C H A P T E R 3 5
Hypothalamic and pituitary agents
531
TABLE 35.3
DRUGS IN FOCUS Drugs affecting posterior pituitary hormones
Drug name
Dosage/route
Usual indications
desmopressin
(Minirin, Octostim)
Adult: 0.1–0.4 mL/day PO, IV, SC, intranasal
for diabetes insipidus; 0.3 mcg/kg IV over
15–30 minutes for von Willebrand’s disease;
20 mcg intranasal at bedtime for nocturnal
enuresis
Paediatric: 0.05–0.3 mL/day intranasal for
diabetes insipidus; 0.3 mcg/kg IV over
15–30 minutes for von Willebrand’s disease;
20 mcg intranasal at bedtime for nocturnal
enuresis
Treatment of neurogenic diabetes
insipidus, von Willebrand’s disease,
haemophilia; being studied for the
treatment of chronic autonomic failure
vasopressin (Pitressin)
Adult: 0.25 mL IM or SC. Can be increased
to 0.5 mL if required and repeated at 3–4 hr
intervals
Treatment of postoperative abdominal
distension and diabetes insipidus
CRITICAL THINKING SCENARIO
Diabetes insipidus and posterior pituitary hormones (desmopressin)
THE SITUATION
B.T. is a 56-year-old teacher with diabetes insipidus. Her
condition was eventually regulated on desmopressin
nasal spray, one or two sprays per nostril four times a day.
B.T. seemed highly interested in her disease and therapy
and learned to control her dose by symptom control. For
several years, her symptoms were well controlled. Then, at
her last clinical visit, it was noted that she had postnasal
ulcerations and nasal rhinitis. She also complained of several
gastrointestinal symptoms, including upset stomach,
abdominal cramps and diarrhoea.
CRITICAL THINKING
Think about the pathophysiology of diabetes insipidus.
What
are the effects of desmopressin on the body, and what
adverse effects might occur if the drug was being
absorbed inappropriately?
Because B.T. has used the drug for so many years, she may have
forgotten some of the teaching points about her disease and
drug administration. Outline a care plan for B.T. that includes
necessary teaching points and takes into consideration her
long experience with her disease and her drug therapy. Think
about specific warning signs that should be highlighted for
B.T. and ways to involve her in the teaching program that
might make it more pertinent to her and her needs.
DISCUSSION
An essential aspect of the ongoing care process is continual
evaluation of the effectiveness of the drug therapy. An
evaluation of this situation shows that B.T.’s postnasal
mucosa was ulcerated, possibly as a result of overexposure
to the vasoconstrictive properties of the drug. B.T.’s gastro–
intestinal tract also seemed to show evidence of increased
antidiuretic hormone effects. These factors suggest that
perhaps the drug was being administered incorrectly,
resulting in excessive exposure of the nasal mucosa to the
drug, increased absorption and increased levels of the drug
reaching the systemic circulation.
The care provider should watch B.T. administer a dose
of the drug to herself, then discuss the signs and symptoms
of problems that B.T. should watch for. In this case, B.T.
remembered most of the details of her drug teaching. But
when administering the drug, she tilted her head back,
tipped the bottle upside down and then squirted the drug
into each nostril. When questioned about her technique,
she explained that she had seen an advertisement on TV
about nasal sprays and realised that she had been doing it
wrong all these years. The difference in the types of nasal
sprays was explained and the entire care plan was reviewed
with B.T. The drug was discontinued and B.T. was placed
on subcutaneous antidiuretic hormone until the nasal
ulcerations healed.
As a person becomes more familiar with drug therapy,
the details about the drug may be forgotten. It is important
to remember that an individual’s teaching needs regular
updating and evaluation. This point is often forgotten when
dealing with people who have been taking a drug for years.
However, remembering to assess the person’s knowledge
about the drug can prevent problems such as B.T.’s
from developing. Because B.T. is a teacher, she might be
interested in developing a teaching protocol that will meet
her needs and serve as an appropriate reminder about
the disease and drug therapy. If B.T. is actively involved in
preparing such a plan, it will be more effective and might
be remembered much longer.
