Fluoxetine – Drug Study & Nursing Considerations

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Fluoxetine Drug study

GENERAL DESCRIPTION

Fluoxetine is an antidepressant and classified in serotonin reuptake inhibitors (SSRIs). Fluoxetine was the first SSRI to reach general clinical use.

GENERIC NAME: Fluoxetine

BRAND NAME: Prozac

MECHANISM OF ACTION

Fluoxetine work by elevating serotonin neurotransmitter in the brain. At presynaptic serotonergic neuron, this interact with postsynaptic neuron which have postsynaptic receptors which are 5-HT. serotonin is synthesized from amino acid tryptophan by serotonergic neurons. These serotonin is stored in vesicles for regulated release.

At presynaptic noradrenergic neuron, this interact with postsynaptic neuron which have postsynaptic receptors which are β and α1. Norepinephrine is synthesized from amino acid tyrosine by noradrenergic neurons and stored in vesicles awaiting regulated release.

When serotonin and NE release from the neuron they stimulate their receptors and at the same time they transported back to their neurons by a process called reuptake. Serotonin is reuptake by serotonin transporter or SERT and norepinephrine is transported back to their neuron by norepinephrine transporter or NET. Once both chemicals reabsorb they partially repacked in synaptic vesicles in partially broken down into inactive metabolites by an enzyme monoamine oxidase or MAO.

As from the name of group described fluoxetine selectively inhibit reuptake of serotonin by blocking the SERT which resulted in increased levels of serotonin available to bind postsynaptic 5-HT receptors.

PHARMACOKINETICS

Fluoxetine is an orally active antidepressant. It is metabolized by hepatic CYP2D6 and 2C9. The half-life of fluoxetine is 53 hours and its active metabolite is norfluoxetine which has half-life of 240 hours i.e. 10 days. It has 70% bioavailability and 94% protein binding.

INDICATIONS

Depression

Generalized anxiety

Post-traumatic stress disorder

Obsessive compulsive disorder

Premenstrual dysphoric disorder

Bulimia nervosa

CONTRAINDICATIONS

NSAIDs

Hepatic failure

Renal failure

Epilepsy

Lithium, MAOIs, tryptophan

SIDE EFFECTS & ADVERSE EFFECTS

Manic episodes

Decrease libido

Weight gain

Insomnia

Increase in anxiety

Irritability

Sexual side effects include erectile dysfunction

Nausea

Vomiting

Diarrhea

Abrupt with drawl may cause temporary deficiency of serotonin which may lead to headache, nausea, vomiting, agitation, sleep disturbance.

Serotonin syndrome

DRUG INTERACTION

Nefazodone may cause acute hypotension and weakness when given with fluoxetine.

Cyproheptadine may cause oppose the antidepressant effect of fluoxetine

Grape juice can increase the plasma levels and may cause serotonin like syndrome when given with fluoxetine.

Clarithromycin may cause acute fluoxetine toxicity when given concurrently.

Serotonin syndrome may cause when metoclopramide, efavirenz, hydromorphone, oxycodone, pentazocine, pethidine, tramadol, morphine given with fluoxetine.

Fluoxetine may increase the plasma level of protease inhibitors like, ritonavir.

Tryptophan may cause central and peripheral toxicity when given with fluoxetine.

NURSING INTERVENTIONS

Enquire the complete health history of the patient including allergy, drug interactions, and family background of depression

Check lab test for CBC, blood glucose, BUN, creatinine, platelets, electrolytes, LFT

Check and identify if any neurological disorder like seizure etc.

Monitor blood pressure and pulse before and during treatment

Administer medicine at night or bed time to avoid drowsiness at day time

Observe mood swing during the treatment

Observe s/s for serotonin syndrome, if any

Observe cardiovascular or neurologic s/s for any disorder, if any

Avoid to administer MAOIs with tyramine containing food

Observe sleep-wake cycle of the patients.

PATIENT EDUCATION

IF taken MAOIs, forbid patient to take any fermented or aged food or containing tyramine.

Advise to take medicine at night or bed time to avoid drowsiness at day time and take morning dose early to avoid insomnia.

Advise patient not to discontinue treatment because it may take 2-4 weeks to start antidepressant effects

Inform the patients about the possible side effects of medication specially serotonin syndrome which may be life threatening.

Report immediately if feeling bradycardia, urinary retention, blurred vision, chest pain, and diaphoresis.

Advice to take care and slow change of posture due to dizziness and danger of fall or injuries.

Avoid driving if feeling drowsiness or dizziness.

Do not breast breast feed while taking medicine.

Do not take NSAIDs or pain killer with or till 2 weeks after treatment with fluoxetine.

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