorption of glucose, increase release of insulin by
beta cells, increase insulin-receptor-site sensitivity
and/or block liver release of glucose.
■■
In times of severe stress, individuals regulated on
other oral hypoglycaemic agents usually need to be
switched to insulin to control blood glucose levels.
■■
Proper diet and exercise are the backbone of diabetes
mellitus management; oral hypoglycaemic drugs are
adjuncts to help control blood glucose levels.
GLUCOSE-ELEVATING AGENTS
Glucose-elevating agents, as the name implies, raise
the blood level of glucose when severe hypoglycae-
mia occurs (less than 4.4 mmol/L [40 mg/dL]). Some
adverse conditions are associated with hypoglycaemia,
including pancreatic disorders, kidney disease, certain
cancers, disorders of the anterior pituitary and unbal-
anced treatment of diabetes mellitus (which can occur if
the person takes the wrong dose of insulin or oral hypo-
glycaemic agents or if something interferes with food
intake or changes stress or exercise levels). One agent
is used to elevate glucose in these conditions: glucagon
(
GlucaGen
). Pure glucose can also be given orally or
intravenously to increase glucose levels.
KEY POINTS
Therapeutic actions and indications
These agents increase the blood glucose level by decreas-
ing insulin release and accelerating the breakdown of
glycogen in the liver to release glucose. They are indic
ated for the treatment of hypoglycaemic reactions
related to insulin or oral hypoglycaemic agents, for
the treatment of hypoglycaemia related to pancreatic
or other cancers and for short-term treatment of acute
hypoglycaemia related to anterior pituitary dysfunction
(Table 38.4).
Pharmacokinetics
Glucagon is given parenterally only and is the preferred
agent for emergency situations. Glucagon is rapidly
absorbed and widely distributed throughout the body.
It is excreted in the urine.
Contraindications and cautions
There are no adequate studies on glucagon and preg-
nancy, so use should be reserved for those situations in
which the benefits to the mother outweigh any potential
risks to the fetus. Caution should be used during breast-
feeding because the drug may cause hyperglycaemic
effects in the baby. Caution should be used in individu-
als with renal or hepatic dysfunction or cardiovascular
disease.
schedule for follow-up and disease monitoring;
and the need for follow-up lab testing
to enhance
knowledge of drug therapy and to promote
compliance.
Evaluation
■
■
Monitor the person’s response to the drug
(stabilisation of blood glucose levels).
■
■
Monitor for adverse effects (hypoglycaemia,
GI distress).
■
■
Evaluate the effectiveness of the teaching plan
(person can name drug, dosage, adverse effects to
watch for and specific measures to avoid them).
■
■
Monitor the effectiveness of comfort measures and
compliance with the regimen.
TABLE 38.4
DRUGS IN FOCUS Glucose-elevating agent
Drug name
Dosage/route
Usual indications
glucagon (GlucaGen)
Adults and children >20 kg: 0.5–1 mg SC, IM
or IV
Children <20 kg: 0.5 mg SC, IM or IV
To counteract severe hypoglycaemic
reactions
Prototype summary: Glucagon
Indications:
Counteracts severe hypoglycaemic
reactions in diabetic people treated with insulin.
Actions:
Accelerates the breakdown of glycogen
to glucose in the liver, causing an increase in blood
glucose levels.
Pharmacokinetics:
Route Onset
Peak
Duration
IV 1 min
15 mins
9–20 mins
T
1/2
:
3 to 10 minutes; metabolised in the liver and
excreted in the urine and bile.
Adverse effects:
Hypotension, hypertension, nausea,
vomiting, respiratory distress with hypersensitivity
reactions, hypokalaemia with overdose.
