Psychiatry - Pharmacology Flashcards
Describe the monoamine theory.
- depression is caused by functional deficits of the monoamines NA, 5-HT, and DA
- evidence: reuptake inhibitors, receptor antagonists, MAOIs facilitate monoaminergic transmission and increased mood
- reserpine inhibits NA/5-HT and subsequently decreases mood
Describe the endocrine effects that may contribute to depression.
- hypothalamus-pituitary axis receives NA/5-HT input, controlling their discharge
- increased cortisol, PRL, CRF, decreased GH
- chronic stress is associated with increased CRF, which may precede depression
Describe the release of serotonin from neurones.
- tryptophan [tryptophan hydroxylase ->]
- 5-OH-tryptophan [L-AA-decarboxylase ->]
- 5-HT
- vesicle release, reuptake, processed to 5-HIAA
Describe the release of NA from neurones.
- tyrosine [tyrosine hydroxylase ->]
- DOPA [L-AA decarboxylase ->]
- DA [DA-B hydroxylase->]
- NA
- release, reuptake, MAO processing to MHPG
Name the three main categories of antidepressant, the types in each, and examples.
- MAOIs [phenelzine, isocarboxazid etc.]
- reuptake inhibitors
- SSRIs (fluoxine, paroxetine, citalopram, escitalopram, sertraline)
- TCAs (imipramine, amitryptiline, nortryptiline)
- NA-selective (buproprion, retoxene)
- other (St John’s wort, venlafaxine)
- receptor antagonists (mirtazipine, trazadone, ketamine)
Describe the acute management and maintenance therapy of mania.
- acute: antipsychotics (danzapine, risperidone, quetiapine, ariprazole)
- s/e: sedation, weight gain, metabolic syndrome, extrapyramidal
- maintenance may be lithium [0.5-1mmol/l] or anticonvulsants (valproate, carbamazepine, lamotrigene)
- lithium s/e: dry mouth, polydipsia / polyuria / nephrogenic DI, hypothyroidism, tremor, hair loss, weight gain
Describe the history and classification of antipsychotics.
- promethazine had a Cl- atom added to form chlorpromazine (e.g. thorazine)
- 1st gen: chlorpromazine, haloperidol, flupenthol, sulpiride etc.
- 2nd gen: clozapine, olanzapine, quetiapine, respiradone etc.
- 3rd gen: aririprazole
Describe the anatomic pathways involved with positive and negative schizophrenic symptoms.
- positive: overactivity of mesolimbic dopaminergic pathway and D2 receptors
- negative: reduced activity of mesocortical pathway and D1 receptors
- all other pathways seem to function normally
D2 antagonists will also block D2 receptors in other brain pathways. Name these pathways and which symptoms present with these.
- nigrostriatum: motor effects
- tubuloinfundibular: enhances PRL secretion
- mesolimbic: anhedonia
- prefrontal cortex: can worsen negative symptoms
Describe the made side effects of antipsychotics.
- 1st gen, generally extrapyramidal: acute dystonia, tardive dyskinesia, parkinsonism
- 2nd gen: weight gain, sedation
Describe the antipsychotic malignant syndrome [3].
- similar to malignant hyperthermia; muscle rigidity, rapid increase in temperature, confusion, HP, BPM, ARF, coma, death.
- onset over days [24-72h]
- stop antipsychotic, rapid cooling, renal support, dantidine, bromocriptine
Describe the pathway of antipsychotic use.
- 1st line: 2nd gen 6-8wk
- different 2nd gen, or 1st gen, for 6-8wk
- check diagnosis, consider psych input, social support, check compliance
- last option: clozapine
Describe the use of clozpine.
- last option after other antipsychotics have failed
- blood tests for agranulocytosis weekly (for 6m), fortnightly (6m), then monthly
- s/e: agranulocytosis, myocarditis, constipation, paresis, obstruction, perforation, weight gain, sedation, siallorhoea etc.
Describe the positive effects of BZDs.
rapid action, well tolerated, efficacious, reduces anxiety or aggression, induces sleep, reduces muscle tone, has anticonvulsant effects, and causes anterograde amnesia (blockade of a5 subunit, useful for minor surgical procedures)
Name the side effects of BZDs.
may cause sedation, psychomotor impairment, withdrawal, interaction with alcohol
