Saturday, November 24, 2012

Antidepressants


ANTIDEPRESSANTS

·          Interact with norepinephrine and serotonin, neurotransmitters that regulate mood, arousal, attention, sensory processing and appetite.
·          Indication:
o         Treatment of major depressive illness, anxiety disorders, depressed phase of bipolar disorder, and psychotic depression
·          Contraindication:
o         Used with caution in patients with acute schizophrenia, mixed mania and depression, suicidal tendencies, severe renal, hepatic or cardiovascular disease, narrow-angle glaucoma and seizure disorders




TRICYCLIC ANTIDEPRESSANTS (TCA)

·          Prevent reuptake of serotonin and norepinephrine and cause them to build-up in the brain; the amassing of these neurotransmitters is thought to diminish depression
·          Indication:
o         Depression, depression accompanied by insomnia and anxiety, children less than 6 years of age with enuresis, chronic, intractable pain, Obsessive- compulsive disorders (OCDs)
·          Contraindication:
o         Concurrent use with alcohol or antihistamines can cause CNS depression
o         Concurrent use with MAO inhibitors can cause hypertensive crisis

Example:
imipramine (Tofranil®)
desipramine (Norpramin®)
amitriptyline (Elavil®)
nortriptyline (Pamelor®)
doxepin (Sinequan®)
trimipramine (Surmontil®)
protriptyline (Vivactil®)
maprotiline (Ludiomil®)
mirtazapine (Remeron®)
amoxapine (Asendin®)
clomipramine (Anafranil®)

Side Effects:

Anticholinergic effects:

ü        Dry mouth
ü        Dry nasal passages
ü        Blurred vision
ü        Constipation
ü        Agitation
ü        Urinary hesitancy or retention
ü        Delirium
ü        Ileus in older adults

Other side effects:

ü        Orthostatic hypotension
ü        Tachycardia
ü        Sedation
ü        Sexual dysfunction
ü        Weight gain
ü        Weight gain

Nursing Consideration:

ü        Switch to a different tricyclic antidepressant if the patient develops intolerable adverse effects.
ü        Notify the physician if the QT interval widens.
ü        Monitor a suicidal patient closely until the drug takes effect.
ü        Provide patient and caregiver information about the prescribed drug:
o         Full therapeutic effect may take for up to 30 days for some drugs and 10-14 days for amitriptyline use.
o         Caution patient not to abruptly stop TCA therapy (can cause nausea, headache, malaise).
o         Take with food or milk if gastrointestinal distress occurs.
o         Advise not to operate motor vehicle or dangerous machinery (if blurred vision and sedation occurs.
o         Teach how to manage hypotension.
o         Include high fiber food in the diet.
o         Provide reassurance that drug-induced decreased libido and inhibited ejaculation should resolve when TCA is discontinued.
o         Instruct patient to take daily dose at bedtime to avoid sedation and anticholinergic effect, unless otherwise prescribed.
o         Alcohol and other CNS antidepressants may increase sedation.
SELECTIVE SEROTONIN REUPTAKE INHIBITORS (SSRIs)

·          Prevent reuptake of serotonin thus elevating its levels in the brain thus reducing depression
·          Indication:
o         Depression, bulimia, panic attacks, OCDs, post-traumatic stress syndrome, premenstrual dysphoric disorder, social phobias, smoking cessation (fluoxetine)
·          Contraindication:
o         Concomitant use of MAOIs that can lead to increased serotonin levels which can cause Serotonin Syndrome (contraindicated within 14 days of taking MAOIs); renal or hepatic disorders

Example:
fluoxetine (Prozac®)
fluvoxamine (Luvox®)
paroxetine (Paxil®)
sertraline (Zoloft®)
citalopram (Celexa®)
escitalopram (Lexapro®)

Side Effects:

·          Anxiety
·          Diarrhea
·          Agitation
·          Sweating
·          Hand tremor
·          Insomnia
·          Headache
·          Nausea
·          Weight gain
·          Akathisia (motor restlessness)
·          Sexual dysfunction (diminished sexual drive, difficulty achieving erection or orgasm)

Nursing Consideration:

ü        Administer SSRI before bedtime or with food to minimize anticholinergic effect.
ü        Give reduced paroxetine dosage to patient with renal and hepatic impairment.
ü        Give fluoxetine dosage that exceeds that exceeds 20 mg daily in two divided doses- in the morning and at noon.
ü        Withhold fluoxetine if rash develops. Notify physician.
ü        Avoid abrupt withdrawal of SSRIs.
ü        Provide patient and caregiver teachings:
o         SSRIs may take a few weeks to take full therapeutic effect.
o         Advise patient to avoid operating motor vehicles or dangerous machinery due to sedation.
o         Teach patient to take daily dose at bedtime.
o         Instruct patient to take the drug with meals or snacks to enhance absorption and avoid dizziness.
o         Consult physician before taking any herbal remedy.

