Antidepressants Flashcards
What was depression originally thought to be caused by?
- Low levels of serotonin
- Now not as clear but likely a reduction in serotonin receptors in hippocampus
WHat were the first class of antidepressants developed?
Mono Amine Oxidase Inhibitors (MAOI)
What does Mono Amine Oxidase break down?
- Norepinephrine
- Serotonin
- Dopamine
MAOIs therefore increase the levels of these 3 transmitters
What are some common MAOIs?
- Phenelzine
- Selegiline - also used in parkinsons
- Tranylcypromine
What are the side effects of Mono Amine Oxidase inhibitors MAOIs?
- Weakness
- Headache
- Weight gain
- Dizziness
- Fatigue
- Impotence
What should MAOIs not be used in combination with?
- SSRI/Tricyclic
- Analgesics such as morphine/tramadol as they will increase serotonin to potentially dangerous levels
How many days should be given after stopping MAOI before starting other antidepressants?
14
What foods should you avoid whilst taking MAOIs?
Foods high in tyramine may also cause a hypertensive crisis
- Cheese
- Certain meats such as venison
- Alcohol
- Some green vegetables i.e broad beans
How do Reversible MAOIs differ to MAOIs?
- Reversible inhibition of MAO type A ]
- Tyramine has less of an effect
- Only 1 week washout period
How do tricyclic antidepressants work?
- Inhibit re-uptake of norepinephrin and serotonin by blocking the transporters responsible for their re-uptake
- Increase concentration of neurotransmitters in the synapses and triggering further neurotransmission
What are tricyclic antidepressants used for?
- Depression
- Anxiety
- Chronic pain (i.e fibromyalgia, reflex sympathetic dystrophy syndrome)
- IBS
- Neuralgia
- OCD
- Nocturnal enuresis
- PTSD
What are the side-effects of tricyclic antidepressants?
- Arrythmias
- Antimuscarinic activity that blocks activity of the muscarinic Ach receptor and so reduce intestinal mobility
- Bradycardia followed by tachycardia, reduced bronchial secretions, urinary retention, dry mouth and confusion (not used in elderly)
- Use with caution in patients with high risk of suicide (very dangerous in overdose)
What are the common tricyclic antidepressants?
- Amitriptyline
- Clomipramine
- Imipramine
- Lofepramine
- Nortriptyline
What is a drug relating to tricyclics?
- Trazodone - more sedating
How are SSRIs believed to work?
- Limit re-absorption of serotonin thus increasing its leves
- Have only a weak affinity for norepinephrine and dopamine
- Most prescribed, Cleaner, less side-effects, better tolerated
What are serotonin receptors known as?
5-hydroxytryptamine (5-HT)