8. Anti- depressants Flashcards
Name the different GROUPS of drugs used to treat depression?
- Mono amine oxadase inhibitors (MAOI)
- Tricyclic antidepressents
- Selective serotonin re-uptake inhibitors (SSRI)
- Serotonin norepinephrine up-take inhibitor (SNRI)
- Mirtazapine
- Risperidone
- Lithium
What are the 3 MAOIs for depression?
How do they work?
Phenelzine
Selegiline – also used in Parkinsons
Tranylcypromine
MoA:
Inhibit the activity of MAO enzymes.
MAO breaks down norepinephrine/serotonin and dopamine
Inhibiting MAO increases level of all three transmitters
Side effects of MAOIs?
Weakness and fatigue
Headache and dizziness
Weight gain
Impotence
Risks and interactions to consider when prescribing MAOIs?
Should not be used in combination with SSRI/ Tricyclic and some analgesics (such as morphine/ Tramadol) as they will increase serotonin to potentially dangerous levels causing confusion, hypertension, tremor, coma and possibly death. i.e. neuroleptic malignant syndrome.
Give 14 days washout after stopping MAOI before starting other antidepressants.
Food high in tyramine, causes hypertensive crisis e.g. cheese, certain meats (venison, alcohol, some green veg
Name an example of a RIMA? and how it works?
Moclobemide: Reported to act by reversible inhibition of MAO type A
- Therefore called RIMA
- Tyramine has less of an effect
- Short acting so medications can be changed with only one week washout period.
Name 5 tricylic antidespressants?
“ptyline”
“pramine”
∗ Amitriptyline ∗ Nortriptyline ∗ Clomipramine ∗ Imipramine ∗ Lofepramine
What is the MoA for tricylic antidepressants?
Act by inhibiting re-uptake of norepinephrine and serotonin by blocking the transporters responsible for re-uptake of these neurotransmitters.
Increasing concentration of neurotransmitters in the synapses and triggering further neurotransmission.
Pain control effect: By their direct effect on pain, and also through beneficial effects on sleep
tricyclic antidepressants are used to treat….
∗ Depression ∗ Anxiety ∗ Chronic pain (i.e. fibromyalgia, reflex sympathetic dystrophy syndrome) ∗ IBS ∗ Neuralgia ∗ OCD ∗ Nocturnal enuresis ∗ PTSD
Side effects of tricyclic antidespressants?
- Reduced intestinal mobility
- Bradycardia then tachy
- Reduce bronchial secretions
- Urinary retention
- Dry mouth
- Confusion
Risks and drug interactions to be cautious of when prescribing tricyclic antidepressants?
∗ Tricyclics should be used with caution in cardiovascular disease due to risk of arrythmias
With TRAZODONE: This drug is more sedating
- Concerns: tricyclics are very dangerous in overdose so beware of how much you prescribe for a patient and use with caution in patients at high risk of suicide.
List the following SSRIs in order of most to least toxic? Fluoxetine Paroxetine Citalopram (QT interval) Sertraline Escitalopram
[Most toxic] Citalopram (QT interval) Escitalopram Paroxetine Sertraline Fluoxetine [Least toxic]
How do SSRIs work?
Work by increasing levels of neurotransmitter serotonin by limiting its re-absorption and pure SSRI have only a weak affinity for norepinephrine and dopamine transmitters
Serotonin receptors are know as 5-hydroxytryptamine (5-HT)
What are 5-HT receptors and where are they found?
5-HT receptors are found in the PNS and CNS and mediate both excitatory and inhibitory neurotransmission.
These receptors modulate the release of many neurotransmitters: GABA, Dopamine, Epinephrine, Norepinephrine, Acetylcholine
They influence aggression, anxiety, cognition, learning memory, mood and sleep
What are SSRIs used for?
∗ Depression ∗ Anxiety (alone i.e. no depression) ∗ OCD ∗ Panic disorder ∗ PTSD ∗ Eating disorders (stimulates appetite as well)
List the side effects of SSRI's under the following categories: Sexual Cardiac Bleeding Suicide Overdose Epilepsy Other
SEXUAL: dysfunction and reduced libido
CARDIAC: some, especially citalopram, to be used with caution as can cause QT interval prolongation
BLEEDING: affects anticoagulants (i.e. warfarin and aspirin) and also increased risk of GI bleeds.
SUICIDE: possible increased risk of suicide especially in children and adolescents
OVERDOSE: safer than other antidepressants
EPILEPSY: may reduce fit threshold
OTHER:
- Nausea
- Rash
- Muscle aches
- Insomnia
- Sweating
