anti-depressants Flashcards
define depression
An episodic, recurrent illness with periods of spontaneous remission
mood disorder
describe the 2 types of depression
unipolar depression (mood, appetite, tiredness, negative self-concept)
- endogenous depression = unknown origin - reactive depression = associated with enviro event
bipolar/manic depression
(strong genetic basis, fluctuate between depression and mania)
define mania
heightened mood/euphoria, irritability, poor insight into consequences of sudden irrational decisions
severe = delusions and hallucinations
simple biochemical theory associated with depression
depression is a result of decreased brain monoamines (serotonin, dopamine, noradrenaline)
mechanism of inactivation of monoamine neurotransmitters
- re-uptake into the neuron
- breakdown by monoamine oxidases (MAOa and MAOb)
MAOa = breaks down NA & serotonin
MAOb = breaks down DA
COMT also degrades monoamines
mechanism of antidepressants
work either by blocking re-uptake or inhibiting MAO’s to produce an immediate increase in monoamine levels in the brain
therapeutic action of these drugs in delayed and only becomes apparent 2-6 weeks after chronic use
first generation anti-depressant drugs
- tricyclics e.g. amitriptyline, imipramine
2. MAO inhibitors e.g. phenelzine
second generation anti-depressant drugs
- moclobemide
2. fluoxetine (prozac) - SSRI
action of tricyclics e.g. amitriptyline, imipramine
block of NA & serotonin re-uptake
side-effects = antimuscarinic
benefits 75% of patients
action of MAO inhibitors e.g. phenelzine
irreversibly inhibits MAO’s and increases levels of NA, serotonin & DA
action of moclobemide
reversible MAO inhibitor which produces an acute increase in NA & serotonin
action of fluoxetine
potent SSRI
better tolerated than tricyclics
treatment for bipolar/manic depression
lithium carbonate
- 3-week onset of action
- no effect on unipolar depression
- low therapeutic index
(carbamazepine also used for rapid cyclers e.g. 4-5cycles/year)
