C H A P T E R 3 5
Hypothalamic and pituitary agents
525
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The hypothalamus releases hormones that act as
releasing factors, stimulating the anterior pituitary
to release specific stimulating factors and inhibiting
factors that act to stop the production of specific
anterior pituitary hormones.
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The hypothalamic hormones are not all available for
pharmacological use; those that are available are used
mostly for diagnostic testing, for treating some forms
of cancer or as adjuncts in fertility programs.
DRUGS AFFECTING ANTERIOR PITUITARY
HORMONES
Agents that affect pituitary function are used mainly
to mimic or antagonise the effects of specific pituitary
hormones. They may be used either as replacement
therapy for conditions resulting from a hypoactive pitu
itary or for diagnostic purposes. Antagonists are also
available that may be used to block the effects of the
anterior pituitary hormones (Table 35.2).
KEY POINTS
G
rowth hormone agonists
The anterior pituitary hormone that is most commonly
used pharmacologically is growth hormone. GH is
responsible for linear skeletal growth, the growth of
internal organs, protein synthesis and the stimula
tion of many other processes that are required for
normal growth.
Hypopituitarism
is often seen as GH
Safe medication administration
When receiving GH, the child’s family will need instructions
on storage, preparation and administration (see
implementation in Care considerations). They must also be
advised to report any lack of growth, as well as signs of
glucose intolerance (thirst, hunger, voiding pattern changes)
or thyroid dysfunction (fatigue, thinning hair, slow pulse, puffy
skin, intolerance to the cold).
The use of GH involves an interrelationship among many
subspecialists and expensive and regular medical evaluation
and care. The key to the success of this therapy may be the
attitude and cooperation of the young person.
TABLE 35.2
DRUGS IN FOCUS Drug affecting anterior pituitary hormones
Drug name
Dosage/route
Usual indications
Growth hormone agonists
somatropin
(Genotropin,
Omnitrope)
Dose varies with each product, check
manufacturer’s instructions; must be given
SC or IM
Treatment of children with growth failure
due to lack of growth hormone (GH)
or to chronic renal failure replacement
of GH in people with GH deficiency;
long-term treatment of growth failure in
children born small for gestational age
who do not achieve catch-up growth by
2 years of age; treatment of short stature
associated with Turner syndrome or
Prader-Willi syndrome; also approved to
increase protein production and growth in
various AIDS-related states
somatropin rDNA origin
(Humatrope, Zomacton)
0.1 mg/kg SC for 4 weeks
Reserved for use in treatment of adults
with short bowel syndrome who are
receiving specialised nutritional support
Growth hormone antagonists
bromocriptine
mesylate (Parlodel)
1.25–2.5 mg/day PO
Treatment of acromegaly in people who
are not candidates for or cannot tolerate
other therapy; not recommended for
children <15 years
lanreotide (Somatuline)
60–120 mg SC every 42–56 days
Treatment of acromegaly and carcinoid
syndrome associated with carcinoid
tumours
octreotide (Sandostatin)
100–500 mcg SC t.d.s.; adjust dose in elderly
people
Treatment of acromegaly in adults who
are not candidates for or cannot tolerate
other therapy
pegvisomant
40 mg SC as a loading dose, then 10 mg/day
SC
Treatment of acromegaly in adults who are
not candidates for or who cannot tolerate
other therapy
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