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Indications for use:
- Major depressive disorder (MDD)
- Anxiety disorders
- Depressed phase of bipolar disorder
- Psychotic depression
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Additional indications for antidepressants:
- Chornic pain
- Migraines
- Neuropathies
- Sleep apnea
- Dermatologic d/o
- Panic disorder
- Eating disorders
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Drugs exert their effect on two major neurotransmitters:
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Serotonin...
regulates one's mood, arousal, attention, sensory processing and appetite.
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These medications combat depression by enhancing one's mood.
They act directly on the neurotransmitters in the brain to minimize the chemical imbalances and this helps to improve coping
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Levels of neurotransmitters - especially norepinephrine and serotonin are believed to be reduced in persons suffering from depression, lab tests are not available to check for this.
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Antidepressants block the enzymatic breakdown of norepinephrine and/or slow the reuptake o serotonin and/or norepinephrine.
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Classifications of antidepressants:
- Tricyclic antidepressants (TCA)
- Monoamine Oxidase Inhibitors (MAOIs)
- Selective Serotonin Reuptake Inhibitors (SSRI)
- Serotonin Norepinephrine Reuptake Inhibitors (SNRI)
- Atypical antidepressants - unique compound group
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One of the oldest forms of antidepressants discovered in the 50's.
Blocks reuptake of the monoamine neurotransmitters norepinephrine and serotonin in the synaptic space - intensifying their effects.
TCA's
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Examples of TCA's:
- Amitriptyline (Elavil)
- Amoxapine (Asendin)
- Doxepin (Sinequan)
- Imipramine (Tofranil)
- Desipramine (Norparmine)
- Nortiptyline (Pamelor)
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Indications for TCA's:
- MDD
- Panic
- OCD
- Eating d/o
- Enuresis
- Off label uses
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Well absorbed from GI tract
Half life typically 24 hours
Metabolized by liver
Peak concentration is 3-4 hours
TCA's
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Ten to fourteen days are required for this drug to reach effective serum
levels delaying it's onset of therapeutic action to 4-6 weeks.
TCA's
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Side effects of TCA's:
- Anticholinergic effects
- Orthostatic hypotension
- Weight gain
- Sleepiness
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Anticholinergic effects:
- Dry mouth
- Constipation
- Blurred vision
- Urinary retention
- Tachycardia
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Serious concern when taking TCA's:
Overdose.
7 day supply can be lethal
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This agent cannot be removed by dialysis since it is bound to tissue and plasma protein.
TCA's
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Toxicity can occur unintentionally due to it's narrow therapeutic range.
TCA's
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Symptoms from toxic blood levels can include:
- Sedation
- Ataxia
- Agitation
- Stupor
- Coma
- Resp Depression
- Convulsions
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Cardiovascular events may occur suddenly causing heart failure or sudden death - cardiotoxic effects may be delayed.
TCA's
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Contraindications for prescribing TCA's:
- Glaucoma
- Cardiovascular disease
- Urologic conditions such as retention or obstruction
- Pregnancy
- Benign prostatic hypertrophy
- Diabetes
- Hyperthyroid
- Respiratory disorders
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This drug is a very poor choice for elderly.
TCA's
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Drug interactions while taking TCA's:
- Alcohol
- Antiarrythmic drugs
- Atropine
- Antihistamines
- OTC cold and allergy drugs
- Cigarettes
- CNS depressants
- Cimetidine
- Lithium
- MAO's
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Concommitant use of MAO and TCA can result in a hypertensive crisis requires a wash out of at least how many days?
14 days.
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Patient education while taking TCA's:
- Drug's effects may not be realized for 4-6 weeks.
- If sedation occurs it should improve with time.
- Precautions with orthostatic hypotension
- Avoid OTC drugs
- Report eye pain immediately
- May experience side effects with abrupt d/c
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Inhibit monoamine oxidase which is an enzyme that essentially destroys neurotransmittters such as dopamine, norepinephrine and serotonin in the synaptic space.
