Antidepressants Flashcards
the biogenic amine theory of depression.
In other words, deficiency of monoamines such as nor-epi or serotonin in parts of the brain can result in depression whereas excess amounts may result in the affective disorder known as mania.
however, antidepressant therapy generally increases amine levels in the brain for days to weeks before actual therapeutic benefits are gained.
Antidepressant uses
- Moderate to severe depressive illness
- Severe anxiety and panic attacks
- Obsessive compulsive disorders
- Chronic pain
- Eating disorders
- Post-traumatic stress disorder
Antidepressant side effects
All of the antidepressants have a potential for lowering the threshold for seizure activity especially when alcohol is being consumed.
All of the antidepressants have the potential of causing an increase in suicidal thinking and suicidal behavior.
Antidepressant categories
- The major categories of antidepressants include:
- Monoamine oxidase inhibitors (MAOIs)
- Tricyclic antidepressants (TCAs)
- Tetracyclic antidepressants (TeCAs)
- Serotonin reuptake inhibitors (SSRIs)
- Serotonin and norepinephrine reuptake inhibitors (SNRIs)
- Norepinephrine and dopamine reuptake inhibitors (NDRIs)
Monoamine oxidase inhibitors examples
- Tranylcypromine/ Parmate
- Phenelzine/ Nardil
- Isocarcarboxazid/ Marplan
- Selegiline/ Eldepryl
**outdated, most side effects, lethal
Monoamine oxidase inhibitors (MAOI)
- MAOIs are used less commonly than the other antidepressants as they can have serious side effects, including weakness, dizziness, headaches, tremors and the potential for marked hypertension.
- MAOIs can potentiate the effects of sympathomimetics such as norepinephrine.
foods and tyramine
• Tyramine, an amino acid in humans, belongs to the amine family and as such is normally broken down by monoamine oxidase.
cheese (especially aged cheeses), soy products (especially when fermented), certain dried fruits such as raisins, meats and in red wine.
Since gastrointestinal MAO is essential for the adequate breakdown of tyramine, anyone using MAO inhibitors should avoid foods with high levels of tyramine–>serotonin syndrome
Monoamine oxidase inhibitors and crazy SE
- Increased absorption of intact tyramine can cause a potentially toxic elevation of catecholamine levels, resulting in severe headaches, nausea and hypertension.
- Hypertensive emergencies and fatal accelerated hypertension have been reported as a consequence of dietary intake of tyramine in patients taking MAOIs as well as the interaction of MAOIs with other drugs such as any of the narcotics.
Tricyclic antidepressants MOA and uses
• The exact mechanism of action of this class of drugs is not known. Diminishing the reuptake of monoamine neurotransmitters is clearly one of the chief effects.
Subsequent down regulation of postsynaptic receptors may be the true mechanism of action.
• Tricyclic are used to treat obsessive compulsive disorders, enuresis, panic attacks, chronic pain and migraine headaches as well as depression. Insomnia.
The medication is usually taken at bedtime because of sedating side effects.
Tricyclic antidepressants (TCAs) examples
• Amitriptyline/ Elavil • Amoxapine/ Asendin • Clomipramine/ Anafranil • Doxepin/ Doxepin • Desipramine/ Norpramine • Imipramine/ Tofranil • Nortriptyline/ Pamelor • Protriptylene/ Vivactil 
Tricyclic antidepressants SE
- The chief side effects are anti-cholinergic signs and symptoms such as dry mouth, constipation, urinary hesitancy, orthostatic hypotension and sedation.
- Dry mouth, one of the best-known effects, is one of many effects attributed to the effects of the drugs on muscarinic cholinergic receptors.
!!!potentially cardiotoxic and should be avoided in susceptible individuals with heart disease. Dysrythmias, torsade de pointes!!
In contrast to the SSRIs, the cyclic antidepressants can be fatal in doses as little as 10 times the daily dose.
• The toxicity is usually due to prolongation of the QT interval, leading to arrhythmias.
Amitriptyline/ Elavil
- Class: Tricyclic antidepressant (TCA)
- Indication: major depression, bipolar disorder, migraine and tension headaches, chronic pain,
- MOA: CNS modulation of both serotonin and norepinephrine, increasing levels of each of these neurotransmitters.
- Char: PO and IM. Usually taken at bedtime to minimize side effects of drowsiness and dizziness.
Amitriptyline/ Elavil SE
•TCA
Side effects: Dizziness and marked drowsiness. Anticholinergic effects such as dry mouth, constipation, urinary hesitancy and blurred vision. Stopping treatment abruptly cause withdrawal-like symptoms i.e. nausea, headache, dizziness, lethargy, and flu-like symptoms. This is referred to as discontinuation syndrome.
Tetracyclic antidepressants
- Tetracyclic antidepressants (TeCA’s) are a class of antidepressants that were first introduced in the 1970s.
- They are named after their chemical structure, which contains four rings of atoms, and are closely related to the tricyclic antidepressants (TCAs), which contain three rings of atoms.
Selective serotonin reuptake inhibitors (SSRIs)
- The selective serotonin reuptake inhibitors (SSRIs) are most commonly used- MAJOR DEPRESSION
- The main mechanism of action is the blockade of serotonin reuptake at the pre- synaptic terminal which results in the subsequent increased level of serotonin available for further neurotransmission.
SSRIs have been documented to be helpful in 50% to 70% of patients with major depression.
