McKenna's Pharmacology for Nursing, 2e

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C H A P T E R 2 1 Antidepressant agents

Cultural considerations

■■ BOX 21.4  Serotonin syndrome

BOX 21.3

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 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. 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.

(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, 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: www.nzf.org.nz/nzf_2287.html 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 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

Safe medication administration

Oral

Slow

6–8 hours

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.

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.