Antidepressants Flashcards
Cause of Depression?
Originally low levels Serotonin
Many had normal/high levels
Now levels of Serotonin receptors in Hippocampus
How long do SSRI’s take to have effect?
6-10 weeks
7-10 day period of side effects with no improvements
MAOI - What does it stand for?
Monoamine Oxadase Inhibitors
Examples of MAOI’s?
Phenelzine
Selegiline (Parkinson’s)
Tranylcypromine
Action of MAO?
Break down Norepinephrine/Serotonin & Dopamine
Side Effects of MAOI’s?
Weight gain Impotence (erections) Dizzy Headache Weakness Fatigue
First class of antidepressants?
MAOI’s
What can MAOI’s not be used with? Why?
Tricyclics
SSRI’s
Analgesics (Tramadol, Morphine)
Risk of Neuroleptic Malignant Syndrome (Confusion, tremor, HT, Coma, Death)
What shouldn’t be eaten/drank at same time as MAOI’s?
High in Tyramine
Cheese, Venison, Green Veg (Broads), Alcohol
Increased risk of Hypertensive Crisis (Stroke)
How long rest between MAOI’s & other meds?
14 day washout period
Example of Reversible MAOI?
Moclobemide
Action of Reversible MAOI? So other name?
Reversible inhibition of MAO Type A
‘RIMA’
Benefit of RIMA?
Less effect of Tyramine
Short acting so shorter washout - 7 days
Less side effects (no dietary restriction etc.)
Examples of Tricyclics
Amitriptyline Nortriptyline Lofeprimine Clomipramine Imipramine
Method of Tricyclics
Block reuptake of Serotonin & Norepinephrine
Inhibit transporters of reuptake
More in synapses so more neurotransmission
Uses of Tricyclics
Depression Anxiety Chronic pain (Fibromyalgia) Nocturnal Enuresis IBS OCD PTSD Neuralgia
Risks of Tricyclics
Overdose - careful with patients at high risk of suicide
CVD patients - incr. risk arrhythmias
Side Effects Tricyclics
Antimuscarinic activity - block muscarinic ACh receptors
Causes constipation (less intestinal mobility)
Brady>Tachycardia
Dry mouth
Reduced bronchial secretions
Urinary retention (catheterise)
Confusion - risk of falls in elderly
Most common Tricyclics
Ami & Nor
Fibromyalgia - pain control
Lower dose than depression
Name of drug related to Tricyclics
Trazodone
Trazodone side effects
More sedating than Tri’s - can cause insomnia at night
Problems with balance & confusion for elderly
Possible precaution for Tricyclics
Daily dispensation to limit patients use - risks with overdose
SSRI Action
Reduce Serotonin reuptake
Block 5-Hydroxytryptamine (5-HT) receptors
Pure SSRI = Weak Norepinephrine & Dopamine affinity
Examples of SSRI’s
Sertraline Citalopram Fluoxetine (Prozac) Paroxetine Escitalopram
What class of antidepressants are the most widely prescribed?
SSRI’s
Uses of SSRI’s
Depression Panic Disorder OCD PTSD Eating Disorders Anxiety
Benefits of SSRI’s
Better tolerated
Cleaner
Fewer side effects than others
Less overdose risk (just agitation for few days etc.)
Role & location of 5-HT receptors
PNS & CNS
Excitatory & Inhibitory neurotransmission
Influences on cognition, learning memory, sleep, mood, aggression & anxiety
What NT’s do 5-HT receptors modulate release of?
GABA Norepinephrine ACh Dopamine Epinephrine
Sexual Side Effects of SSRI’s
Loss of libido
Dysfunction
Cardiac side effects of SSRI’s
Prolonged QT interval (>450ms)
Esp. Citalopram
(Dose-dependent)
Bleeding effects of SSRI’s
Affects anticoagulants (Warfarin & Aspirin)
Incr. risk GI bleeds
(Fluoxetine - Action as anticoagulant)
Risk of SSRI’s for Teens & Younger?
Suicide risk
Stimulation of impulsive pathways
Less inhibition in younger people
How do SSRI’s influence epilepsy?
Reduced fit threshold
Other general side effects of SSRI’s
Nausea Rash Muscle Aches Insomnia Sweating
Order SSRI’s from highest to lowest overdose toxicity
Citalopram Escitalopram Paroxetine Sertraline Fluoxetine
2 Examples of SNRI’s
Duloxetine
Venlafaxine
Uses of Duloxetine?
Depression
Neuropathic Pain (Diabetic (periph nerve endings)& Fibromyalgia)
Stress Urinary Incontinence (Ladies - after birth - pelvic floor weak)
Side Effects of Duloxetine?
Nausea
Insomnia
Dizzy
Sudden withdrawal = Agitation, Insomnia, Sweaty
Uses of Venlafaxine?
Major Depressive Disorder Anxiety Panic Social Phobia Resistant Depression (3rd/4th line)
How is Venlafaxine metabolised?
In liver
Cytochrome P206
Desvenlafaxine
What is the method of Mirtazapine?
Presynaptic a2 adrenoreceptor antagonist
Noradrenergic & specific serotonergic antidepressant (NaSSA)
Uses of Mirtazapine?
PTSD
Anxiety
Different effects of Mirtazapine by dose?
15mg - Night - Drowsy
30-45 - Morning - Stimulant
Other Drugs with Antidepressant Properties
Antipsychotics - Risperidone
Lithium
Uses of Lithium?
Mood stability in bipolar/mania
Side Effects of Lithium
Kidney & Thyroid problems Hypothyroid Low Thyroxine Slow metabolism Low energy Lack of conc Weight gain
Important test when assessing depression?
Thyroid level tests
Hypothyroid can mimic depression
May just need to treat hypothyroid
What types of pain are antidepressants used for?
Neuropathic (nerve damage or dysfunction)
Some muscle pans
Why can antidepressants be used for pain? What dose?
Direct effect on pain mechs
No effects on pain via mood effects
10mg for pain v 400mg depression
How do Tricyclics help pain relief?
Block Serotonin & Norepinephrine reuptake by nerve endings
Increased levels of both in pain control pathways
What other effect do antidepressants have that help pain relief?
Beneficial effects on sleep
Common antidepressants for pain relief?
Ami- & Nortriptyline
Duloxetine
Other licensed use for Duloxetine?
Diabetic neuropathy
Drugs that cause prolonged QTc?
Citalopram
Domperidone (antiemetic)
Haloperidol (Antipsychotics)
Methadone
Antimicrobials (Erythro- & Clarythromycin)
Antiarrhythmics (Amiodarone & Fleicanide)
Amitriptyline
What is the problem caused by prolonged QT? Describe.
Torsades de Pointes
>450ms
Vent Tachy > Vent Fibrillation
Also risk of Vent Arrhythmia
People at greater risk of drug-induced LQTS
Elderly
Major psychiatric disorders
CV Disease
Women