MONOAMINE OXIDASE (MAO) INHIBITORS

·          Stop the enzyme monoamine oxidase from dissolving serotonin and norepinephrine in the brain
·          Indication:
o         Depression not responding to other antidepressants
·          Contraindication:
o         Food rich in tyramine
o         Sympathomimetic drugs

Example:
phenelzine (Nardil®)
isocarboxacid (Marplan®)
tranylcypromine (Parnate®)
selegiline (Eldepryl®, Emsam®)

Side Effects:

·          Daytime sedation
·          Insomnia
·          Weight gain
·          Dry mouth
·          Orthostatic hypotension
·          Sexual dysfunction
·          *hypertensive crisis if taken with food that contains tyramine and sympathomimetic drugs

Hypertensive crisis:

·          Hypertension
·          Diaphoresis
·          Hyperpyrexia
·          Tremulousness
·          Tachycardia
·          Cardiac dysrhythmias

Nursing Consideration:

ü        Monitor blood pressure.
ü        Monitor for signs of hypertensive crisis.
ü        phentolamine (Regitine) 5 to 10 mg IV - antidote for hypertensive crisis
ü        Review these points with patient and caregiver:
o         Avoid foods rich in tyramine.

Foods Containing Tyramine
Mature or aged cheeses or dishes made with cheese, such as lasagna or pizza (all cheese is considered aged except cottage cheese, cream cheese, ricotta cheese, and processed cheese slices)
Aged meats such as pepperoni, salami, mordatella, summer sausage, beef logs, meat extracts, and similar products; make sure that meat and chicken are fresh and have been properly refrigerated
Italian broad beans (fava), bean curd (tofu), banana peel, over ripe fruit, avocado
All tap beers and microbrewery beer (drink no more than two cans or bottles of beer, including nonalcoholic beer or 4 ounces of wine per day
Sauerkraut, soy sauce or soybean condiments, or marmite (concentrated yeast)
Yogurt, sour cream, peanuts, Brewer’s yeast, MSG
Caffeine such as coffee, tea, or chocolate

o         Sit up for 1 minute before getting out of bed to avoid dizziness.
o         Avoid overexertion because MAO inhibitors may suppress angina.
o         Consult physician before taking OTCs, SSRIs tricyclic compounds, busperone (BuSpar), dextromethorphan, and opiate derivatives such as meperedine.
o         Avoid abrupt withdrawal of medication.

OTHER COMPOUNDS (Miscellaneous Antidepressants)

·          Exert different effects on dopamine, serotonin and norepinephrine
·          Indication:
o         Smoking cessation (Bupropion), depression, anxiety disorders
·          Contraindication:
o         Patients with seizure disorders, those undergoing discontinuation of alcohol or benzodiazepines, prior diagnosis of bulimia or anorexia nervosa
o         Avoid taking drug with MAOIs


Example:
bupropion (Wellbutrin®)
venlafaxine (Effexor®)
trazodone (Desyrel®)
nefazodone (Serzone®)
duloxetine (Cymbalta®)
amoxapine (Asendin®)

Side Effects:

·          Sedation
·          Headache
·          Dry mouth
·          Nausea
·          Loss of appetite
·          Agitation
·          Photosensitivity
·          Insomnia, seizures(bupropion)
·          Priapism (trazodone)

·          Liver damage and orhtostaic hypotension (nefazodone)
·          ECG changes, extrapyramidal symptoms/EPS and neuroleptic malignant syndrome/NMS (amoxapine)

Nursing Consideration:

ü        Observe and teach patient about side effects especially signs and symptoms of EPS and NMS.
ü        Monitor ECGs at onset and during treatment.
ü        Monitor liver function tests.
ü        Monitor BP and glucose treatment.
ü        Monitor patient’s weight.
ü        Be alert for increased risk of seizures.
ü        Provide patient teaching:
o         Teach patient about therapeutic effects.
o         Avoid use of alcohol and other CNS depressants.
o         Wear sunscreen because of photosensitivity.
o         Rise slowly from sitting or lying position.
o         Avoid abrupt withdrawal of drug.

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