Psychopharmacology Flashcards
(40 cards)
How long does it take after finding a therapeutic dose of an antidepressant for it to affect the symptoms?
3-6 weeks
Take two months before changing to another one if not working
Name antidepressants that cause lengthening of the QT interval?
TCAs
SSRIs
SNRIs
Name some TCAs and how they work?
Imipramine, amitriptyline, doxepin, clomipramine
Have active metabolites including desipramine and nortriptyline
Potentiate the action of the monoamines, noradrenaline and serotonin, by inhibiting their reuptake into nerve terminals
What are the side effects of TCAs?
Dry mouth Constipation Tremor Blurred vision Urinary retention Cardiovascular effects QT prolongation Arrhythmias Postural hypotension Convulsant activity Lowered seizure threshold Other effects Weight gain Sedation Mania (rarely) High risk of toxicity/overdose so don't give to suicidal patients
Name some monoamine oxidase inhibitors and how they work
Bind irreversibly to monoamine oxidase thereby preventing inactivation of amines such as norepinephrine, dopamine and serotonin leading to increased synaptic levels
Moclobemide, selegiline
What are some side effects of MAOIs?
orthostatic hypotension, weight gain, dry mouth, sedation, sexual dysfunction and sleep disturbance
Hypertensive crisis can occur if taken when a diet is high in tyramine-rich foods or sympathomimetics (Tyramine is present in cheese, pickled herrings, yeast extracts, certain red wines, and any food, such as game, that has undergone partial decomposition. Dopamine is present in broad beans)
Name some Selective Serotonin Reuptake Inhibitors and how they work
Selective serotonin reuptake inhibitors (SSRIs) selectively inhibit the reuptake of the monoamine serotonin (5-HT) within the synapse
Citalopram and its laevo-isomer, escitalopram, fluvoxamine, fluoxetine, paroxetine and sertraline
What are the side effects of SSRIs?
GI upset, sexual dysfunction, anxiety, restlessness, nervousness, insomnia, fatigue or sedation, dizziness
risk of bleeding
What is serotonin syndrome?
toxic hyper-serotonergic state, which can be caused by the ingestion of two or more drugs that increase serotonin levels, e.g. an SSRI combined with a monoamine oxidase inhibitor, a dopaminergic drug (e.g. selegiline) or a tricyclic antidepressant. Symptoms include agitation, confusion, tremor, diarrhoea, tachycardia and hypertension; hyperthermia is characteristic. This is a medical emergency and treatment may require admission to hospital
Name some Serotonin/Norepinephrine reuptake inhibitors and how they work
Blocker of both serotonin and noradrenaline (norepinephrine) reuptake. At higher doses, it also affects dopamine transmission
Venlafaxine, duloxetine
Name two novel antidepressants
Buproprion
Mertazepine
What are the side effects of mertazepine?
can be sedating in low dose and can cause weight gain. An uncommon adverse effect is agranulocytosis
How is treatment resistance in depression combatted?
Combination of antidepressants eg SSRI or SNRI with Mirtazepine
Adjunctive treatment with Lithium
Adjunctive treatment with atypical antipsychotic eg Quetipaine, Olanzapine or Aripiprazole
ECT
What are three classes of mood stablisers?
Lithium, anticonvulsants, antipsychotics
What tests must be done before the use of lithium?
Get baseline U&E and TSH. In women do a pregnancy test
As lithium causes hypothyroidism, renal damage and abnormalities in a foetus
What are the side effects of lithium?
Most common are GI distress including reduced appetite, nausea/vomiting, diarrhea
Thyroid abnormalities
Non Significant leukocytosis
Polyuria/polydipsia secondary to ADH antagonism. In a small number of patients can cause interstitial renal fibrosis.
Hair loss, acne
Reduces seizure threshold, cognitive slowing, intention tremor
What are the levels for lithium toxicity?
Mild- levels 1.5-2.0 see vomiting, diarrhea, ataxia, dizziness, slurred speech, nystagmus.
Moderate-2.0-2.5 nausea, vomiting, anorexia, blurred vision, clonic limb movements, convulsions, delirium, syncope
Severe- >2.5 generalized convulsions, oliguria and renal failure
What tests should be done before starting someone on valproic acid?
baseline liver function tests (lfts), pregnancy test and FBC
What are the side effects of valproic acid?
Thrombocytopenia and platelet dysfunction
Nausea, vomiting, weight gain
Sedation, tremor
Increased risk of neural tube defect secondary to reduction in folic acid
Hair loss
In what conditions is carbamazepine good for?
First line agent for acute mania and mania prophylaxis
Indicated for rapid cyclers and mixed patients
What are the side effects of carbamazepine?
Rash- most common SE seen
Nausea, vomiting, diarrhea
Sedation, dizziness, ataxia, confusion
AV conduction delays
Aplastic anemia and agranulocytosis (<0.002%)
Water retention due to vasopressin-like effect which can result in hyponatremia
How long should patients be left on antidepressants if they are working?
First episode-6 months
Second episode-2 years
Third episode-possible lifelong treatment
Need to keep on for less risk of relapse
What is the mesocortical pathway?
Projects from the ventral tegmentum (brain stem) to the cerebral cortex. This pathway is felt to be where the negative symptoms and cognitive disorders (lack of executive function) arise. Problem here for a psychotic patient, is too little dopamine
What is the mesolimbic pathway?
Projects from the dopaminergic cell bodies in the ventral tegmentum to the limbic system. This pathway is where the positive symptoms come from (hallucinations, delusions, and thought disorders). Problem here in a psychotic patient is there is too much dopamine.