Monoamine Oxidase Inhibitors (MAOI's)
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Examples of MAOI's:
- Isocarboxazid (Marplan)
- Phenelzine (Nardil)
- Tranylcypromine (Parnate)
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Indications for MAOI's:
- Atypical depression (mood reactivity, interpersonal hypersensitivity, hypersomnia, compulsions such as bulimia)
- Anxiety syndromes such as OCD, PTSD, agoophobia, and social anxietics.
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Prescribed 3rd line due to restrictions, interactions and serious side effects. This medication was developed about 50 years ago.
MAOI's
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Well absorbed from the GI tract and is metabolized by the liver and eliminated by the kidneys.
Categories include nonselective and selective.
MAOI's
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Side effects of MAOI's:
- Orthostatic hypotension
- Anticholinergic effects
- CNS hyperstimulation - agitation, acute anxiety, restlessness, insomnia, and euphoria
- Hepatic and hematologic dysfunction
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Serious concern when taking MAOI's:
- Dietary restrictions!
- Foods with tyramines are forbidden
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Because the enzyme MAO is necessary to break down tyramine and when this is restricted the increased levels of serum tyramine can result in severe hypertension, hyperpyrexia, tachycardia, diaphoresis, tremulousness, and cardiac dysrhythmias.
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Foods that contain tyramine:
(all aged foods)
- Fruits and veggies: Avacados, bananas, raisins, dried fruits, papaya products
- Meat tenderizers
- Canned figs
- Pods of beans (fava)
- Soy sauces
- Sour cream
- Yogurt
- All types of cheese except cottage cheese
- Pepperoni
- Pizza
- Beer
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Additional foods that contain tyramine:
- Meats - bologna, chicken liver, dried fish, liver, pickled herring, salami, sausage
- Alcoholic beverages - beer and ale, wines chianti and red wines
- Yeast
- Licorice
- Caffeine coffee
- Colas
- Tea in large amounts
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Life threatening side effect of MAOI's:
Hypertensive crisis!
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A hypertensive crisis can occur if the patient ingests:
- Foods with tyramine
- Sympathomimetic drugs such as amphetamines, levodopa, typtophan, OTC meds with ephedrine
- Another antidepressant TCA's or another different MAOI
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Symptoms of hypertensive crisis:
- Severe headache
- Palpitations
- Tightness in neck
- Throbbing, radiating headache
- Extremely high blood pressure
- Tachycardia
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Drug interactions while taking MAOI's:
- Anti-hypertensives can cause an additive hypotensive effect
- Meperidine or demerol can be fatal
- SSRI's combined with an MAOI can result in the "serotonin sydrome"
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Indications of SSRI's:
- Major depression - these antidepressants are now first line for this disorder.
- Anxiety
- Eating d/o
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Examples of SSRI's:
- Fluoxetine (Prozac)
- Sertraline (Zoloft)
- Peroxetine (Paxil)
- Citalopram (Celexa)
- Escitalopram (Lexapro)
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Side effects of SSRI's:
- Sexual dysfunction
- Weight gain
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Overall this class of drugs has an excellent safety profile, heart toxicity is not observed and other less serious effects such as sedation, urinary retention, constipation, increased heart rate, hypertension and anticholinergic effects occur less often.
SSRI's
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Onset of action is less than 4 weeks.
SSRI's
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Serious side effect of SSRI's:
Serotonin sydrome!
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Serotonin syndrome occurs when.....
patient is taking an additional medication that affects serotonin.
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Symptoms of serotonin syndrome can occur 2-72 hours:
- Mental confusion-agitation and anxiety
- Hallucinations
- Hyperreflexia
- Muscle rigidityMyoclonic jerks
- Fever and tremors
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Treatment for Serotonin Syndrome:
- Discontinue SSRI
- Provide supportive care
- May be deadly
- Severe cases may require mechanical ventilation and if left untreated this condition can be deadly.
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Increased suicidal with antidepressants.
- Increased energy with symptomatic relief.
- Disease process
- Precautions with prescribing: type of antidepressant, amount and follow up
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Withdrawal symptoms:
Patients on most antidepressants and especially the SSRI's and SNRI's should be withdrawn from the drug over a period of 4 weeks.
Withdrawal symptoms are:
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