Antidepressants Flashcards
What is the cause of depression?
Originally it was thought to be low levels of serotonin but is more likely to be aa reduction in serotonin receptors in the hippocampus
Describe the mode of action of MonoAmine Oxadase Inhibitors
Inhibits MAO enzymes who’s function in to breakdown norepinephrine, serotonin and dopamine. Therefore inhibiting this enzyme increases levels of all three NTs
Name some MAOIs and the side effects
- Phenelzine,
- Selegiline (used in Parkinson’s),
- Tranylcypromine.
Side effects are weakness, headache, weight gain, dizziness, fatigue and impotence.
What are the interactions of MAOIs
They should not be used in combination with SSRI/Tricyclic, and analgesics such as morphine/tramadol. These will increase serotonin levels to potentially dangerous levels.
Foods high in tyramine such as cheese, alcohol, meats eg, venison and some green veg - causes hypertensive crisis.
Name a reversible MAOI (RIMA) and how it works
Moclobemide. It acts by reversibly inhibiting MAO type A enzymes.
How do tricyclic antidepressants work?
Inhibiting the re-uptake of norepinephrine and serotonin by blocking the transporters responsible for re-uptake
What are some of the uses of Tricyclic antidepressants?
Depression, Anxiety, Chronic pain, IBS, neuralgia, OCD, Nocturnal enuresis, PTSD
What are some of the side effects of tricyclic antidepressants?
- Increases risk of arrhythmias,
- Reduces intestinal mobility,
- Induce bradycardia followed by tachycardia,
- reduce bronchial secretions,
- urinary retention,
- Dry mouth and confusion
- Dangerous in overdose so be careful with suicide risk!
Name some common tricyclic antidepressants
- Amitriptyline,
- Clomipramine,
- Imipramine,
- Lofepramine,
- Nortriptyline.
What is Trazodone?
A drug related to the class of tricyclics which has a sedating effect.
How do selective serotonin re-uptake inhibitors work?
Increase the levels of serotonin by limiting re-absorption allowing for increased levels of the neurotransmitter. They have only a weak affinity for norepinephrine and dopamine so tend to have fewer side effects and are better tolerated.
What are the serotonin receptors?
5-hydroxytryptamine. (5-HT)
What are some of the uses of SSRIs?
- Depression
- Anxiety,
- OCD,
- Panic Disorder,
- PTSD,
- Eating Disorder
Name some examples of neurotransmitters that the 5-HT receptor modulates the release of and what impact this have.
GABA, Dopamine, Adrenaline, Noradrenaline and Acetylcholine. These NTs influence aggression, anxiety, cognition, learning memory, mood and sleep.
What are the side effects of SSRIs?
- Sexual dysfunction and reduced libido.
- Cardiac (citalopram can prolong the QT interval)
- Bleeding (increases risk of GI bleeding),
- Risk of suicide, especially in children and adolescents.
- Nausea,
- Rash,
- Sweating,
- Insomnia,
- Muscle aches,
- Epilepsy (may reduce seizure threshold)