C H A P T E R 2 1
Antidepressant agents
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increased suicidality.
The SSRIs have been associated
with congenital abnormalities in animal studies and
should be used during pregnancy only if the benefits to
the mother clearly outweigh the potential risks to the
fetus. The SSRIs enter breast milk and can cause adverse
effects in the baby, so a different method of feeding
should be selected if an SSRI is required by the mother.
In New Zealand, none of the SSRIs have ever
been licensed for use in those aged less than 18 years
(however, it is recognised that off-label use occurs in this
age group). All NZ data sheets (information provided
for medicine prescribers) for all SSRIs currently state
that “Safety and effectiveness in children has not been
established”. All but fluoxetine and sertraline go further
to state that “use is not recommended in children”.
Adverse effects
The adverse effects associated with SSRIs, which are
related to the effects of increased 5HT levels, include
CNS effects such as headache, drowsiness, dizziness,
insomnia, anxiety, tremor, agitation and seizures. GI
effects such as nausea, vomiting, diarrhoea, dry mouth,
anorexia, constipation and changes in taste often occur,
as do GU effects, including painful menstruation,
The popularity of Prozac
A rise in the diagnosis of depression began in the 1990s,
with that decade’s fast-paced lifestyle, high-stress jobs,
explosion of information, and rapid change. Many people
who have high expectations of both themselves and
others are overworked and overstimulated to a point at
which they become clinically depressed.
There is now a selection of relatively safe and non-
toxic drugs that can be used to treat depression—the
selective serotonin reuptake inhibitors (SSRIs). For
several years, the SSRIs remained in the top-selling
category of prescription drugs. Fluoxetine (Prozac),
in particular, has been the subject of numerous talk
shows, books and movies. In many ways, Prozac was
the “in” drug of the 1990s.This societal phenomenon
put pressure on healthcare providers to prescribe a
drug even if it was not appropriate to a given person’s
situation. In some instances, people just wanted the drug
that helped their friend.They may not have been willing
to listen to their healthcare provider or to take the time
to be properly diagnosed; they just wanted an SSRI.
Prozac is not the solution to everyone’s problem, and it
is often difficult to explain this fact to a person. It also
may be hard to get the person to understand that this
drug is not a quick fix; it takes 4 to 6 weeks to achieve full
therapeutic effectiveness. Fortunately, the SSRIs have
the least adverse effects of the antidepressants, and such
fads usually pass in a few years.
It is important to remember the powerful effects of
the media on healthcare-seeking behaviour. As more
and more drugs are advertised in magazines and on
television, people are becoming aware of options and
“cures” that they might like to try. Education is a tricky
yet important part of any healthcare intervention and an
extremely important aspect of healthcare in our society.
Cultural considerations
BOX 21.3
Safe medication administration
When administering medications, confusion about similar
drug names may present a hazard, for example with Celica
(citalopram), Celebrex (celecoxib) and Xanax (alprazolam).
Use caution. Serious adverse effects have been reported,
as well as important loss of therapeutic effects, when the
wrong drug is given. If any of these drugs is ordered for a
person, make sure you know the indication for the drug, as
well as the generic name of the prescribed drug.
The use of SSRI’s has been linked to a condition called
serotonin syndrome or serotonin toxicity. Serotonin
syndrome is potentially life threatening as it can result
in excessive serotonergic activity at the central and
peripheral serotonin receptors. The excessive serotonergic
activity is caused by using excessive doses of a single
serotonergic drug, or from the use of a combination
of serotonergic drugs acting on the same receptors or
even from switching between antidepressants without
adequate “wash-out period”. Antidepressant drugs
e.g. SSRIs and clomipramine, lithium, St John’s wort,
pethidine, tramadol and linezolid are examples of drugs
likely to cause serotonin syndrome.
Source:
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BOX 21.4
Serotonin syndrome
Prototype summary: Fluoxetine
Indications:
Treatment of depression, OCDs, bulimia,
PMDD, panic disorders; off-label uses include
chronic pain, alcoholism, neuropathies, obesity.
Actions:
Inhibits CNS neuronal reuptake of
serotonin, with little effect on noradrenaline and
little affinity for cholinergic, histaminic or alpha-
adrenergic sites.
Pharmacokinetics:
Route
Onset
Peak
Oral
Slow
6–8 hours
T
1/2
:
2 to 4 weeks; metabolised in the liver, excreted
in urine and faeces.
Adverse effects:
Headache, nervousness, insomnia,
drowsiness, anxiety, tremor, dizziness, sweating,
rash, nausea, vomiting, diarrhoea, dry mouth,
anorexia, sexual dysfunction, upper respiratory
infections, weight loss, fever.
