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P A R T 6
Drugs acting on the endocrine system
Therapeutic actions and indications
Glucocorticoids enter target cells and bind to cytoplas-
mic receptors, initiating many complex reactions that are
responsible for anti-inflammatory and immunosuppres-
sive effects. Hydrocortisone, cortisone and prednisone
also have some mineralocorticoid activity and affect
potassium, sodium and water levels in the body.
Glucocorticoids are indicated for the short-term
treatment of many inflammatory disorders, to relieve
discomfort and to give the body a chance to heal from
the effects of inflammation. They block the actions of
arachidonic acid, which leads to a decrease in the for-
mation of prostaglandins and leukotrienes. Without
these chemicals, the normal inflammatory reaction is
blocked. They also impair the ability of phagocytes to
leave the bloodstream and move to injured tissues, and
they inhibit the ability of lymphocytes to act within
the immune system, including a blocking of the pro-
duction of antibodies. They can be used to treat local
inflammation as topical agents, intranasal or inhaled
agents, intra-articular injections and ophthalmic agents.
Systemic use is indicated for the treatment of some
cancers, hypocalcaemia associated with cancer, haema-
tological disorders and some neurological infections.
When combined with mineralocorticoids, some of these
drugs can be used in replacement therapy for adrenal
insufficiency. See Table 36.3 for information on each
type of glucocorticoid agent.
Pharmacokinetics
These drugs are absorbed well from many sites. They
are metabolised by natural systems, mostly within the
liver, and are excreted in the urine. The glucocorticoids
are known to cross the placenta and to enter breast milk;
they should be used during pregnancy and breastfeeding
only if the benefits to the mother clearly outweigh the
potential risks to the fetus or neonate.
Beclomethasone is available in the form of a respira-
tory inhalant and nasal spray.
Betamethasone is a long-acting steroid available for
systemic, parenteral use in acute situations, as well as
orally and as a topical application.
BOX 36.2
Drug therapy across the lifespan
Corticosteroids
CHILDREN
Corticosteroids are used in children for the same
indications as in adults.The dose for children is
determined by the severity of the condition being treated
and the response to the drug, not on a weight or age
formula.
Children need to be monitored closely for any effects
on growth and development, and dose adjustments
should be made or drug discontinued if growth is severely
retarded.
Topical use of corticosteroids should be limited in
children; because their body surface area is comparatively
large, the amount of the drug absorbed in relation to
weight is greater than in an adult. Apply sparingly and do
not use in the presence of open lesions. Do not occlude
treated areas with dressings or nappies, which may
increase the risk of systemic absorption.
Children need to be supervised when using nasal
sprays or respiratory inhalants to ensure that proper
technique is being used.
Children receiving long-term therapy should be
protected from exposure to infection, and special
precautions should be instituted to avoid injury. If injuries
or infections do occur, the child should be seen by a
primary care provider as soon as possible.
ADULTS
Adults should be reminded of the importance of taking
these drugs in the morning to approximate diurnal rhythm.
They should also be cautioned about the importance of
tapering the drug rather than stopping abruptly.
Several over-the-counter topical preparations contain
corticosteroids, and adults should be cautioned to avoid
combining these preparations with prescription topical
corticosteroids.They also should be cautioned to apply
any of these sparingly and to avoid applying them to open
lesions or excoriated areas.
With long-term therapy, the importance of avoiding
exposure to infection—crowded areas, people with colds
or the flu, activities associated with injury—should be
stressed. If an injury or infection should occur, the person
should be encouraged to seek medical care. Monitoring
blood glucose levels should be done regularly.
PREGNANCY AND BREASTFEEDING
These drugs should not be used during pregnancy
because they cross the placenta and could cause adverse
effects on the fetus. If the benefit to the mother clearly
outweighs the potential risk to the fetus, they should be
used with caution. Breastfeeding women should find
another method of feeding the baby if corticosteroids are
needed because of the potential for serious adverse effects
on the baby.
OLDER ADULTS
Older adults are more likely to experience the adverse
effects associated with these drugs, and the dose should
be reduced and the person monitored very closely.
Older adults are more likely to have hepatic and/or renal
impairment, which could lead to accumulation of the
drug and resultant toxic effects.They are also more likely
to have medical conditions that could be imbalanced by
changes in fluid and electrolytes, metabolism changes,
and other drug effects. Such conditions include diabetes,
heart failure, osteoporosis, coronary artery disease and
immune suppression. Careful monitoring of drug dose
and response to the drug should be done on a regular
basis.
